Ausgeology. Queensland senior lessons

QCE Earth & Environmental Science · Unit 1 Topic 3: Development of the atmosphere and hydrosphere · Unit 2 Topic 2: Energy for atmospheric and hydrologic processes

Air and water.

The oxygen you breathe was made by microbes, and the water you drink may have come from space. Read eight short texts as a group, taking turns to lead the talk, and work out how air and water shape the planet.

How the lesson works

A · Air

Readings 1 to 5. Where the air came from, its layers, ozone and albedo, the greenhouse effect, and the winds.

B · Water

Readings 6 to 8. Where the water came from, why it is unusual, and how the oceans move heat and change Queensland’s rain.

Each reading

Predict, then read a part. Clarify and question as you go, and summarise at the end.

Show what you know

Screen 10. Eleven questions, one for each I can statement.

How reciprocal teaching works

You read in a group of four, one part at a time. Each of you leads one strategy: predicting, clarifying, questioning or summarising.

Every question is labelled with its strategy. Predict before each part, clarify and question as you read, and summarise at the end. Type the group’s answer before you open the model answer, and swap roles for each reading.

Choose your role in the group

What we are learning

How the atmosphere formed and changed, how its layers, ozone, albedo and greenhouse gases control the energy reaching the surface, how moving air spreads heat, where Earth’s water came from, why water is unusual, and how the oceans shape climate.

I can

  • 1discuss how volcanic outgassing formed the early atmosphere, how its gases compare with today’s, and why nitrogen is essential for life.
  • 2describe how photosynthesis changed the amount of oxygen in the air over geological time.
  • 3describe the four layers of the atmosphere and how temperature changes with height.
  • 4explain how the ozone layer protects living things and how albedo affects the climate.
  • 5explain how greenhouse gases absorb and reradiate thermal radiation from the surface to warm the atmosphere.
  • 6explain how convection cells and the Coriolis effect set wind direction, and how moving air masses affect ecosystems.
  • 7discuss theories of the origin of Earth’s water and the evidence for each.
  • 8describe the three phases of water in Earth’s spheres, the hydrological cycle and where Earth’s water is.
  • 9explain how water’s unusual properties sustain life and shape Earth processes.
  • 10explain how temperature and salinity drive the ocean conveyor belt, and its role in Europe’s climate and in nutrient and carbon dioxide cycles.
  • 11discuss the causes and effects of ENSO, and how changes to the water cycle affect ecosystems and people’s use of water.

QCE Earth & Environmental Science (QCAA syllabus 2025), Unit 1 Topic 3: Development of the atmosphere and hydrosphere and Unit 2 Topic 2: Energy for atmospheric and hydrologic processes. This lesson covers most of the two topics’ subject matter. The teacher notes at the end set out what each reading covers and what to teach alongside it.

My notebook

Printable activity

Reading record

Three pages: the four roles with question starters, a record for each reading with space for the group’s prediction, question and summary, and space to draw and label the energy budget and the Pacific in a neutral year and an El Niño.

Reading record (PDF) Editable (Word)

AAir

Reading 1: the oxygen story.

For half of Earth’s history there was almost no oxygen in the air. Where did it come from?

The air you are breathing is about 21% oxygen. Almost all of it was made by living things, starting with microbes in shallow seas billions of years ago.

This reading · about 40 minutes

  1. Predict from the title and the chart before you read.
  2. Read part 1. Clarify the words you are unsure of and ask questions about it.
  3. Read part 2, then summarise the whole reading.

Look at the title and the chart below. What do you predict this reading will say about how the air has changed? Predict

The air today
Show the numbers as a table

Part 1 · An atmosphere without oxygen

Earth’s first gases did not last. “Lighter gases such as hydrogen and helium dissipated into space” (Webb). A second atmosphere came from inside the planet: as magma rises, “the gases are released through a process called outgassing”, among them “water vapor, carbon dioxide (CO2), sulfur dioxide (SO2), carbon monoxide (CO)” (Webb). Volcanoes still do this. In an average year they release “between about 180 and 440 million tonnes of carbon dioxide”, but “By far the most abundant volcanic gas is water vapor” (USGS).

That early atmosphere was very different from today’s. Free oxygen “was absent on the early Earth” (Olson and others, 2018). Carbon dioxide was perhaps 10 to 50 times its level before the industrial era, while nitrogen may have been about as abundant as now, between 0.52 and 1.1 atmospheres of pressure 3.5 to 3.0 billion years ago (Olson and others, 2018).

Nitrogen stayed because it hardly reacts: “N2 gas is a very stable compound due to the strength of the triple bond between the nitrogen atoms” (Bernhard, 2010). Carbon dioxide dissolved in the oceans and was locked into rocks, and water vapour condensed into the oceans, but nitrogen built up in the air. It is now about 78% of dry air (NOAA). Life cannot do without it. Nitrogen “is a necessary component of many biomolecules, including proteins, DNA, and chlorophyll” (Bernhard, 2010), but most living things cannot use N2 directly. They depend on nitrogen fixation, “The process of converting N2 into biologically available nitrogen” (Bernhard, 2010), done mainly by microbes.

In part 1, what does outgassing mean? Clarify

Write one question about part 1 that the text answers, and one that it makes you wonder about. Start with “Why…”, “How…” or “What would happen if…”. Question

Why is nitrogen the main gas in the air today? Question

Part 2 · Microbes change the air

Cyanobacteria were “the first micro-organisms that could produce oxygen by photosynthesis” (Australian Museum). Some of them build stromatolites, mounds of microbes and trapped sediment. Living stromatolites still grow at Hamelin Pool in Shark Bay, Western Australia, which has “the most diverse and abundant examples of stromatolites” in the world; such structures “dominated marine ecosystems on Earth for more than 3,000 million years” (UNESCO). The oldest known stromatolites, in the Pilbara of Western Australia, are 3.48 billion years old (ScienceDaily, 2022), although scientists still debate whether the microbes that built them made oxygen.

At first the oxygen did not reach the air. It reacted with iron dissolved in seawater: “The dissolved iron and silicon combined with oxygen in the water to make insoluble iron oxides and silica”, which settled as banded iron formations, like those of the Hamersley Province in the Pilbara (Australian Museum). Only later could oxygen build up. “The first time oxygen was significantly present in the atmosphere was about 2.43 billion years ago”, and for about 200 million years the levels were “highly unstable” (University of Leeds, on Poulton and others, 2021). This is the Great Oxidation Event.

Even then, oxygen stayed low for a long time. After the event “oxygen plummeted to a tiny fraction of today’s level” for a period “spanning from roughly 2 to less than 1 billion years ago” (ScienceDaily, on Lyons and others, 2014). A second rise, from about 800 million years ago, may have brought oxygen up to the levels animals need, with the rise culminating “around c. 550 Ma” as the first large animals appeared (Och and Shields-Zhou, 2012). Since then oxygen has gone up and down, possibly reaching about 35% of the atmosphere around 300 million years ago (Olson and others, 2018), and it is now about 21%.

Oxygen through time
WhenWhat happenedOxygen in the air
4.0 to 2.5 billion years agoArchean: outgassed atmosphere, cyanobacteria appearEffectively none: below about one hundred-thousandth of today’s level
About 2.43 to 2.2 billion years agoGreat Oxidation EventRises for the first time, but unstable
About 2 to 0.8 billion years agoA long low periodDisputed: from less than 0.1% to about 40% of today’s level
About 0.8 to 0.55 billion years agoNeoproterozoic oxygenation; first large animalsRises towards modern levels
About 300 million years agoCarboniferous forestsPossibly about 35% of the air
Today20.95% of dry air

From Olson and others (2018), Poulton and others (2021) and Lyons and others (2014). The ranges are wide because the evidence is indirect.

