1. My Pals are Here! Science © 2008 Marshall Cavendish (Singapore) Private Limited © 2009 Marshall Cavendish International (Singapore) Private Limited

2. Questions to think about… How is water used in human life processes? How is water used in animal and plant life processes? Why is water precious? What are the different ways to conserve water? © 2009 Marshall Cavendish International (Singapore) Private Limited

3. Water in human life processes Water is important for many of our daily activities. Let us take a look at a few examples of how we use water. We use water to shower and clean ourselves. © 2009 Marshall Cavendish International (Singapore) Private Limited

4. Water in human life processes We use water to drink and cook. © 2009 Marshall Cavendish International (Singapore) Private Limited

5. Water in human life processes We use water to wash the laundry. © 2009 Marshall Cavendish International (Singapore) Private Limited

6. Water in human life processes We use water to water our plants. © 2009 Marshall Cavendish International (Singapore) Private Limited

7. Water in human life processes We use water to put out fires. © 2009 Marshall Cavendish International (Singapore) Private Limited

8. Water in human life processes We use water for sports. © 2009 Marshall Cavendish International (Singapore) Private Limited

9. Water in human life processes We use water in farming. © 2009 Marshall Cavendish International (Singapore) Private Limited

10. Water in human life processes We use water to make our surroundings more beautiful. Can you think of more ways in which we use water? © 2009 Marshall Cavendish International (Singapore) Private Limited

11. Water in animal and plant life processes Water plays various roles in animal processes too. For example, the gills of a fish take in oxygen that is dissolved in the water around it for respiration. © 2009 Marshall Cavendish International (Singapore) Private Limited

12. Water in animal and plant life processes In the circulatory system of animals, blood transports water and dissolved food to all parts of the body. © 2009 Marshall Cavendish International (Singapore) Private Limited

13. Water in animal and plant life processes In the digestive system of animals, most of the water is removed from food in the large intestine, to be used again by the body. large intestine © 2009 Marshall Cavendish International (Singapore) Private Limited

14. Water in animal and plant life processes Water also plays a large part in plant life processes. For example, in the transport system of plants, xylem tubes carry water and mineral salts from the roots to the other parts of the plants. © 2009 Marshall Cavendish International (Singapore) Private Limited

15. Water in animal and plant life processes Water is needed for photosynthesis in plants so that it can make food. © 2009 Marshall Cavendish International (Singapore) Private Limited

16. Water in animal and plant life processes Water makes up a large part of the sap in the centre of most plant cells, helping the cells stay firm. sap of a plant cell © 2009 Marshall Cavendish International (Singapore) Private Limited

17. Water in animal and plant life processes A seed will start to germinate when it lands on a place with sufficient warmth and water. © 2009 Marshall Cavendish International (Singapore) Private Limited

18. Water is precious About 70% of the Earth’s surface is covered with water. However, only about 3% of the water on Earth suitable for human consumption. © 2009 Marshall Cavendish International (Singapore) Private Limited

19. Water is precious When harmful substances get into water, it is longer fit for drinking and for use in most of our daily activities. Animals, plants and humans can die if they take in such polluted water. Human activities are the main cause of water pollution. © 2009 Marshall Cavendish International (Singapore) Private Limited

20. Water is precious Littering and dumping o Littering and dumping of waste is a common cause of water pollution. o When waste decays in water, it contaminates the water by producing harmful substances that cause further water pollution. o Furthermore, the sight of waste floating in the water is an eyesore. © 2009 Marshall Cavendish International (Singapore) Private Limited

21. Water is precious Oil spills o Oil spills may occur in accidents involving big ships that transport oil. o These often result in large amounts of oil being released into the sea. o However, oil spills usually occur through everyday activities such as when tankers load and unload the oil they are carrying, or when waste engine oil is released from ships. © 2009 Marshall Cavendish International (Singapore) Private Limited

