05 05 natural sciences u3a

Module 3A Travel and Tourism Activities 1 Look at these photos and answer the following questions orally The Greenhouse Effect In a greenhouse, light energy penetrates through the glass and falls upon the plants inside When it hits a surface, light energy becomes heat energy, and escapes into the atmosphere In the same way, the Earth is warmed by the sun and cools off by radiating heat energy (infrared radiation) back up towards space These heated gases then radiate part of the energy back down towards the Earth This process, called greenhouse effect, absorbs most of the harmful radiation before it reaches the Earth’s surface Measurements indicate an increase in the levels of greenhouse gases (carbon dioxide, methane, nitrous oxide, water vapour and chlorofluorocarbons) in the atmosphere Scientists refer to this as the enhanced greenhouse effect This increase is mainly due to human activities such as the burning of fossil fuels, deforestation, the use of fertilisers in agriculture, decomposition of garbage and the use of refrigerators and air conditioners This has led to global warming, which has changed the Earth’s atmospheric balance with effects in Polar Regions Part of the ice caps is melting, raising the height of the world’s oceans and producing floods in low-lying areas of the world 2 Answer these questions a Is the greenhouse effect a natural or man-made phenomenon? b Why is it called greenhouse? c What does the enhanced greenhouse effect lead to? English Toolkit - Natural Sciences Photocopiable © Ediciones Santillana S.A / Richmond 2011 What these photos show? Which of them may happen naturally and which can be caused by man? Are any of them common in your country? In other parts of the world? Module 3A d What changes has global warming brought about? e Which are the causes of global warming? 3 Find words or phrases that mean the same a to go up in strength or amount: b to become less warm: c the gaseous mass surrounding the Earth: d equilibrium: 4 Match the questions to the paragraphs b What is the greenhouse effect? c What is the cause of the increase in the greenhouse effect? Complete these ideas a The Earth cools off by b There is an increase in c This increase is called d Only man is responsible for e The change in the Earth’s atmospheric balance due to global warming f The melting of part of the ice caps produces 6 Find out more information about global warming and write a newspaper or magazine article or research on alternative sources of energy What are their advantages and disadvantages? English Toolkit - Natural Sciences Photocopiable © Ediciones Santillana S.A / Richmond 2011 a What is global warming causing?