Global warming melts the polar ice caps. Many glaciers are melting and shrinking, and they will continue to melt if the temperature increases. As a result, the sea level rises. This could cause flooding in cities located near the coast. Global warming also causes changes in the world’s weather patterns. Some places around the world experience extreme weather conditions such as powerful hurricanes, droughts and floods. These conditions destroy plants and can lead to a shortage of food. Unlike the burning of fossil fuels, the use of renewable energy sources that cause less pollution such as solar energy and wind energy is one way to reduce the production of carbon dioxide. Hurricane Flood Drought 46 Hands-on Science Primary 6
Did you know that human activities such as hunting and killing animals to use their body parts for different purposes can also contribute to global warming? • The horn of the rhinoceros is used in traditional medical practices. Some people believe it has healing properties. The animals are hunted and killed, and their bodies allowed to decompose. During decomposition, gases such as carbon dioxide are released. This increases the amount of carbon dioxide in the atmosphere which speeds up global warming. This also leads to an imbalance in food webs, with some animals becoming extinct. Humans also use plant parts for industrial purposes, such as to make paper, furniture and clothing. As more trees are chopped down, fewer plants will be left to take in carbon dioxide during photosynthesis. As a result, a greater amount of carbon dioxide is left in the atmosphere over time which will lead to global warming. Let’s Think Other than global warming, what are the other harmful effects on the environment of using plant parts on a large scale? Explain. • The skin of crocodiles and tigers has been used to make wallets, shoes, belts and carpets. • The musk of musk deer is used in perfumery. Human Impact on Chapter 3 the Environment 47
Human Activities and Environmental Conservation 3.2 The Earth provides us with natural resources, air, water and land that we need to survive. We need to care for the natural world around us, to keep it clean and healthy for it to continue to support life. Therefore, it is our responsibility to go green to conserve and keep our environment clean and healthy, including the air, water and land. This will ensure the natural resources are always available, not only to us but to our future generations as well. There are three ways to go green—reduce, reuse and recycle. Reduce, Reuse and Recycle Reduce is to limit the amount of materials we use or the waste we throw away. We use reusable containers or biodegradable bags for takeaway food or purchases to reduce the use of plastic. Things that are made of biodegradable materials, such as paper, are better for the environment as they can be broken down into tiny pieces overtime. Reuse is to find new ways for using old items that we might consider throwing away. Old towels can be reused as cleaning rags, and clothing can be donated to charitable organizations and be reused by others. Recycle is to remake unwanted materials into new products for alternative use. We can recycle an unwanted drinking bottle into a flower vase, instead of throwing it away as trash. We can recycle paper by converting it into decorative items. Reduce, reuse and recycle waste whenever possible. In some places, waste is first sorted out in a garbage collection center. Cans, glass and paper waste are recycled while the rest are buried in landfills. Get into groups. Walk around your school compound. • Observe whether there are recycle bins. • State the location of the recycle bins. • Do you think the locations of these bins are suitable? Why? • The bins are represented with different colors. What are the things that we can throw into each bin? Name three examples for each of the bins. • How do you create awareness for more pupils to encourage them to use the bins? • If there are no bins, what are the actions you could take? Share the ideas of your group with your classmates. Let’s Find Out! 48 Hands-on Science Primary 6
• Commute by carpooling or taking public transport. This is to reduce the use of fossil fuels, thus reducing air pollution. • In modern housing areas, domestic sewage is carried through pipes and drains to sewage treatment plants. The sewage is treated before disposal. • Throw rubbish into trash bags, tie them up properly and place them in covered rubbish bins. Clear the bins frequently to avoid overspills that attract pests. Organic waste is made into compost. Reducing Air, Water and Land Pollution Reforestation and Protecting the Natural Habitat for Wildlife We need to take steps to minimize pollution to protect our health as well as the Earth. Keep planting new trees to conserve the forests. This is to replace those we have cut down to make paper and for other purposes. If the forests can be reserved, animals and plants would be able to live in their natural habitat. Human Impact on Chapter 3 the Environment 49