Why did oxygen made by cyanobacteria not build up in the air straight away? Question

Which is the best summary of the whole reading? Summarise

Now write your own summary of the reading in two or three sentences, in your own words. Was your prediction right? Summarise

AAir

Reading 2: the layers of the air.

Why does it get colder as you climb a mountain, but warmer again higher up?

Up to about 600 km, the atmosphere is divided into four layers by how its temperature changes with height. NOAA also names a fifth, the exosphere, where the air fades into space. Each change of direction has a cause.

This reading · about 35 minutes

  1. Predict from the graph before you read.
  2. Read the text, clarify and question as you go.
  3. Summarise each layer in the table at the end.
Temperature with height
Show the numbers as a table

The line on the graph changes direction three times. Before you read, predict a reason for one of the changes. Predict

Four layers

The troposphere is the layer we live in. It is “11-12 miles (18-20 km) high at the equator” and “just under four miles (6 km) high at the poles”, and “almost all weather occurs in this region” (NOAA). The Sun mostly heats the ground, and the ground heats the air above it, so the air is warmest at the bottom: temperature falls “from an average around 62°F (17°C) to -60°F (-51°C) at the tropopause” (NOAA).

Above it, in the stratosphere, the temperature climbs again, “to a maximum of about 5°F (-15°C)” at about 50 km. The stratosphere “holds 19 percent of the atmosphere’s gases but very little water vapor”, and it holds the ozone layer: “Heat is produced in the process of the formation of ozone, and this heat is responsible for temperature increases” (NOAA). Ozone and oxygen absorb ultraviolet light from the Sun, and that energy warms the air.

In the mesosphere, from about 50 to 85 km, there is little ozone and the temperature falls again. The gases there “are now thick enough to slow down meteors hurtling into the atmosphere” (NOAA), which is why most meteors burn up at these heights.

Above about 85 km is the thermosphere, where “incoming high energy ultraviolet and x-ray radiation from the sun begins to be absorbed by the molecules”. Temperatures rise from “as low as -184°F (-120°C)” at the bottom to “as high as 3,600°F (2,000°C) near the top” (NOAA). The gas is so thin, though, that it would not feel hot.

What is the tropopause? Clarify

Why is the troposphere warmest at the bottom? Question

Why does the temperature rise through the stratosphere? Question

The thermosphere can reach 2,000 °C, yet it would not feel hot. Write a question you would ask to understand this, then try to answer it. Question

Summarise each layer in one line: where it is, what the temperature does, and why. Summarise

AAir

Reading 3: ozone and albedo.

Why can unprotected skin burn in 15 minutes in an Australian summer, and why does melting ice speed up warming?

Not all sunlight reaches the ground. The ozone layer absorbs most of the harmful ultraviolet, and bright surfaces reflect sunlight straight back to space.

This reading · about 40 minutes

  1. Predict, then read part 1 on ozone. Clarify and question.
  2. Read part 2 on albedo, using the chart. Clarify and question.
  3. Summarise both parts.

You will read about the “ozone hole”. Predict what it is, and whether it has got better or worse since it was found in 1985. Predict

Part 1 · The ozone layer

“The ozone layer is located in the stratosphere and surrounds the entire Earth” (NOAA). It acts as a filter for ultraviolet (UV) light. “UV-C radiation is entirely absorbed within the ozone layer”, and “Most UV-B radiation emitted by the Sun is absorbed by the ozone layer; the rest reaches Earth’s surface” (NOAA). That matters for living things: “increased exposure to UV-B radiation raises the risks of skin cancer and cataracts”, and too much UV-B “also can damage terrestrial plant life” (NOAA).

Australians know about UV. “Two in three Australians will be diagnosed with skin cancer in their lifetime”, and in January the UV Index is forecast “to be 11 or more across most of the country on clear sky days”, when “unprotected skin can be damaged in as little as 15 minutes” (ARPANSA and Cancer Council). UV is not heat: “clear skies or high temperatures cannot be relied on to determine when sun protection is needed” (ARPANSA and Cancer Council).

In 1985 scientists of the British Antarctic Survey reported “Large losses of total ozone in Antarctica”. They had measured ozone there since 1957, and found “during the springtime, a 40% or more decline” (Nature, 2019). The cause was human-made chemicals such as chlorofluorocarbons (CFCs). The Montreal Protocol to phase them out was adopted on 16 September 1987, and it “is widely regarded as the most successful ever environmental treaty” (WMO). At Kennaook/Cape Grim in Tasmania, air has been measured since 1976, and the records show a fall in ozone-depleting substances such as CFC-11 (Bureau of Meteorology). The 2025 ozone hole “was relatively small and short-lived”, and the ozone layer is expected to recover to 1980 values “by around 2066 over the Antarctic” (WMO).

Which best describes the ozone hole? Clarify

Why does it matter for living things that ozone absorbs UV-B? Question

Part 2 · Albedo

Albedo is the fraction of sunlight a surface reflects. Scientists estimate that “Earth’s average albedo” is about 0.30: about 30% of sunlight is reflected and about 70% is absorbed and warms the planet. “If Earth was completely covered in ice, its albedo would be about 0.84”, but “if Earth was covered by a dark green forest canopy, the albedo would be about 0.14” (NASA Earth Observatory).

Sea ice shows why albedo matters for climate. According to NSIDC, “thick sea ice covered with snow reflects as much as 90 percent of the incoming solar radiation”, but “A typical ocean albedo is approximately 0.06” (NSIDC). When ice melts, ponds form and then dark water is exposed, so “the albedo continues to decrease, leading to higher absorption of solar radiation and an increased rate of melting” (NSIDC). Melting makes more melting: a positive feedback.

How much sunlight surfaces reflect
Show the numbers as a table

From the chart, which surface absorbs the most sunlight? Question

Explain the ice feedback in part 2 as a chain of four or five steps, starting with “The Arctic warms”. Question

Summarise how the ozone layer and albedo each change the sunlight that reaches and warms the Earth’s surface. Summarise

AAir

Reading 4: the greenhouse effect.

Venus and Mars both have air that is mostly carbon dioxide. Why is one over 460 °C and the other about −60 °C?

Without its greenhouse gases the Earth would be frozen. With more of them, it warms. This reading explains how a few gases that, on average, make up less than 1% of the air can do that.

This reading · about 40 minutes

  1. Predict, then step through the energy model.
  2. Read part 1, clarify and question.
  3. Read part 2 with the graph and the planets table, then summarise.

Many people say greenhouse gases “trap heat”. Before you read, predict what the gases actually do to the heat. Predict

Where the Sun’s energy goes

Part 1 · Absorbing and radiating again

Sunlight arrives at the top of the atmosphere at an average of “approximately 340 watts per square meter”. “About 29 percent” is reflected back to space, “About 23 percent of incoming solar energy is absorbed in the atmosphere” and “48 percent passes through the atmosphere and is absorbed by the surface” (NASA). The warmed surface then gives off energy as infrared radiation, which we cannot see.

This is where greenhouse gases come in. “When greenhouse gas molecules absorb thermal infrared energy, their temperature rises”, and they “then radiate an increased amount of thermal infrared energy” in all directions, some of it back towards the ground (NASA). The surface is warmed both by the Sun and by this radiation from the air above. The result: the natural greenhouse effect makes the surface “more than 30 degrees warmer than it would be if it didn’t have an atmosphere” (NASA). The Earth averages about 15 °C (NASA Earth Fact Sheet); without greenhouse gases it would be about 33 °C colder (NASA GISS).

