Education is a long road that lasts a lifetime. Follow the WORLD MAKERS learning path to create a more equal, fair and sustainable world. Learning path L E A R N I N G S I T UAT I O N Water has properties that make it essential for life to exist. On Earth , water is found in three states: ice, at the poles and in glaciers; water, in seas and rivers; and steam, in geysers. Ice regulates the Earth's temperature by ref lecting part of the solar radiation that reaches it. Recent studies show a significant loss in the surface area and thickness of existing ice sheets. We must send an SOS to prevent this and the serious consequences it will have on our planet. You are going to make a video to spread this message. Take act ion When making your video, you should use all the information you have studied in this unit about states of matter and changes in state. Your scientific knowledge will strengthen your message and help you to complete your challenge. Target 13.3: "Improve education , awareness-raising and human and institutional capacity on climate change mitigation , adaptation , impact reduction and early warning." States of matter 2 How many states is matter found in? How can we make matter change from one state to another? When matter changes state, does it experience a physical or chemical change? WORK WITH THE IMAGE A wide range of living things live at the poles. How will the melting ice affect their existence? Will they be able to survive? WORK WITH THE IMAGE Technology is enabling us to construct more comfortable buildings that use less energy. One of these advances is reflective roofs. They can reflect up to 70 % of the solar energy that reaches them and reduce the temperature inside by up to 10 °C. What colour is the reflective paint that is being applied to the roof ? Why has this colour been chosen? There is a sheet of insulating material under the paint. What would happen without this sheet? Compare the reflective roof with ice sheets. Why is the size of its surface area important? Why is its thickness important? IN THIS UNIT… Physical states of matter Kinetic theory and states of matter Gas laws Changes of state Kinetic theory and changes of state States of water and meteorology Make an SOS video: the Earth's ice is melting C HALLE NGE L E T ' S G E T S TA R T E D 33 32 STATES OF MATTER PHYSICS AND CHEMISTRY REVISION CHANGES IN STATE Matter can change from one physical state to another. For example, when we heat ice, first it turns into water and then into steam. If we cool the steam, the opposite changes occur. 1 In a table in your notebook, classify each substance as a solid, liquid or gas, according to its state at room temperature. wood natural gas oil water aluminium oxygen alcohol carbon dioxide sand 2 After leaving some ice cubes on a table for a while, they turned into water. How can this happen if they have not been heated? A C T I V I T I E S Matter that can be moved from one place to another without changing its shape or size. A solid does not need to be in a container. Solid Matter whose shape changes as it moves from one container to another. It always occupies the same volume. A liquid needs to be in a container, which can be open. Liquid water, oil , alcohol , etc. Matter whose shape and volume can be changed by squeezing, reducing or enlarging the container. A gas must be in a closed container. Gas ice, sugar, metals, etc. steam, air, butane gas, etc. 6. …it turns into ice. 5. …it turns into liquid water. If we put it in the freezer… 4. If we leave the steam to cool… COOLING 1. When we heat ice… HEATING 2. …it turns into water. If we continue heating it… 3. …it boils and turns into steam. 34 LEARNING SITUATION. THE CHALLENGE 1 THE SUSTAINABLE DEVELOPMENT GOALS 2 CORE SKILLS 3 Remember what you already know about the topic, your previous knowledge acquired in previous years, in other units or in your own daily life. Think about an everyday life situation and put yourself in the place of the characters who present it. Contribute to the achievement of one or several targets of the Sustainable Development Goals (SDGs). Analyse examples of SOLVED PROBLEMS, then apply what you have learnt to solve the activities. Think and express your analytical side by doing the different ACTIVITIES. Critical thinking. Discuss whether the information is true or not. In the TRUE OR FALSE? section, you will find suggestions for learning how to create truthful content and for deconstructing fake news and myths. Review in the initial REVISION section what you already know and relate this knowledge to what you are going to learn. Research, think and then answer the questions that will help you complete the challenge and acquire core skills. 2 Study water evaporation Materials Beaker of water Thermometer Stand Hot plate Stopwatch Stopwatch Stand Thermometer Beaker Hot plate Represent the data on a temperature–time graph. Look at the example in the table. Draw a graph Time (min) 0 1 2 4 6 8 10 12 Temperature (°C) 24 28 40 70 100 100 100 100 22 Answer. a) What is the boiling point of water? b) How do you know? 23 Could water reach a temperature above 100 °C? Why? 24 Why must the thermometer not touch the bottom of the beaker? What would it record in this case? 25 What will happen if we turn the heat of the hot plate up or down? Can the thermometer record a temperature above 100 °C? Explain your answer. Conclusions Hang the thermometer so the bulb is in the middle of the water. Turn on the hot plate. Start the stopwatch. Write down the temperature at different times. Record the information in a table. Continue to record the time and temperature for a few more minutes, while the water is boiling. Steps 1 2 3 43 Do experiments and carry out simple practical activities. Complete the steps by applying what you have learnt. Acquire essential knowledge from content explained in a very clear way and with strong visual support: photos, drawings, diagrams, etc. ESSENTIAL KNOWLEDGE 4
RkJQdWJsaXNoZXIy