Recycling The Carbon Cycle

Starter List the gases in the air. Nitrogen, oxygen, argon, carbon dioxide Which has the greatest percentage? N 2 -78%, O 2 – 21%, Ar – 1%, CO 2 – 0.04% What are the gases used for? Respiration, photosynthesis

Recycling – The carbon cycle Learning objectives Success criteria  State that as plants and animals grow they take in chemicals and incorporate elements from these into their bodies.  State that when animals and plants die and decay these elements are recycled.  Explain how carbon is recycled in nature. Student should be able to:  Draw a diagrammatic representation of the cycling of carbon in nature.

Why is carbon important? Proteins, fats and sugar all contain carbon. Life without carbon would be very different and might be impossible. Carbon is present in the atmosphere as carbon dioxide. What happens to the carbon in organisms when they die? The carbon from dead organisms can also form fossil fuels and sedimentary rocks such as limestone. These are long-term carbon stores. As dead matter decomposes, carbon is released back into the atmosphere in the form of carbon dioxide. Plants use carbon dioxide during photosynthesis to produce sugars. The carbon is then transferred to animals along food chains.

More on the carbon cycle Carbon is also recycled in the sea:  Marine organisms such as molluscs, corals and microscopic algae contain carbonates.  When these organisms die their shells collect on the sea floor.  Over millions of years they form a type of sedimentary rock called limestone.

Demonstration of carbon stores Watch the class demonstration and then complete worksheet B4h1 - Burning plant and animal materials 1.Blackened Ash, mainly carbon 2.Turns white/milky That carbon dioxide has been produced by the breakdown of sucrose, a carbohydrate 3. The limewater in flask B turns more white/milky than the limewater in flask A The carbon dioxide could only have come from our body (from respiration)

The carbon cycle Use the textbook to complete a copy of the carbon cycle Answer questions 1-10 from p84-85 of the textbook

Task 1. Digests it. 2. To build up new chemicals for growth. 3. It decays. 4. Nitrogen and carbon. 5. To make food for photosynthesis. 6. There would be no plants therefore no animals. 7. Respiration and burning/combustion. 8. Because a lot of wood is burnt. 9. Cities have lots of traffic pollution, so the atmosphere is more acidic, which attacks limestone causing it to crumble and parts of old building to become dangerous. 10. Limestone is made from the calcium carbonate shells of marine organisms – the shells are fossilised for millions of years, so ‘locking up’ the carbon.

Plenary

Recycling – The carbon cycle Learning objectives Success criteria  State that as plants and animals grow they take in chemicals and incorporate elements from these into their bodies.  State that when animals and plants die and decay these elements are recycled.  Explain how carbon is recycled in nature. Student should be able to:  Draw a diagrammatic representation of the cycling of carbon in nature.