Water vapour is “responsible for about half of Earth’s greenhouse effect”, but it is a response to warming, not the cause: “Increased water vapor in the atmosphere amplifies the warming caused by other greenhouse gases” (NASA). Of the absorption, clouds cause about 25% and carbon dioxide about 20%; ozone, methane and other minor gases, with a little from particles in the air, make up the rest (NASA GISS).

What kind of radiation do greenhouse gases absorb? Clarify

Which is the best description of what greenhouse gases do? Question

Write a question about water vapour that part 1 answers, and answer it. Question

Part 2 · More gas, more warming

Before industry, carbon dioxide was “typically quoted as 278 ppm” (CSIRO). In 2024 the global average was 423.9 ppm (WMO), about 52% higher. In 2019 carbon dioxide “concentrations were higher than at any time in at least 2 million years”, and the increases “are unequivocally caused by human activities” (IPCC, 2021). Methane is more than two and a half times its pre-industrial level (WMO). At Kennaook/Cape Grim in Tasmania, CSIRO and the Bureau of Meteorology have measured some of the world’s cleanest air since 1976 and recorded “an ongoing increase in CO₂ over the last 50 years from human-induced activities” (CSIRO).

The planets next door show what the amount of gas does. Venus’s atmosphere is 96.5% carbon dioxide at a surface pressure of 92 bars, and its surface averages 464 °C (NASA): its “thick atmosphere traps heat in a runaway greenhouse effect” (NASA). Mars’s air is 95% carbon dioxide too, but its surface pressure is only 6.36 millibars, less than 1% of Earth’s, and its average temperature is about −59 °C (NASA). On Mars, “because the atmosphere is so thin, heat from the Sun easily escapes” (NASA), so its greenhouse effect is very weak.

Carbon dioxide at Mauna Loa, Hawai‘i
Show the numbers as a table
VenusEarthMars
Carbon dioxide in the air96.5%About 0.04%95.1%
Surface pressure92 barsAbout 1 bar0.0064 bars
Average temperature464 °C15 °CAbout −59 °C

NASA planetary fact sheets. Earth’s carbon dioxide from NOAA.

Venus and Mars both have air that is about 95% carbon dioxide. What explains the huge difference in their temperatures? Question

Summarise the greenhouse effect in three sentences: what the gases do, what difference they make, and why adding more matters. Summarise

AAir

Reading 5: moving air.

Why is the coast between Cairns and Cardwell the wettest part of Australia, why is western Queensland so dry, and why does most of Queensland’s rain fall in the warmer months?

The tropics get more sunlight than the poles. The atmosphere evens this out by moving air, in a pattern that sets where the world’s deserts, rainforests and winter rains are.

This reading · about 40 minutes

  1. Predict, then read part 1 and step through the model.
  2. Clarify and question.
  3. Read part 2 about Australia, then summarise.

Brisbane is on the east coast at about 27° south, and Perth on the west coast at about 32° south. Predict which season is wettest in each city. Predict

Part 1 · Three cells and a spinning Earth

Warm air near the equator rises, flows towards the poles high up, cools and sinks. If the Earth did not spin, one big loop might reach each pole. Instead, “there are three circulations in each” hemisphere (NOAA): the Hadley cell near the tropics, the Ferrel cell in the middle latitudes and the polar cell. Air sinking in the Hadley cell makes “high-pressure regions over the subtropical oceans and the world’s hot deserts” (Met Office), and NOAA points to “the number of deserts located along the 30°N/S latitude.” Sinking air warms and dries, so clouds rarely form.

The Earth’s spin also turns the winds. Because of the Coriolis effect, moving air is deflected “toward the right in the Northern Hemisphere and toward the left in the Southern Hemisphere” (NOAA). Air flowing back towards the equator is turned into the trade winds, which in the southern hemisphere “are east to south-easterly” (Bureau of Meteorology). In the middle latitudes the surface winds blow from the west: the westerlies.

All this moving air carries heat. “The net effect is to transfer energy from the tropics towards the poles in a gigantic conveyor belt” (Met Office). At 35° latitude the atmosphere carries 78% of the heat moved towards the poles in the Northern Hemisphere and 92% in the Southern Hemisphere; the ocean carries more only in the tropics between 0° and 17° north (Trenberth and Caron, 2001, via NCAR).

The circulation, step by step

In part 1, what is the Coriolis effect? Clarify

Why are many of the world’s deserts near 30° north and south? Question

Part 2 · Queensland’s winds and rain

In the southern hemisphere the sinking air of the Hadley cell makes “A band of high pressure systems” across the middle latitudes: the subtropical ridge (Bureau of Meteorology). It brings “stable and dry conditions”, and “Its effect is greatest over central Australia, where the ridge is dominant for most of the year” (Bureau of Meteorology). The ridge moves with the seasons. “From November to April, the subtropical ridge is generally south of Australia”, and “In autumn the subtropical ridge moves north, over the continent”. In the south, “it’s easier for cold fronts to reach southern Australia”, which is why winter is the wettest season in Perth and Adelaide. In the north, “trade winds begin to dominate weather” and “Conditions become more settled” (Bureau of Meteorology).

The east sides of continents are different. A humid subtropical climate “is found on the east coast of continents between 20° and 40° N and S latitude”, including “eastern Australia” (Ritter).

The south-east trade winds blow onto the Queensland coast off the sea, and “The moist wind enhances rainfall in tropical and sub-tropical areas of our east coast” (Bureau of Meteorology). Where the winds meet the coastal ranges, the air is pushed upwards, and rising air cools and forms clouds and rain. The ranges “enhance rainfall over the east coast hinterland during periods of easterly flow, and partially block moisture from penetrating further inland” (Bureau of Meteorology, 2005). The region with the highest average rainfall in Australia is “the east coast of Queensland between Cairns and Cardwell, where mountains are very close to the tropical coast”, and the summit of Bellenden Ker averages 8,068 mm of rain a year (Bureau of Meteorology, 2005). West of the ranges it is far drier: Longreach averages 433 mm a year and Birdsville 163 mm (Bureau of Meteorology).

Most of Queensland’s rain falls in the warmer months. From the Bureau’s averages, about two-thirds of Brisbane’s rain and 86% of Cairns’ falls from November to April (our calculation). “Moist easterly flow from the Pacific Ocean and Tasman Sea brings summer rain to most of the east coast” (Bureau of Meteorology, 2005), and easterly troughs, “most common during the summer months (December to February)”, set off showers and thunderstorms as they move towards the coast (Bureau of Meteorology). In the north the monsoon takes over, “a seasonal reversal of winds”, in which a low-pressure trough “draws in moist air from the Indian Ocean and southern Asian waters”, mostly in summer (Bureau of Meteorology). Cairns Airport averages 436 mm of rain in February and 27 mm in August, and Brisbane’s long-term averages are 160 mm in January and 46 mm in August (Bureau of Meteorology). Ecosystems follow the air. Much of the northern vegetation “grows rapidly during summer and senesces during winter”, then burns in the dry season (Harris and others, 2008).

Why is the coast between Cairns and Cardwell the wettest region in Australia? Question

Birdsville, at about 26° south, averages 163 mm of rain a year. Brisbane, at about 27° south, has a long-term average of about 1,150 mm. Why is western Queensland so much drier? Question

Write a “What would happen if…” question about the trade winds or the subtropical ridge, and answer it using the reading. Question

Summarise how heating, cooling and the Earth’s spin make the global winds, and what this means for Australia. Summarise

BWater

Reading 6: where the water came from.

