Solids, liquids and gases

Transcription

1 Solids, liquids and gases Duration 60 minutes Lesson overview Students share what they know about the three states of matter solid, liquid and gas and consider some of their scientific properties. They explore how matter can change states physically, through heating and cooling, and how particles move. Objectives Students will be able to: sort and classify common examples of solids, liquids and gases identify common properties of the three states of matter demonstrate how states of matter can change with changes in temperature demonstrate how particles move with changes in temperature Curriculum connections - Science Big idea materials can be changed through physical and chemical processes Content physical ways of changing materials Curricular competencies observe objects and events in familiar contexts ask questions about familiar objects and events sort and classify data and information using drawings, pictographs and provided tables make and record observations compare observations with those of others communicate observations and ideas using oral or written language, drawing or role-play What you will need ice cube in a clear bowl, two clear glasses, kettle and water Solids, Liquids And Gases Cards chart paper and markers Solids, liquids and gases lesson Grade 2 Page 1 of 6

2 Preparation Review the Solids, Liquids And Gases cards and Lesson Notes. Prepare the cut-out cards for activity 1 using the Solids, Liquids And Gases Cards. Depending on the number of students in your class, you may need two sets of cards. The activity will work with duplicate cards. Prepare the materials for activity 3 and set them up in a space where students can easily see. - Have the ice cube sitting in a clear bowl, have a glass filled with water at room temperature, and have the kettle filled with water and ready to turn on. - Have a clear glass or mug beside the kettle for pouring the hot liquid into. Ensure the ice cube has begun to melt. - Ensure the kettle and glass (or mug) are in a safe place, out of reach of students. Prepare three pieces of chart paper, labelled with the three states of matter. For activity 4, ensure students can move around between desks/tables safely. Consider trying this activity outside or in the gym, using hula hoops or other boundaries to create different sized spaces for movement. Lesson notes This lesson provides students with an opportunity to share what they already know about solids, liquids and gases, and then further explores how matter can change states physically with heating and cooling (using water as an example). Matter is anything that takes up space and has mass and occurs in three commonly recognizable states: solids, liquids and gases. All of the states of matter have properties which describe specific composition and behaviours, and can be used for categorization. Solids have a definite shape and volume. The particles of a solid are in fixed positions, moving only slightly with other particles in close proximity. For young students, properties of solids include: keep their own shape and volume; do not flow; and can be cut. Liquids have a definite volume and assume the shape of their container. The particles of a liquid are closely spaced, so their motion is random but limited. The particles can slip past and collide with other particles in close proximity. For young students, properties of liquids include: take the shape of their container; keep the same volume; flow easily (can be poured); and cannot be cut. Gases assume the shape and volume of their container. Particles of a gas are separated from each other; move in straight lines and in a completely random manner. The particles change direction only when they collide with each other or the container. For young students, properties of gases include: take on the size and shape of their container; do not keep the same volume because they can expand; flow easily; and cannot be cut. Water provides an example of physical changes across all three states, where there is a change in the energy and movement of molecules, but the structure of the molecules does not change. Water molecules are the same in solid, liquid and gas states. Word list gas molecule liquid particle mass physical change matter properties Solids, liquids and gases lesson Grade 2 Page 2 of 6

3 Lesson activities Activity 1: Is it a solid, liquid or gas? (10 minutes) Display the three pieces of chart paper with the terms solid, liquid and gas (one on each piece of paper). Explain to students they are going to select a card with a picture of a solid, liquid or gas. All matter can be categorized into these three groupings. Hand out one of the Solids, Liquids And Gases Cards to each student. Have them look at their card silently on their own first, sounding out the word, and thinking about the following questions: - What is it? - Is it a solid, liquid or gas? - Why do you think so? Be prepared to explain to a partner! Have students travel around the room sharing their card with another student, discussing their answers with their partner. When one person has finished sharing, they should ask their partner Do you agree? If not, why? and give them a chance to respond. Have students repeat this process two to three more times with new partners. Activity 2: Properties of solids, liquids and gases (20 minutes) Using the cards, have students gather into three groups according to which they think their card represents (solids, liquids or gases). In their groups, have students share their reasons for what makes it a solid, liquid or gas, and then have each group place their cards on the prepared chart paper. Have students share their ideas about the properties of matter and write them on the prepared charts. Some key points to include on the chart papers are: - All matter takes up space and has mass (this should be on all charts). - Solids keep their own shape (this makes them unique). - Liquids and gases can change shape easily or flow. - Liquids take the shape of their container (they can be poured from one container to another of a different shape). - Solids and liquids always have the same volume or mass. - Gases expand and change volume to fill their container (they can take up more space). - You can see solids and liquids. You can t see most gases. - Solids can be cut (liquids and gases can t be cut, but they flow easily). Have students give some other examples of solids, liquids or gases they would find at school or home: - solids: clothes, many food products, pencils, computers, scooters - liquids: water, gasoline to fuel cars and school buses - gases: air, natural gas to heat homes or for gas stoves Solids, liquids and gases lesson Grade 2 Page 3 of 6