22. Water is precious Oil spills o Oil is also released into the sea at oil platforms, where drilling for oil takes place. o When oil gets into water bodies, it spreads over the surface of the water. o The oil stops oxygen from reaching the animals and plants living in the water. o These living things will die if the oil spill is not cleared quickly. © 2009 Marshall Cavendish International (Singapore) Private Limited

23. Water is precious Oil spills o The oil also sticks to the feathers of seabirds and the fur of sea mammals. o This makes the feathers and fur clump together. o The animals will no longer be able to swim, fly or float. o This also affects their ability to keep warm and may even cause them to freeze to death. © 2009 Marshall Cavendish International (Singapore) Private Limited

24. Water is precious Deforestation o Deforestation is the clearing of forests by cutting or burning. o When the forest is removed, the soil becomes exposed. o Without the roots of plants to hold on to the soil, wind and rain will move large amounts of soil from the ground into nearby water bodies, polluting the water. © 2009 Marshall Cavendish International (Singapore) Private Limited

25. Water is precious Deforestation o Water polluted by soil becomes cloudy. o As a result, sunlight cannot reach the water plants. o Thus, the water plants cannot photosynthesise and will eventually die. o Other living things that depend on these plants for food will also be affected. © 2009 Marshall Cavendish International (Singapore) Private Limited

26. The different ways to conserve water Although water is always recycled through the water cycle, the water may not be enough for all living things if it is used carelessly or if a lot of it becomes polluted. Thus, it is important to use water carefully so that it lasts a long time. This practice is called the conservation of water. © 2009 Marshall Cavendish International (Singapore) Private Limited

27. The different ways to conserve water Reducing o Take a shower instead of a bath. o Do your laundry in the washing machine only when you have a full load. o Instead of rinsing dishes under a running tap, do it in a basin of water. You can help to conserve water by practising the 3 Rs – reducing, reusing and recycling. © 2009 Marshall Cavendish International (Singapore) Private Limited

28. The different ways to conserve water Reusing o You can collect water that was used to rinse rice and vegetables to water plants. o Rainwater can be collected and used to wash floors and walls. o Water from the washing machine can be collected after the final rinse, for such purposes too. © 2009 Marshall Cavendish International (Singapore) Private Limited

29. The different ways to conserve water Reusing o You can collect water that was used to rinse rice and vegetables to water plants. o Rainwater can be collected and used to wash floors and walls. o Water from the washing machine can be collected after the final rinse, for such purposes too. © 2009 Marshall Cavendish International (Singapore) Private Limited

30. The different ways to conserve water Recycling o Some factories here recycle their water by removing waste materials in the water using purifying systems. o The recycled water is used by the factories to wash things, cool their machines and for other purposes. o These factories can save thousands of dollars on water bills by recycling water. © 2009 Marshall Cavendish International (Singapore) Private Limited

31. The different ways to conserve water Recycling o The Jurong Industrial Waterworks recycles treated waste water from the Ulu Pandan Sewage Treatment Works. o The recycled water from the waterworks is stored in two reservoirs, Jalan Buroh and Penjuru. o This water is then piped to factories for their use. © 2009 Marshall Cavendish International (Singapore) Private Limited

32. The different ways to conserve water When reducing, reusing and recycling are practised, we can keep clean water for other important uses like drinking and cooking. © 2009 Marshall Cavendish International (Singapore) Private Limited

33. The different ways to conserve water Water rationing exercises o During a water rationing exercise, water supply to homes is cut off temporarily. o Our government carries out these exercises to let you experience the inconvenience of a water shortage. o It hope that by doing so, you will be reminded to use water carefully. o Such an exercise also teaches you what to do it you experience water shortage in the future. © 2009 Marshall Cavendish International (Singapore) Private Limited

34. The different ways to conserve water Campaigns o ‘Save Water’s campaigns are also carried out to remind everyone that water is a limited resource. o They make us realise that water conservation is the responsibility of every Singaporean. © 2009 Marshall Cavendish International (Singapore) Private Limited

35. My Pals are Here! Science © 2008 Marshall Cavendish (Singapore) Private Limited © 2009 Marshall Cavendish International (Singapore) Private Limited