Did Earth’s oceans come out of its own rocks, or were they delivered from space?

Scientists still argue about this. The evidence comes from tiny crystals in Western Australia, from craters on the Moon and from spacecraft that have sampled comets and asteroids.

This reading · about 40 minutes

  1. Predict, then read part 1. Clarify and question.
  2. Read part 2 with the chart. Clarify and question.
  3. Summarise both theories and the evidence for each.

Part 2 is called “A fingerprint in the water”. Predict how scientists could test where water came from, billions of years later. Predict

Part 1 · Water from inside the Earth

In Reading 1 you met outgassing: “Volcanic activity releases many different gases, including water vapor” (Webb). Early in Earth’s history this happened on a huge scale. Britannica calls the water and other gases released from inside the Earth “excess volatiles”, and says “major degassing occurred early in Earth’s history”. While the surface was very hot the water stayed as vapour, but “Below 100 °C (212 °F) all of the water would have condensed” (Britannica), falling as rain to fill the first oceans. Today the Earth adds very little new water this way: about 0.3 cubic kilometres a year (Britannica).

How early were there oceans? The best evidence is Australian. In the Jack Hills of Western Australia, geologists found a zircon crystal “as old as 4,404 +/- 8Myr”. Its oxygen isotopes show it formed from material that had “undergone low-temperature interaction with a liquid hydrosphere”, making it “the earliest evidence for continental crust and oceans on the Earth” (Wilde and others, 2001). Those early oceans may not have lasted. NASA reports that “asteroids large enough to boil away the ocean probably hit Earth several times” in the planet’s first few hundred million years.

According to part 1, how could outgassing make an ocean? Clarify

How can a zircon crystal be evidence for an ocean? Question

Part 2 · A fingerprint in the water

The other theory is that water was delivered by icy bodies from further out in the solar system. The Moon keeps the record of these impacts, because its craters have had “little erosion over billions of years” (NASA). Its cratered surface shows that “the terrestrial planets were battered”, though “the timing, sources, and dynamical implications of these impacts are controversial” (Bottke and Norman, 2017).

To test where water came from, scientists compare its D/H ratio: the amount of heavy hydrogen (deuterium) compared with ordinary hydrogen. A source with the same ratio as the oceans could have supplied them. In 2014 the Rosetta spacecraft measured comet 67P and found a ratio “more than three times greater than for Earth’s oceans” (ESA). Earlier, six comets from the distant Oort cloud averaged about twice Earth’s value, but comet Hartley 2 matched, which “expands the reservoir of Earth ocean-like water to include some comets” (Hartogh and others, 2011). Meteorites from asteroids “also match the composition of Earth’s water” (ESA), and Japan’s Hayabusa2 brought back grains from asteroid Ryugu in 2020; in 2022 scientists reported that they held “carbonated water containing salt and organic matter” (Nakamura, via phys.org).

A close match does not settle it. Ryugu’s ratio is close to Earth’s, yet a 2023 study of its minerals estimates that this kind of material supplied only “∼3%” of the hydrogen at Earth’s surface (Piani and others, 2023). Another study found that rocks like Earth’s own building blocks contain “sufficient hydrogen to deliver at least three times the amount of water contained in the Earth’s oceans” (Piani, via ScienceDaily, 2020). ESA’s summary: “the origin of Earth’s water is still an open question”.

Heavy hydrogen compared with Earth’s oceans
Show the numbers as a table

What does the chart suggest about comets like 67P? Question

Ryugu’s water matches Earth’s, yet it supplied only about 3% of Earth’s surface hydrogen. Write a question that helps explain this, and try to answer it. Question

Summarise the two theories for the origin of Earth’s water, with one piece of evidence for each. Summarise

BWater

Reading 7: an unusual liquid.

Almost all of Earth’s water is in the sea. Why does so little of it count as fresh, and what makes water so good at supporting life?

Water is found naturally on Earth as a solid, a liquid and a gas. It moves between all four spheres, and its unusual properties shape both living things and the land.

This reading · about 45 minutes

  1. Predict, then read part 1 with the chart. Sort the examples of water’s phases.
  2. Read part 2 and the properties table. Clarify and question.
  3. Summarise.

Predict where most of Earth’s fresh water is: rivers and lakes, underground, or frozen in ice. Predict

Part 1 · Where the water is, and how it moves

Of the world’s water, “over 96 percent is saline” (USGS). Oceans, seas and bays hold 96.5%. Fresh water is only about 2.5% of the total, and most of that is out of easy reach: 68.7% of fresh water is in ice caps, glaciers and permanent snow, and 30.1% is groundwater. Rivers hold just 0.006% of the fresh water (USGS, from Shiklomanov, 1993).

Water keeps moving through the hydrological cycle. “Most of the moisture in the atmosphere (about 90%) came from water evaporating from oceans, seas, lakes, and rivers”, and “The rest of the moisture in the atmosphere came from plant transpiration and (a very small amount) from sublimation” (USGS). About 495,000 cubic kilometres pass through the air each year, “as if the entire amount of water in the air were removed and replenished nearly 40 times a year” (NASA). “Once evaporated, a water molecule spends about 10 days in the air” (USGS), while “The oceans have a water residence time of 3,000 to 3,230 years” (Britannica). “Over the oceans, evaporation exceeds precipitation”, and the extra vapour is carried over land (Britannica), where it falls as the rain that fills rivers, soils and groundwater.

Where Earth’s fresh water is
Show the numbers as a table

Solid, liquid or gas? Sort water in each sphere

Why is evaporation from the oceans so important for rain on land? Question

What does “residence time” mean in part 1? Clarify

Part 2 · Why water is unusual

A water molecule has a slightly negative oxygen end and slightly positive hydrogen ends, so molecules attract one another. Without this, water “would be expected to have a boiling point nearly 200 °C (360 °F) lower than its observed boiling point” (Britannica): hydrogen sulfide, a heavier molecule, boils at about −60 °C (NIST). The attraction between molecules “is called a hydrogen bond” (University of Wisconsin–Madison), and it explains the properties in the table.

Most substances shrink when they freeze. Water does the opposite: “Upon freezing, the density of ice decreases by about 9 percent”, and “ice is less dense than liquid water, which causes it to float” (USGS). Water also “has a high specific heat capacity”: “it absorbs a lot of heat before it begins to get hot” (USGS), so “Cities near the oceans will tend to have less change and less extreme temperatures than inland cities” (USGS). At Brisbane Airport the average maximum runs from 21.0 °C in July to 29.2 °C in January; at Roma, inland at about the same latitude, it runs from 20.5 °C to 34.8 °C (Bureau of Meteorology). Turning water into vapour takes even more energy, 540 calories for each gram (Penn State), and that energy is released again when the vapour condenses in clouds.

Water’s properties at work
PropertyFor living thingsFor Earth processes
Ice is less dense than waterIce floats and covers lakes, so life survives underneath in winterWater expands as it freezes in cracks, prising rocks apart (frost wedging)
High heat capacity: 4,184 joules to warm 1 kg by 1 °CSteady temperatures in seas, lakes and bodiesOceans store heat and soften the climate of coasts
Large energy to evaporateSweating and transpiration cool animals and plantsHeat released in clouds powers storms and moves heat towards the poles
Dissolves many substancesCarries nutrients in sap and bloodChemical weathering; salt in the sea
High surface tensionInsects such as water striders stand on waterWater is drawn into soil pores and small spaces

USGS Water Science School; Britannica. The links to Earth processes are standard textbook examples.