4 Activity 3: Demonstrating physical changes with water (20 minutes) Write the word water on the board and ask students: - What are some of the different ways we use water in our lives? - Pretend you have to describe water to someone who doesn t know what it is. How would you describe it? Explain to students that as a class, you are going to explore how water, as an example of matter, can change from one state to another. Turn the electric kettle on so the water is being heated during the first two examples. Show students the glass of water: - Is the water a solid, liquid or gas? - Review some of the properties to identify the correct state. Show the students the melting ice cube: - Is the ice a solid, liquid or gas? (It may be both a solid and liquid at this point.) - What had to happen to the water for it to become an ice cube? Show the students the kettle: - What is happening to the water inside the kettle? - Look at the steam coming from the kettle. Is the steam a solid, liquid or gas? - What had to happen to the water for it to become steam/vapour? Reinforce that by heating or cooling the liquid, the water is able to change states. This is an example of a physical change. Solids, liquids and gases lesson Grade 2 Page 4 of 6

5 Activity 4: Moving particles (10 minutes) Explain that all matter (solids, liquids and gases) is made up of particles so tiny our eyes can t see them. When many particles are held together, they form matter we can see with our eyes, like the water in the demonstration. Have students think about what happens to the particles when they are heated or cooled. Discuss their ideas as a class. - Review that as particles are heated, they start to move more quickly and move farther apart. When cooled, they move more slowly and often come closer together. Explain to students they are going to pretend to be particles changing states. Define a space in the class (like a carpeted area or a story corner) where everyone can group together closely and have students pretend to be particles: - Right now we are particles of a solid. Since the particles don t move very much, sway gently from side to side but don t move your feet. - Here comes the heat! Hold hands with your neighbour. As the particles get heated, they move a bit faster and move a bit farther apart as they become liquids. Move around the space but don t let go of your neighbours hands! - Here comes even more heat! What happens as particles are heated even more? They move farther apart and faster. Move around the whole room in any direction in a straight line until you bump into something and then change direction. Make sure you stay away from each other! - It s cooling time! What happens as the particles are cooled? They often move closer together and more slowly as they change from a gas to a liquid or a liquid to a solid. In slow motion, move around the room and then eventually back to the defined space used at the beginning. Have students sit back down to review and summarize as a class: - All matter is made up of tiny particles, and these particles are constantly in motion. How much they move is different for solids, liquids, and gases. - Particles in solids are packed closely together. The particles do not move around very much. - Particles in liquids are a little bit further apart from each other. The particles can slide past one another (easily flow). - Particles in gases are held together only by the shape of their container. The particles can move in all different directions to fill that container. Have students think about any questions they have. Listen to some of the questions and address these as a class or through follow up activities. Assessment Assess students prior knowledge through Activities 1 and 2. Assess student responses to questions during the demonstration and physical activities (activities 3 and 4). Solids, liquids and gases lesson Grade 2 Page 5 of 6

6 Extensions The Solids, Liquids And Gases Cards can be used in a number of different ways: - In small groups, play Go Fish but instead of matching pictures, match solids, liquids and gases. To extend the demonstration, use a simple balance scale to show that melting water maintains the same mass, even if it changes shape. Explore chemical changes using the example of fire. - Many students will be familiar with home fireplaces fuelled by wood or natural gas, or with campfires. These can be used as examples of chemical changes. The burning of natural gas and wood changes the composition of the materials and new chemical substances are formed (carbon dioxide, water and other products). Definitions gas: a state of matter; it s an air-like substance that fills whatever space or container it is confined to liquid: a state of matter; it s a fluid-like substance that takes on the shape of its container mass: how much there is of an object; it s a measure of how much matter an object has matter: anything that takes up space and has mass molecule: made up by chemically bonding two or more atoms of the same element or different elements; a molecule is also a particle particle: matter is made up of tiny particles that move physical change: where there is a rearrangement of molecules, but the rearrangement does not affect the internal structure of the molecules properties: characteristics, qualities or attributes of a thing solid: a state of matter; it s a firm or stable object that maintains its own shape Solids, liquids and gases lesson Grade 2 Page 6 of 6