1. Chapter 2.2
Cycles of matter

2. There are 3 cycles:
Water cycle
Carbon and oxygen cycle
Nitrogen cycle

3. What is water cycle?
Without water, there would be no life. All living things need water to survive.
Cycle - is something that happens over and over in the same way.

4. Water molecule
Water- H2O

5. Water molecule

6. PRECIPITATION CONDENSATION
EVAPORATION
CONDENSATION
GRAPHIC ORGANIZER

7. What is water cycle?
Water cycle – is the repeated movement of water between Earth’s surface and the atmosphere (air). It is a process by which Earth’s water is recycled.

8. Terms related to the water cycle:
EVAPORATION
_____________ - the changing of a liquid to a gas
_____________ - changing of a gas to a liquid
_____________ - water that falls to Earth from the atmosphere
CONDENSATION
PRECIPITATION

9. Evaporation
Evaporation comes mainly from the oceans. The water first heated by the sun (Sun is the driving force to start the water cycle), and then changes to the water vapor. The rising of water vapor in the air is called evaporation.

10. Condensation
When water vapor rises, it cools. The water vapor loses heat. If the water vapor loses enough heat, it changes back to a liquid. The water vapor condenses to tiny water droplets. These tiny droplets form clouds.
A cloud is a collection of tiny water droplets.

11. Precipitation
Rain, snow, sleet or hail are different forms of precipitation. As the water droplets become bigger and bigger, they become too heavy to stay in the air. Gravity pulls the water droplets back to the Earth.

12. Water cycle diagram

13. Carbon and oxygen cycle
Carbon and oxygen are very important for life (they are related to breathing).
Carbon and oxygen are linked in one recycling process.

14. Animals takes in O2. Animals release CO2. Plant takes in CO2.
Plants produce
O2.
PHOTOSYNTHESIS

15. Carbon Cycle Diagram
Decomposers
Dead bodies

16. The carbon cycle
Producers take in CO2 gas from the air during photosynthesis. They will make their own food and release O2.
When producers and consumers die, decomposers will break down their dead bodies and return carbon back to the soil. Some decomposers release CO2 to the air.

17. The oxygen cycle
Oxygen cycles through ecosystems. Producers release oxygen as a result of photosynthesis. Animals will use oxygen to breathe.

18. Plants
If there were no more plants on Earth, the cycle would be stopped. Carbon and oxygen would no longer be recycled.

19. Human Impact - Fossil Fuels
Fossil fuels are non-renewable source of energy (they came from remains of plants and animals that died a long time ago).
Fossil fuels are:
Oil
Gas
Coal

20. Fossil Fuel (con’t.)
Fossil fuels (coal, oil, and gas) are major source of carbon.
When fossil fuels are being burned, they release a lot of CO2 into the atmosphere (air).
coal oil gas

21. What is nitrogen cycle?
Nitrogen Cycle - is the using and reusing nitrogen in an ecosystem (recycling of nitrogen).
Organisms need nitrogen for building proteins.

23. Nitrogen fixation
Nitrogen - fixing bacteria live on the roots of plants (legumes: beans, peanuts, and peas). They change the nitrogen gas to ammonia.

24. Nitrogen Cycle
Once the nitrogen gas has been changed to nitrogen compounds- ammonia, plants and animals use nitrogen to build proteins.
Decomposers break down animal waste and dead animals into ammonia.

25. Review Questions: What is evaporation?

26. What role do producers play in the carbon and oxygen cycles?

27. What is nitrogen fixation?

28. How human activities influence the carbon and oxygen cycles?

29. Where do some nitrogen-fixing bacteria live?

30. What are three major processes that occur (happen) during the water cycle?

31. What do decomposers after breaking down dead bodies or matter?

32. Section 2.2 Assessment
1a. Name and define the three major processes that occur during the water cycle. 1b. Defend this statement: the sun is the driving force behind the water cycle. 2a. Which two substances (materials) are linked in one recycling process? 2b. What role do producers play in the carbon and oxygen cycles? What role do consumers play in these cycles? 2c. How might the death of all the producers in a community affect the carbon and oxygen cycles?

33. Section 2.2 Assessment Con’t.
3a. Why do organisms need nitrogen? 3b. Outline the major steps in the nitrogen cycle. 3c. What might happen in a community if all the nitrogen-fixing bacteria died?