Why are Brisbane’s summer days cooler than Roma’s, when the two are at about the same latitude? Question

Write a “What would happen if…” question about one of water’s properties, and answer it. Question

Summarise where Earth’s water is, how it moves, and two properties that make it important. Summarise

BWater

Reading 8: oceans and climate.

How can water sinking near Greenland and Antarctica, or warm water drifting across the Pacific, change the weather in Europe and Australia?

The oceans store and move enormous amounts of heat. Slow changes in their currents, and faster swings between the ocean and the air, decide where rain falls.

This reading · about 50 minutes

  1. Predict, then read part 1 and step through the conveyor belt.
  2. Read part 2 and step through El Niño and La Niña.
  3. Read part 3 about Australia’s water. Clarify, question and summarise.

Cold water is denser than warm water, and salty water is denser than fresh water. Predict where in the oceans water might sink to the sea floor. Predict

Part 1 · The global conveyor belt

Winds drive the surface currents, but deep currents are driven by differences in density. Cold, salty water is dense and sinks. This thermohaline circulation (“thermo” for heat, “haline” for salt) “drives a global-scale system of currents called the ‘global conveyor belt.’” It “begins on the surface of the ocean near the pole in the North Atlantic”, where water cools, gets saltier and sinks. Deep water flows south, and “travels around the edge of Antarctica, where the water cools and sinks again”. Eventually the deep waters warm and become less dense, “so that they rise to the surface (upwelling)”. A cubic metre of water “takes about 1,000 years to complete the journey” (NOAA).

Australia is next to one of the sinking regions. Off the Adélie Land coast directly south of Tasmania, CSIRO’s Steve Rintoul found that “about a quarter of the total volume of bottom water in the world ocean is formed there” (CSIRO, 1998). When sea ice forms it leaves salt behind, making very cold, very salty water that sinks to the sea floor.

The conveyor matters for climate and life. Its Atlantic branch, the AMOC, carries “warm water near the surface” towards the pole, “such as the Gulf Stream in the North Atlantic” (NOAA), and the Gulf Stream helps keep British winters “milder than those experienced at similar latitudes elsewhere in the world” (Met Office). Some scientists argue that the air does more of this work: “it is the atmosphere, not the ocean, that does the lion’s share” (Seager, Columbia University). The conveyor also carries nutrients and carbon dioxide: “Warm surface waters are depleted of nutrients and carbon dioxide”, and upwelling deep water brings them back (NOAA). The ocean takes up “about 30% of the carbon dioxide” released into the atmosphere (NOAA).

Climate models keep being tested against new measurements. One study found the AMOC has weakened by “around 15 per cent” since the mid-twentieth century (Caesar and others, 2018). The IPCC says it “is very likely to weaken over the 21st century”, but with “medium confidence that there will not be an abrupt collapse before 2100” (IPCC, 2021). South of Australia, the deep overturning slowed “by almost a third (30%)” between 1992 and 2017, earlier than predicted (UNSW and CSIRO, 2023).

The conveyor belt, step by step

What makes water sink in the North Atlantic and near Antarctica? Clarify

Why is upwelling important for life in the ocean? Question

Part 2 · El Niño and La Niña

In the tropical Pacific, “during the neutral phase, steady trade winds blow across the tropical Pacific from the east to west”. “These winds pile up warm water in the western Pacific”, and “the western tropical Pacific is 8–10° C warmer than the eastern tropical Pacific” (Bureau of Meteorology). Moist air rises over the warm water north of Australia, bringing clouds and rain, and sinks again in the east: “a huge connected cycle called the Walker Circulation”. The ocean and air change together, “because ENSO is a coupled climate phenomenon” (NOAA). ENSO stands for El Niño–Southern Oscillation.

In an El Niño, “Trade winds weaken or reverse, and warmer surface water builds up in the central and/or eastern Pacific”. The clouds shift east, bringing, usually, “below average winter–spring rainfall for eastern parts of the country” and “a greater risk of drought for northern and eastern Australia, higher temperatures and more heatwaves”. In a La Niña, “Trade winds strengthen and warm waters build up north of Australia”, bringing “a higher risk of widespread flooding” (Bureau of Meteorology). The Southern Oscillation Index measures the pressure difference between Tahiti and Darwin: sustained values below −7 “often indicate El Niño episodes” (Bureau of Meteorology). Each event differs: “widespread drought does not occur with every event” (Bureau of Meteorology). The Indian Ocean Dipole matters too: a positive phase brings “less rain and higher than normal temperatures over parts of Australia during winter and spring” (Bureau of Meteorology).

Queensland feels both phases. In eastern Australia “the average December–March rainfall during La Niña years is around 20% higher” than the long-term average, “particularly notable for the east coast”, and “The only years with multiple severe tropical cyclone landfalls in Queensland have been La Niña years” (Bureau of Meteorology). During El Niño, “eastern Australia has more chance of drier and warmer weather”, but “An El Niño event does not always coincide with drought in Australia” (Bureau of Meteorology, 2023).

The Pacific in three states

During an El Niño, why does eastern Australia often get less rain? Question

Part 3 · South-east Queensland’s water

Changes in the water cycle reach people and ecosystems. The Millennium Drought (2001 to 2009) was “South East Queensland’s worst drought in 100 years”, and the region’s combined dam levels “dropped to approximately 20%” (Seqwater, 2017). Wivenhoe Dam, Brisbane’s main water source, “was just 15% full in August 2007”. People “installed water efficiency devices and appliances” and reused greywater, “more than halving their water use, to just 120 litres per person per day” (Seqwater).

Then the 2010–11 La Niña, “one of the strongest observed”, brought “widespread flooding in many regions between September 2010 and February 2011” (Bureau of Meteorology). The Brisbane River peaked at 4.46 m at 3 am on 13 January 2011, “the largest flood peak recorded since the January 1974 flood” (Bureau of Meteorology). Wivenhoe Dam was built for both water supply and flood mitigation (Queensland Government, 2014), and in a flood it can “temporarily hold a further 1.967 million megalitres” on top of its drinking water (Seqwater, 2021). Modelling by Brisbane City Council indicates that without the dam the 2011 peak in the city “would have been approximately 2.0 m higher” (van den Honert and McAneney, 2011).

The drought also changed where the water comes from. “The SEQ Water Grid, Gold Coast Desalination Plant and the Western Corridor Recycled Scheme” were “built during the drought to help increase water security” (Seqwater). The desalination plant “can produce up to 133 million litres of drinking water a day” and “is less dependent on rainfall to operate” (Seqwater). Even so, “the majority of water provided to South East Queenslanders is dependent on rain” (Seqwater). At the end of July 2026 the region’s storages were at 83.5% (Seqwater, 2026).

In June 2026 the Bureau of Meteorology declared an El Niño, and on 27 October it reported that “El Niño continues to strengthen” (Bureau of Meteorology).

Why did south-east Queensland build a desalination plant during the Millennium Drought? Question

Write a question that links the conveyor belt or ENSO to people’s use of water in Queensland, and answer it from the reading. Question

Summarise how the oceans move heat, and one way changes in ocean and air together affect Australia. Summarise

5Show what you know

Show what you know.

Eleven questions, one for each of the I can statements on screen 1. You get one try at each, so think before you tap.

Which statement best describes the early atmosphere formed by volcanic outgassing?

Where did almost all the oxygen in today’s air come from?

In which layer does temperature rise with height because ozone absorbs ultraviolet light?

Arctic sea ice is shrinking. What happens to the albedo of the region, and why does it matter?

Which best explains how greenhouse gases warm the Earth’s surface?

Why do the trade winds over northern Australia blow from the south-east rather than straight from the south?

