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Pi. XL Club The Pi. XL Club The Pi. XL Club The Pi. XL Club The Pi. XL Club The Pi. XL Club The Pi. XL Club The Pi Club The Pi. XL Club The Pi. XL Club The Pi. XL Club The Pi. XL Club The Pi. XL Club The Pi. XL Club The Pi. XL Club The Pi. XL Cl The Pi. XL Club The Pi. XL Club The Pi. XL Club The Pi. XL Club The Pi. XL Club The Pi. XL Club The Pi. XL Club The Pi. XL Club Th Pi. XL Club The Pi. XL Club The Pi. XL Club The Pi. XL Club The Pi Club The Pi. XL Club The Pi. XL Club The Pi. XL Club The Pi. XL Cl The Pi. XL Club The Pi. XL Club The Pi. XL Club The Pi. XL Club Th Pi. XL Club The Pi Club The Pi. XL Club The Pi. XL Cl The Pi. XL Club The Pi. XL Club Th This resource is strictly for the use of member schools for as long as they remain members of The Pi. XL Club The Pi It may not be copied, sold nor transferred to a third party or used by the school after membership ceases. Club The Pi. XL Club The Pi. XL Cl Until such time it may be freely used within the member school. The Pi. XL Club The Pi. XL Club Th Pi. XL Club The Pi All opinions and contributions are those of the authors. The contents of this resource are not connected with Club The Pi. XL Club The Pi. XL Cl The Pi. XL Club The Pi. XL Club Th nor endorsed by any other company, organisation or institution. Pi. XL Club The Pi Club The Pi. XL Club The Pi. XL Cl www. pixl. org. uk The Pi. XL Club Ltd, Company number 07321607 The Pi. XL Club The Pi. XL Club Th Pi. XL Club The Pi Club The Pi. XL Club The Pi. XL Cl DTT Booster WJEC Separate Science Reformed Specification THERAPY Topic – The Ever-Changing Earth Commissioned by The Pi. XL Club Ltd. February 2016 © Copyright The Pi. XL Club Ltd, 2016

How to deliver the DTT Booster • Administer the short diagnosis test. • Mark the test (peer assess) • Work through therapy slides completing the model questions and answers. • Complete the question slides for students to self assess. • Administer the final test (peer assess)

The Ever-Changing Earth Atmosphere: Most lies within 10 km of the surface, the rest is within 100 km Crust (lithosphere): Solid rock, 6 km beneath oceans, 35 km beneath land Broken Crust The crust (lithosphere) is broken into huge pieces called plates. There are 7 or 8 major plates and many minor plates. We know where the edges of the plates are (plate boundaries) because that is where we have earthquakes and volcanoes. Core: Made of iron Outer core is liquid iron Inner core is solid iron Radius is 3500 km Mantle: Behaves like a solid Can flow very slowly Is about 3000 km deep! Model Question: How do we know where plate boundaries are? Model Answer: Earthquakes and volcanoes are found at plate boundaries. . CLICK to reveal MODEL ANSWER

The Ever-Changing Earth The Changing Earth Moving Continents: The Earth’s crust and upper mantle are cracked into a number of pieces tectonic plates. These are constantly moving - just very slowly. Motion is caused by convection currents in the mantle, due to heat from radioactive decay. Pangea In 1912, Alfred Wegener published his theory of Continental Drift. Wegener thought that all of the continents had once been joined in a supercontinent called Pangea and had drifted apart over millions of years. Wegener’s evidence for continental drift: The same types of fossils (animals and plants) and matching rock formations are found on opposite sides of oceans. The shape of the east coast of South America fits the west coast of Africa, like pieces in a jigsaw puzzle. https: //sergimartin. files. wordpress. com/2010/08/pangea. gif When Wegener came up with his theory of Continental Drift, other scientists did not believe him as he couldn’t explain how or why the tectonic plates move. Model Question: What evidence did Wegener use for his theory of Continental drift? Model Answer: Continents fit like jigsaws Same rocks and fossils on opposite sides of oceans. CLICK to reveal MODEL ANSWER

