The greenhouse effect

Suggested simplified discussion for remedial lesson in grade 7 science

1. THE GREENHOUSE EFFECT Simplified Explanation for Remedial Lesson in Grade 7 Science MA. RACHEL B. ESPINO Buhatan National High School Purok Marcos, Buhatan, Sorsogon, City

2. The GREENHOUSE EFFECT is a natural process that warms the Earth’s surface. To understand the greenhouse effect, we need to understand how a real greenhouse works

3. How a greenhouse works A greenhouse is a house made of glass. It has glass walls and a glass roof. People grow vegetables, flowers and other plants in them. A greenhouse stays warm inside even during cold season.

4. In temperate countries, a greenhouse is used to grow seedlings in the late winter and early spring and later, planted in the open field when the weather is warmer.

5. Greenhouses also protect plants from weather phenomena such as snowstorm or duct forms. In tropical countries like ours, greenhouses are used by commercial plant growers to protect flowering and ornamental plants from harsh weather conditions and insect attack .

6. How a greenhouse works Greenhouses allow sunlight to enter but prevent heat from escaping. The transparent covering of the greenhouse allows visible light to enter without obstruction. It warms the inside of the greenhouse as energy is absorbed by the plants, soil and other things inside the building. Air warmed by the heat inside is retained in the building by the roof and walls. The transparent covering also prevents the heat from leaving by reflecting the energy back into the walls and preventing outside winds from carrying it away.

7. Earth’s atmosphere does the same things as the greenhouse. Greenhouse gases in the atmosphere do what the roof of the greenhouse does.

8. During the day, the Sun shines through the atmosphere. The Earth’s surface warms up in the sunlight. At night, Earth’s surface cools, releasing the heat back into the air, but some of the heat is trapped by the greenhouse gases in the atmosphere, they absorb the energy coming from the Earth’s surface, keeping the Earth’s temperature suitable for life on Earth. This process by which the Earth’s atmosphere warms up is called ‘greenhouse effect’

9. The greenhouse effect is a natural process and it warms the Earth. Without the greenhouse effect, Earth would be very cold, too cold for living things to live.

10. However, if the greenhouse effect is too strong, Earth gets warmer and warmer. Too much carbon dioxide and other greenhouse gases in air can make the greenhouse effect stronger which would result to global warming.

11. Sources of Greenhouse Gases

12. CARBON DIOXIDE CARBON DIOXIDE (CO 2 ) is naturally produced when people and animals breathe. Plants take in and use CO 2 to produce their own food. When food is oxidized in the cells, CO 2 is given off as a waste product. It is also returned to the air as a product of combustion and decomposition.

13. METHANE METHANE (CH 4 ) is emitted by natural sources such as wetlands, as well as human activities such as leakage from natural gas systems and the raising of livestock.

14. OZONE (O 3 )is created by sunlight acting on oxides of nitrogen and volatile organic compounds in the air. There are thousands of types of sources of these gases. Some of the common sources include gasoline vapors , chemical solvents, combustion products of fuels and consumer products .

15. CLOROFLUOROCARBONS CFC’s are anthropogenic compounds that have been released into the atmosphere since 1930s in various applications such as in air-conditioning, refrigeration, blowing agents in foams, insulations and packing materials, propellants in aerosol cans and as solvents.

16. WATER VAPOR WATER VAPOR is the gaseous phase of water. It is one state of water within the hydrosphere. Water vapor can be produced from the evaporation or boiling of liquid water or from sublimation of ice .

17. NITROUS OXIDE NITROUS OXIDES is naturally present in the atmosphere as part of the nitrogen cycle and has a variety of natural sources. However, human activities such as agriculture, fossil fuel combustion, waste water management and industrial processes are increasing the amount of nitrous oxide in the atmosphere.

18. Due to the increasing use of fossil fuels, burning of forest lands to increase agricultural production, decaying of agricultural products and other human activities, the concentration of greenhouse gases in the atmosphere has been increasing, resulting in an ‘enhanced greenhouse effect’ which is often referred to as global warming.

19. GLOBAL WARMING Global warming is the term used to describe a gradual increase in the average temperature of the Earth’s atmosphere and its oceans, a change that is believed to be permanently changing the Earth’s climate.

20. Effects of global warming

21. Melting of Polar Ice Caps Ice is melting worldwide especially at the Earth’s poles. This includes mountain glaciers, ice sheets covering West Antarctica and Greenland and Arctic sea ice.

22. Decline of endemic animal and plant species Philippine Tarsier Tarictic Hornbill Philippine Eagle Philippine Spotted Deer Mindanao Bleeding Heart

23. Nephentes ventricosa Waling-waling Camia Ilang-ilang Basingtonia asiatica

24. Increase precipitation Precipitation (rain and snow fall) has increased across the globe on average.

25. Increase population of pests

26. Decline in agricultural harvest

27. Droughts and floods become common

28. Decrease supply of clean drinking water

29. Spread of Diseases

30. Hurricanes and typhoons are stronger and more frequent

31. Species that depend on one another may become out of sync Species that depend on one another do not work at the same time and speed. For example, plants would bloom earlier than their pollinating insects become active.

32. Change in the Natural Ecosystems Ecosystems will change. Some species will move farther north or become more successful; others won’t be able to move and become extinct.

33. REFERENCES Science Learners Material Integrated Science I, DepEd , Quezon City: Vibal Publishing House, 2009 http://environment.nationalgeographic.com/environment/global-warming/gw-effects / http://climatekids.nasa.gov/greenhouse-effect /

34. SUGGESTED VIDEOS Global Warming: A Way Forward: Facing Climate Change  https:// www.youtube.com/watch?v=pAA7FEqYTjA Six Degrees Could Change The World https:// www.youtube.com/watch?v=R_pb1G2wIoA LOREN LEGARDA: BUHOS, A Climate Change  Documentary https:// www.youtube.com/watch?v=ESW_S8ZHS80 PANAHON NA! Ang Hamon sa Pinoy at Climate Change https:// www.youtube.com/watch?v=iOjyCHA_PeA