Rosetta found comet 67P’s water has more than three times as much heavy hydrogen as Earth’s oceans. What does this suggest?

About what share of Earth’s fresh water is frozen in ice caps, glaciers and permanent snow?

Why is it important for life in lakes that ice is less dense than liquid water?

What drives the deep part of the global ocean conveyor belt?

During a strong La Niña, what usually happens in the Pacific and in eastern Australia?

Printable activity

Reading record

Three pages: the four roles with question starters, a record for each reading with space for the group’s prediction, question and summary, and space to draw and label the energy budget and the Pacific in a neutral year and an El Niño.

Reading record (PDF) Editable (Word)
For teachers

Curriculum

Queensland Curriculum and Assessment Authority (QCAA), Earth & Environmental Science 2025 v1.0 General senior syllabus (January 2024), Unit 1 Topic 3: Development of the atmosphere and hydrosphere (6 hours) and Unit 2 Topic 2: Energy for atmospheric and hydrologic processes (20 hours). The syllabus is © State of Queensland (QCAA) 2024, licensed under CC BY 4.0 (www.qcaa.qld.edu.au/copyright). The two topics’ Science understanding subject matter:

Unit 1 Topic 3: Development of the atmosphere and hydrosphere

Hydrosphere

  • Explain how water’s unique properties (including its boiling point, density in solid and liquid phase, surface tension, ability to act as a solvent, and its abundance on the surface of Earth) make it an important component of Earth system processes (including precipitation, ice sheet formation, evapotranspiration and solution of salts).
  • Discuss evidence for theories on the origins of water on Earth, including volcanic outgassing and the impact of icy bodies from space.

Atmosphere

  • Explain the layered structure of the modern atmosphere as characterised by changes in temperature and movement of air masses in the troposphere, stratosphere, mesosphere and thermosphere.
  • Explain the location and role of the ozone layer in the atmosphere.
  • Discuss the evidence for theories of how the atmosphere was formed, including
    • volcanic outgassing during cooling and differentiation of Earth
    • significant modification of its composition by the actions of photosynthesising organisms.

Unit 2 Topic 2: Energy for atmospheric and hydrologic processes

Solar energy

  • Describe solar energy as electromagnetic radiation, including ultraviolet radiation.
  • Analyse how the transfer of solar energy to Earth’s surface is influenced by
    • atmospheric absorption, including ozone
    • reflection by aerosols and back-scattering
    • physical characteristics of Earth’s surface, including albedo.

Thermal radiation and the greenhouse effect

  • State that absorbed solar radiation is emitted as infrared radiation.
  • Explain how emitted infrared radiation is mostly absorbed by greenhouse gases, which re-radiate in all directions, including back towards Earth's surface.
  • Explain how this process leads to the greenhouse effect.
  • Compare the major greenhouse gases and their sources, including carbon dioxide, methane and water vapour.
  • Interpret data relevant to the greenhouse effect.
  • Interpret data about the effect of greenhouse conditions on temperature.

Atmospheric circulation

  • Explain how heating and cooling cause differences in atmospheric pressure.
  • Explain how the movement of air masses due to heating and cooling, and Earth’s rotation and revolution, cause systematic atmospheric circulation, including
    • geostrophic wind
    • the Walker Circulation.
  • Apply knowledge of air pressure to explain
    • patterns of systematic atmospheric circulation
    • the transfer of thermal energy around Earth’s surface via systematic atmospheric circulation.
  • Interpret the features of synoptic charts and satellite images, including high and low pressure and isobars.

Ocean currents

  • Identify the following key features of the ocean conveyor (also known as the thermohaline circulation)
    • sinking of dense water in the North Atlantic and regions around Antarctica
    • spreading of dense water in the deep ocean
    • broad upwelling of deep water
    • near surface currents, such as the Gulf Stream.
  • Explain how global oceans act as heat sinks.
  • Explain how the density of seawater depends on temperature and salinity.
  • Interpret evidence demonstrating systematic ocean currents are due to
    • differences in density
    • the rotation of Earth
    • the action of the wind.

Weather and climate

  • Describe weather as an interaction between the atmosphere and hydrosphere.
  • Describe the effect of the following Australian climate influences on rainfall conditions
    • El Niño and La Niña
    • Madden-Julian Oscillation
    • Indian Ocean Dipole
    • Southern Annular Mode.
  • Compare the conditions that cause El Niño and La Niña, including the Southern Oscillation Index (SOI), and their associated effects at local and global levels.
  • Interpret data to make reasoned decisions about El Niño and La Niña patterns.

Where the lesson covers them:

  • Water’s unique properties and their part in Earth system processes: Reading 7, part 2 and the properties table; x9.
  • Evidence for the origins of Earth’s water: Reading 6 and the D/H chart; x7.
  • The layered structure of the atmosphere: Reading 2 and the temperature graph; x3.
  • The location and role of the ozone layer: Reading 3; x4.
  • How the atmosphere formed, by outgassing and photosynthesis: Reading 1, the chart of today’s air and the oxygen table; x1 and x2.
  • Solar energy, ultraviolet radiation, absorption by ozone, and albedo: Reading 3 and the albedo chart; x4.
  • Infrared radiation, the greenhouse effect and the major greenhouse gases: Reading 4, the energy model, the Mauna Loa graph, and Venus and Mars; x5.
  • Heating, cooling, Earth’s rotation and systematic atmospheric circulation, including the Walker Circulation: Reading 5 (the subtropical ridge, the trade winds and Queensland’s rain) and the circulation model, and Reading 8, part 2; x6.
  • The ocean conveyor, the oceans as heat sinks, the density of seawater, and the wind and density as drivers of currents: Reading 8, part 1 and the conveyor model, and Reading 7, part 2 (heat capacity); x10.
  • Weather as an interaction between the atmosphere and hydrosphere: Reading 5 (moist winds and rain on the coast) and Reading 7 (evaporation, and the heat released when vapour condenses in clouds).
  • El Niño and La Niña, the Southern Oscillation Index and the Indian Ocean Dipole, and their effects in Queensland: Reading 8, parts 2 and 3 (rain, cyclones, the Millennium Drought and the 2011 Brisbane flood) and the Pacific model; x11.

The lesson does not cover reflection by aerosols and back-scattering, the part Earth’s revolution plays in circulation, geostrophic wind, synoptic charts and satellite images, interpreting evidence for what drives ocean currents, interpreting data on El Niño and La Niña, the Madden-Julian Oscillation or the Southern Annular Mode, so teach these alongside it. The Bureau of Meteorology’s Special Climate Statement 76, on the floods of February and March 2022 in south-east Queensland and New South Wales, names La Niña, the Southern Annular Mode and the Madden-Julian Oscillation among the influences, and suits that subject matter.

Of the Science as a human endeavour points, the lesson covers the use and banning of CFCs (Reading 3), the range of evidence behind models of the atmosphere (Reading 1) and of the ocean conveyor (Reading 8, part 1), explanations and predictions about the causes and effects of climate change (the IPCC findings in Reading 4 and Reading 8, part 1), and predictions about El Niño and La Niña (Reading 8, part 2). It does not deal directly with the point on explanations and predictions about the hydrosphere and atmosphere, and does not cover Global Atmosphere Watch, the ‘Goldilocks zone’, solar energy for sustainability and building design, or weather forecasting and the conventions of meteorology. Of the Science inquiry points, Reading 4 compares Earth’s atmosphere with Venus and Mars from secondary data, and Reading 3 describes the Antarctic ozone record that revealed the ozone hole. The other four, investigating water’s properties, collecting weather data, modelling greenhouse conditions, and interpreting ocean, pressure, rainfall and SOI data for El Niño and La Niña, need practical work or data sets.