The Ever-Changing Earth The Earth is 4, 500 million (4. 5 billion) years old. The gases in the atmosphere have changed over time. When the first atmosphere formed it was very different to how it is today. Model Question: Explain what has happened to the level of CO 2 in the atmosphere in the last 4. 5 billion years. Model Question: Lots at first CLICK to reveal MODEL ANSWER from volcanoes. Reduced to very small amount by photosynthesis. Evolution of the Earth’s Atmosphere (4. 5 billion years) Phase 1 (1 st billion yrs) Phase 2 Phase 3 Volcanoes = Steam & CO 2 Green Plants, Bacteria & Algae = Oxygen Ozone Layer = Animals & Us Volcanoes kept erupting giving out Steam and CO 2. The early atmosphere was nearly all CO 2. The earth cooled and water vapour condensed to form the oceans. Green plants, bacteria and algae photosynthesised in the oceans. Green plants steadily converted CO 2 into O 2 by the process of photosynthesis. Nitrogen released by denitrifying bacteria Plants colonise the land. Oxygen levels steadily increase. The build up of O 2 killed off early organisms - allowing evolution of complex organisms. The O 2 created the Ozone layer (O 3) which blocks harmful UV rays from the sun. Virtually no CO 2 left.

The Ever-Changing Earth The Earth’s Atmosphere Today Gas Formula % Nitrogen N 2 78 Oxygen O 2 21 Carbon dioxide CO 2 0. 04 Argon Ar 0. 9 Model Question: Label the pie chart to show the percentage of different gases in the air. Model Answer: Oxygen Argon CLICK to reveal MODEL ANSWER Nitrogen Gas Test Observation Oxygen Glowing splint Relights Carbon Bubble Dioxide through limewater Turns milky Gas Nitrogen Oxygen Argon Neon Use Food packaging Welding Light bulbs Signs Where it comes from Air many of the Air gases we use Air come from air We can separate different gases from the air because they have different boiling points. A process called fractional distillation is used to obtain the different gases.

The Ever-Changing Earth Carbon Dioxide, CO 2, Levels: Millions of years ago, carbon was locked into fossil fuels and buried under the Earth. In the last 200 years we have started burning fossil fuels and the carbon is released as CO 2. Process Effect on CO 2 in the atmosphere Respiration Increases (living things breathe out CO 2) Combustion Increases (burning forms CO 2) Photosynthesis Acid Rain Fossil fuels (especially coal) contain sulfur. When the fossil fuel burns the sulfur reacts with oxygen to form sulfur dioxide, SO 2. The SO 2 reacts to form acid in clouds and this falls as acid rain. Acid rain harms aquatic life, erodes limestone and can kill trees. Decreases (plants take in CO 2 and give out oxygen) Model Question: Why is the amount of CO 2 in the atmosphere increasing? Model Answer: The carbon that was locked into the fossil fuels millions of years ago is being released as CO 2 now that we are burning lots of fossil fuels. CLICK to reveal MODEL ANSWER The amount of CO 2 in the atmosphere is very small but small increases make a big difference. Greenhouse Effect: Gases like CO 2 trap heat and stop it escaping into space and keep the Earth warmer than it would be. Global Warming: Increasing CO 2 levels means increased greenhouse effect and this can lead to climate change. Solutions: • Burn less fossil fuels (use renewable energy). • Walk instead of using a car. • Turn off lights and appliances when not in use.

The Ever-Changing Earth - Questions 1. What is the core of the Earth made from? 2. Draw a simple sketch of the Earth’s structure and label each part with a description. 3. Give three pieces of evidence for Wegener’s theory of Continental Drift. 4. Name the main gases in today’s atmosphere. What are their percentages? 5. How did photosynthesis affect the composition of the atmosphere? 6. Why has the amount of carbon dioxide in the atmosphere been increasing in the last 200 years? 7. Why is an increase in the amount of carbon dioxide in the atmosphere a problem? 8. How does acid rain form?

The Ever-Changing Earth - Answers 1. What is the core of the Earth made from? Iron 2. Draw a simple sketch of the Earth’s structure and label each part with a description. 3. Give three pieces of evidence for Wegener’s theory of Continental Drift. Continents fit like jigsaws, same rocks and fossils on opposite sides of oceans. 4. Name the main gases in today’s atmosphere. What are their percentages? Nitrogen – 78%; Oxygen – 21%; Argon – 0. 9%

5. How did photosynthesis affect the composition of the atmosphere? Produced oxygen. Reduced carbon dioxide. 6. Why has the amount of carbon dioxide in the atmosphere been increasing in the last 200 years? Increased burning of fossil fuels releasing carbon that has been locked up in fossil fuels for millions of years. 7. Why is an increase in the amount of carbon dioxide in the atmosphere a problem? Enhances Greenhouse Effect. Increased global warming (climate change etc). 8. How does acid rain form? Sulfur in coal burns and forms sulfur dioxide which forms acid rain in clouds.

Final test DTT Booster • Students now complete the final test (peer assess). • Compare this to what they achieved in the diagnostic test.