Fill in the blanks. Some words can be used more than once. 1. The impact of human activities on the environment are the depletion of natural resources, and global warming. 2. Depletion of natural resources happens because resources are consumed faster than we can replace them. Some of the resources cannot be replaced because they are resources. 3. Pollution such as air pollution, pollution and pollution make our environment dirty and unhealthy. 4. Human activities such as by burning trees and the use of chlorofluorocarbons release harmful chemicals and gases into the air to cause pollution. 5. Excessive use of pesticides and improper disposal of garbage and waste cause pollution because the harmful chemicals and substances released cannot be broken down by bacteria in the soil. 6. The release of harmful and improper disposal of waste can also cause pollution when they go into the rivers, lakes and oceans. 7. Global warming occurs when activities such as deforestation and burning of fossil fuels release more and more into the atmosphere which increases world temperatures. 8. Global warming can cause extreme conditions such as floods due to the melting of the polar ice caps that causes sea levels to rise. 9. Reduce, reuse and are ways to go green and to cut down waste. 10. Other ways of conserving a healthy and balanced environment are reducing and planting new to conserve the forests. recycle land weather deforestation chemicals trees toxic non-renewable water pollution air carbon dioxide Let’s Scan 50 Hands-on Science Primary 6
Map It Out Any non-toxic, non-flammable, odorless manufactured chemicals in aerosol sprays, blowing agents for foams and packing materials The damage that is caused to air, water, land, etc. by harmful substances, toxins or waste Pollution A gradual increase in the overall temperature of the Earth’s atmosphere caused by the carbon dioxide that collects in the air Global warming A layer that protects the Earth from most of the ultraviolet rays from the Sun Ozone layer Chlorofluorocarbon Online Explain It QuickQuiz • Depletion of natural resources • Pollution - Air pollution - Water pollution - Land pollution • Global warming Human impact on the environment Impact of human activities on the environment Human activities and environmental conservation • Reduce, reuse and recycle • Reducing air, water and land pollution • Reforestation and protecting the natural habitat for wildlife Human Impact on Chapter 3 the Environment 51
Pendulum painting Paintings can be created without having to use a paint brush. We can make use of gravitational force to create a pendulum painting. You are required to build a pendulum to hold color paint in order to create a painting. The pendulum must be able to swing around while dripping the color paint onto a paper. Your pendulum must be at least 30 cm tall. Your painting must be at least 30 cm in length and width. Suggested materials: Color paints Sticky tape Clay • What is the aim of this activity? • What do you need to know to get started? • What are the aspects that you need to take note of in building your pendulum to help in creating the painting? ASK 119 STEM Activity Paper Yarn Craft sticks Plastic bottle Straws STEM Activity 119
• How does your pendulum look like? • In your opinion, how does the length of your pendulum affect the creation of your painting? • Other than the materials suggested, what other materials do you need? List them and prepare them. • Draw your pendulum model and list down the steps on how to make the model. IMAGINE PLAN 120 Hands-on Science Primary 6
• Create your pendulum based on what you plan. • Write down how your pendulum can help in creating the painting you want. • Are you satisfied with the pendulum you created? How do you modify it to make it better? • Test it again. • What is your conclusion about your improved version? Demonstrate to the class how your pendulum can create the painting you want. You can share with your classmates on all the paintings that have been created. CREATE IMPROVE PRESENT STEM Activity 121
DIY musical instrument Sound is vibrations that travel through a medium such as air or water. A musical instrument is an instrument created to make musical sounds. In principle, any object that produces sounds can be a musical instrument. You are required to make your own musical instrument with unwanted materials you can find. Discover if it works. Suggested materials: Box Scissors • What is the aim of this activity? • What do you need to know to get started? • What kind of musical instrument do you want to make, a wind instrument, a string instrument or another type of instrument? ASK 122 STEM Activity Rubber band Glue String Sticky tape 122 Hands-on Science Primary 6
• What is your possible instrument? • In your opinion, what kind of instrument is the best that you can make? • Other than the materials suggested, what other materials do you need? List them and prepare them. • Draw a design of your instrument and list down the steps on how to make it. IMAGINE PLAN STEM Activity 123
• Make your musical instrument based on the design in the planning stage. • Write down what you observed. • If it does not work well, how do you modify it to make it better? • Test it again. • What is your conclusion about the improved version? CREATE IMPROVE Present in class on how you made your musical instrument. You can present it via a PowerPoint presentation. At the same time, play a song using the instrument you made for your friends to enjoy! PRESENT 124 Hands-on Science Primary 6