Schools report Unit 1 and Unit 2 results to the QCAA as satisfactory or unsatisfactory, and Year 11 assessment is set by the school. The summative internal assessments come in Units 3 and 4: a data test, a student experiment and a research investigation. The Mauna Loa data, the albedo chart, the fresh-water chart and the rainfall figures in Reading 5 give practice in interpreting data, and a practical on water’s heat capacity (heating equal masses of water and sand) or on density currents (coloured salty and fresh water) gives practice for a student experiment.

How the lesson is taught

The lesson uses reciprocal teaching, developed by Annemarie Palincsar and Ann Brown. In their 1984 study, “The four study activities were summarizing (self-review), questioning, clarifying, and predicting”, and “the tutor and students took turns leading a dialogue centered on pertinent features of the text” (Palincsar and Brown, 1984). The adult models each strategy at first and then “gradually cedes her greater responsibility” to the students. The original students were “seventh grade poor comprehenders”, and the classroom transfer tests used science and social studies passages. Each reading here is split into parts, and every question is labelled with its strategy: predict before a part, clarify and question during it, summarise after it. A group of four takes the roles of predictor, clarifier, questioner and summariser, and swaps roles for each reading.

The evidence is positive, but the size of the effect depends on how it is measured and who runs it. Rosenshine and Meister’s review of sixteen studies found a median effect size of .32 on standardised tests and .88 on tests the researchers wrote (Rosenshine and Meister, 1994). A meta-analysis of whole-class reading-strategy programmes found “a very small effect on reading comprehension (Cohen’s d = .186)” on standardised tests, with larger effects when researchers rather than teachers delivered them (Okkinga and others, 2018). The Education Endowment Foundation rates reading comprehension strategies as “high impact on average (+7 months)” and notes they “can be integrated into literacy, humanities and science lessons”, but its primary trial of Reciprocal Reading found gains for the targeted version and no evidence of impact for the whole-class version (EEF). The only randomised trial in secondary schools we found, in England, found no significant effect on passage comprehension (+0.13) (Thurston and others, 2020). The What Works Clearinghouse rated reciprocal teaching as having “mixed effects for adolescent learners”. We found no controlled trial with senior secondary Earth science texts.

Teachers report that the hard parts are students’ questions and handing over too early. One teacher-researcher wrote “I too early transferred the responsibility to the pupils who weren’t able to take over that responsibility yet” (Jansen). Tes warns that reciprocal reading can turn into “whole-class, teacher-led didactic lessons where students are marched through the steps of a process” (Dixon, 2020).

  • Timing. About five and a half hours of reading (eight readings of 35 to 50 minutes), plus screens 1 and 10. Use the start of the first lesson for screen 1 and the end of the last for screen 10. Readings 1, 2, 3, 6 and 7 cover most of Unit 1 Topic 3, and Readings 3, 4, 5 and 8 most of Unit 2 Topic 2, so the readings can be split between the two units.
  • Model it first. Before groups work alone, lead the first part of Reading 1 yourself, thinking aloud through each strategy. Then let groups lead part 2 while you listen. Return to modelling whenever a group’s questions stay literal.
  • Running it. Groups of four on one device. Each role leads the talk at its point in the reading, and the whole group answers. Stop the class after part 1 of Readings 1, 4 and 8 and ask a few questioners to share their questions.
  • The model answers. A model answer opens only after the group has typed something. The prediction answers say what the reading shows; a wrong prediction is still a good one if it was reasoned.
  • Saved work. Answers save in the browser on the device being used. A group that changes devices should keep the printable record.

Handle with care

  • Climate change, drought and flood can be personal for students from farming families or from areas hit by drought, fire or flood, including the 2011 and 2022 floods in south-east Queensland. The readings report what the Bureau of Meteorology, CSIRO and the IPCC say, and the questions ask students to explain mechanisms, not to take a position.
  • The El Niño of 2026 is current. Reading 8 quotes the Bureau of Meteorology’s update of 27 October 2026. Check the Bureau’s ENSO page before teaching and update the example.
  • The lesson uses the dual name Kennaook/Cape Grim, as the Bureau of Meteorology and CSIRO do. The rivers, ranges and coasts named in Readings 5 and 8 matter to their Traditional Owners; the lesson does not tell Aboriginal or Torres Strait Islander knowledge of them, because we did not have a source approved by the Traditional Owners.

Misconceptions the readings target

  • The greenhouse effect is caused by the ozone hole (Reading 4, questions 2 and 3; x5). Dawson and Carson (2013) found among 438 Western Australian Year 10 students that “The most common misunderstanding we found was confusing the ozone layer with the greenhouse effect.”
  • Greenhouse gases reflect heat like a mirror, or form a layer (Reading 4, prediction and question 3; x5). Harris and Gold (2018) list “greenhouse gasses form a layer that reflects solar energy” among students’ models, and found that teaching how molecules absorb and re-emit radiation helps.
  • Carbon dioxide is the only greenhouse gas (Reading 4, part 1). Dawson and Carson found “up to 15% of students thought carbon dioxide was the only greenhouse gas”.
  • The early air was like today’s, or plants made the first oxygen (Reading 1; x1 and x2).
  • It gets steadily colder all the way up (Reading 2; x3).
  • The ozone hole is a hole with no ozone (Reading 3, prediction and question 2).
  • Water spins the other way down drains in Australia because of the Coriolis effect (Reading 5, question 2). Britannica: “the volume of water in the toilet is too small to be affected by Earth’s rotation (and the Coriolis force) in any appreciable way.”
  • Trade winds blow towards the east because they are called easterlies. Winds are named for where they come from (Reading 5; x6).
  • El Niño always means drought (Reading 8, part 2). The Bureau: “widespread drought does not occur with every event”.
  • La Niña always brings a wet south-east Queensland (Reading 8, part 2). From August 2020 to March 2021, during a La Niña, parts of south-eastern Queensland had below to very much below average rainfall (Bureau of Meteorology).
  • Most fresh water is in rivers and lakes (Reading 7, prediction; x8).

About the data and the models

  • The chart of today’s air (Reading 1) uses NOAA for nitrogen, oxygen and argon, and the Mauna Loa monthly mean for September 2026 (426.07 ppm) for carbon dioxide. September is near the yearly low at Mauna Loa.
  • The temperature graph (Reading 2) is the US Standard Atmosphere, 1976, a mid-latitude average. Its tropopause at 11 km lies between NOAA’s 6 km at the poles and 18 to 20 km at the equator, and above 86 km its heights are geometric. The layer bands use NOAA’s round boundaries.
  • The albedo chart (Reading 3) combines NSIDC, Penn State and NASA Earth Observatory. Forest combines Penn State’s coniferous (0.09 to 0.15) and deciduous (0.15 to 0.18) ranges.
  • The energy model (Reading 4) uses NASA’s rounded percentages. The Mauna Loa graph uses NOAA annual means for each decade, on an axis that starts at zero.
  • The circulation, conveyor and Pacific models (Readings 5 and 8) are schematic and not to scale.
  • Rainfall in Reading 5: the Bureau of Meteorology’s long-term means for Cairns Aero (station 031011, 1942 to 2026), Longreach Aero (036031, 1949 to 2026) and Birdsville Police Station (038002, 1892 to 2026), and for Brisbane Regional Office (040214, 1840 to 1994), which has the longest Brisbane record. The current Brisbane site (040913, from 1999) averages 1,056 mm a year. The November to April shares are our calculation from the monthly means. Bellenden Ker’s 8,068 mm is from the Bureau’s chapter in Year Book Australia 2005, over 31 years of records.
  • Temperatures in Reading 7: Brisbane Aero (040842, 1994 to 2026) and Roma Airport (043091, 1992 to 2026), chosen because their records cover similar years. Roma is about 300 m higher than Brisbane, which cools it a little, so compare the ranges rather than the averages.
  • The La Niña rainfall figure in Reading 8 is for eastern Australia from December to March, compared with the long-term average.
  • The D/H chart (Reading 6) gives Ryugu’s value converted from 165 × 10⁻⁶ in Piani and others (2023).
  • The fresh-water chart (Reading 7) uses the USGS table, from Shiklomanov (1993). Fresh water as about 2.5% of all water is our sum of the table’s fresh stores.
  • The links between water’s properties and Earth processes in the table (Reading 7) are standard textbook examples rather than quotes from one source.
  • Quotations in the screens are short excerpts checked against the source pages.

Where sources disagree

  • The Great Oxidation Event: about 2.3 billion years ago (ScienceDaily, on Lyons and others, 2014) or first significant oxygen about 2.43 billion years ago (Leeds, on Poulton and others, 2021).
  • Oxygen in the long low period, about 2 to 0.8 billion years ago: “~1-40% PAL” in the traditional view against “much lower than 1% PAL, and perhaps less than 0.1% PAL” (Olson and others, 2018).
  • Oxygen before cyanobacteria: Bush Heritage Australia says “Before cyanobacteria the air was only 1% oxygen”, far above the research values; we did not use it.
  • Layer boundaries: NOAA puts the stratosphere’s top at about 50 km and the mesosphere’s at 85 km; the 1976 standard puts them at 47 to 51 km and about 86 to 91 km. NOAA gives the thermosphere up to 2,000 °C; the standard assumes moderate solar activity and reaches about 726 °C at 500 km.
  • The Earth’s albedo: about 0.30 (NASA Earth Observatory) or 0.31 (Penn State).
  • Venus: 464 °C and 92 bars (NASA fact sheet) or about 467 °C and “93 times” Earth’s pressure (NASA). Mars carbon dioxide: 95.1% (NASA fact sheet); many textbooks give 95% to 96%.
  • The natural greenhouse effect: “more than 30 degrees” (NASA Earth Observatory) or about 33 °C (NASA).
  • Carbon dioxide in 2024: 423.9 ppm (WMO) or 422.8 ppm (NOAA), from different station networks.
  • The Hadley cell: sinking at about 30° (NOAA) or reaching “between 30 and 40 degrees” (Met Office).
  • How long water stays in the air: about 10 days (USGS; Britannica), 7 to 9 days (Science Learning Hub), or about 9 days if NASA’s “nearly 40 times a year” is divided out. Ocean residence time: 3,000 to 3,230 years (Britannica) or 3,000 to 3,500 years (Science Learning Hub). NOAA’s 1,000 years for the conveyor is the time for one trip, not a residence time.
  • Groundwater: 30.1% of fresh water (USGS table) or “approximately 22 to 30%” (NASA).
  • The origin of water: ESA says Rosetta favours asteroids; Hartogh and others (2011) found a comet that matches; Alexander and others (2012) favour CI chondrites; Piani and others (2020) argue Earth’s building blocks held enough; Piani and others (2023) put Ryugu-like material at about 3%. Britannica gives chemistry inside the planet as a rival view.
  • The Late Heavy Bombardment: the spike at 3.9 billion years from Apollo samples is now disputed; Bottke and Norman (2017) still see “a discrete episode” from about 4.2 to 3.5 billion years ago.
  • Europe’s mild winters: NOAA and the Met Office stress the Gulf Stream and the AMOC; Seager argues the atmosphere does most of the work and “The ocean heat transport contributes a small warming across the basin.”
  • The AMOC: about 15% weaker since the mid-twentieth century from a sea-surface fingerprint (Caesar and others, 2018); the IPCC is more confident about the projected decline this century than about the observed one.
  • The Millennium Drought: 2001 to 2009 in south-east Queensland (Seqwater, 2017), or from late 1996 to mid-2010 across southern Australia (a Seqwater fact sheet).
  • The lowest combined dam level in the drought: “approximately 20%” (Seqwater, 2017), but the Deputy Premier, Anna Bligh, told Parliament on 4 September 2007 that when the House last sat, dam levels were “just above 16 per cent” (Queensland Parliament, 2007). The often-quoted 16.7% could not be confirmed on an official page.
  • The northern wet season: October to April (Bureau of Meteorology rainfall maps), November to April (the Bureau’s monsoon page) or December to April in the Wet Tropics (CSIRO and Bureau of Meteorology, 2015).
  • Bellenden Ker: an average of 8,068 mm over 31 years (Bureau of Meteorology, 2005) or 8,140 mm over 38 years (Wet Tropics Management Authority).
  • Wivenhoe Dam’s flood storage: “a further 1.967 million megalitres” (Seqwater, 2021) or 1.45 million ML (van den Honert and McAneney, 2011). The desalination plant: up to 133 ML a day (Seqwater) or 125 ML a day (John Holland, part of the alliance that built it).
  • Reciprocal teaching: an effect size of 0.74 (Hattie) against .32 on standardised tests (Rosenshine and Meister, 1994) and .186 for whole-class reading-strategy programmes (Okkinga and others, 2018).

Answers at a glance

  • Reading 1: q2 the release of gases from rising magma; q4 it hardly reacts; q5 iron in seawater first; q6 the long summary.
  • Reading 2: q2 the top of the troposphere; q3 the ground heats the air; q4 ozone absorbs ultraviolet.
  • Reading 3: q2 a thinning over Antarctica each spring; q3 skin cancer, cataracts and plant damage; q4 open ocean.
  • Reading 4: q2 infrared from the surface; q3 absorb and radiate again; q5 Venus has far more gas.
  • Reading 5: q2 turning because the Earth spins; q3 dry air sinks at 30°; q4 moist trade winds pushed up over mountains close to the coast; q5 the ranges take the moisture and the ridge keeps the inland dry.
  • Reading 6: q2 vapour condensed as the surface cooled; q3 oxygen isotopes show contact with water; q4 too much heavy hydrogen.
  • Reading 7: q2 most moisture evaporated from open water; q3 the average time in one store; q4 the sea’s heat capacity. Phase sort: hail, sea ice and ice in a crack are solid; cloud droplets, groundwater and sap are liquid; humidity, volcanic water vapour and transpiration are gas.
  • Reading 8: q2 cold and salty water is dense; q3 nutrients return to the surface; q4 the trade winds weaken and the rain moves east; q5 a supply that depends less on rain.
  • Exit check: x1 water vapour, carbon dioxide and nitrogen; x2 photosynthesis; x3 stratosphere; x4 albedo falls; x5 absorb and reradiate; x6 the Coriolis effect; x7 not the main source; x8 about 69%; x9 ice floats; x10 cold, salty water sinks; x11 stronger trades, flooding.

Saved progress

Answers, roles and notes are saved only in this browser on this device. Nothing is sent anywhere.

References

  • Alexander, C. M. O’D., and others (2012). The provenances of asteroids, and their contributions to the volatile inventories of the terrestrial planets. Science, 337, 721–723.
  • Altwegg, K., and others (2015). 67P/Churyumov-Gerasimenko, a Jupiter family comet with a high D/H ratio. Science, 347, 1261952 (abstract via ESA).
  • ARPANSA and Cancer Council (n.d.). Cancer Council and ARPANSA stress importance of improved understanding as UV reaches extreme levels this summer (media release).
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