Heat Stage 2 Science Unit Duration: 10 Weeks

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Heat Stage 2 Science Unit Duration: 10 Weeks Physical World Learning Across the Curriculum: Aboriginal and Torres Strait Islander histories and cultures Asia and Australia's engagement with Asia Ethical understanding Personal and social capability Information and communication technology capability Civics and citizenship Sustainability Intercultural understanding Difference and diversity Critical and creative thinking Numeracy Work and enterprise Outcomes ST2-6PW identifies ways heat is produced and that heat moves from one object to another. ST2-12MW identifies that adding or removing heat causes a change of state between solids and liquids. Topic Description Students will investigate the role of heat in the physical world. They will explore the different types of heat transmission: conduction, convection, and radiation. Students will learn about what produces heat, how, and why? They will discuss the uses of heat and develop an understanding of changing states of matter through heating and cooling. Content • • • • • • • • A change of state between solid and liquid can be caused by adding or removing heat. (ACSSU046) Students: describe some everyday situations where solids and liquids change state by adding heat (heating) or removing heat (cooling) predict and observe the effects of adding heat or removing heat on a variety of everyday solids and/or liquids, e.g. butter, chocolate and water describe how scientific knowledge about the effects of heating and cooling is used by people in their everyday life, e.g. the types of clothes worn, the packaging and preparation of food and everyday devices, e.g. freezers, irons or cooktops Heat can be produced in many ways and can move from one object to another. (ACSSU049) Students: identify in their environment some different ways in which heat is produced, e.g. by electricity, burning (chemical) and friction (motion) observe the effects of heat moving from one object to another, e.g. the feeling when hands are placed in warm or cold water describe how people use scientific knowledge in their work and everyday life to control the movement of heat from one object to another, e.g. a pot holder, insulated bags or thermos. Week 1 Week 2 Term 2 Unit Overview – 9 weeks Introduction to Heat • What do they already know • Introduce the different ways to keep warm. • How can we generate heat? How do animals keep warm? • Identify heat sources and how heat moves. Introduce concepts of radiation, convection and conduction. Heat Production • • • Week 3 Week4 Week 5 Week 6 Week 7 Week 8 Combustion (wood, gas, coal), need fuel and oxygen to burn things, discuss things that are flammable and not flammable Friction is a form of heat – if you rub two rough things together you produce a lot of friction, carpet burn example Radioactivity – sunburn, radioactive energy produced by the sun is capable of burning you, solar panels collect radiation from the sun and turn it into electrical energy Thermometers • What is a thermometer? Why do we use them? What does temperature mean? What are degrees (important points on the thermometer)? • Thermometer experiment Heat Transmission • 3 ways that heat can be transmitted: convection, conduction, radiation. • Conduction experiment Heat Sources • Sources of heat in our homes and classroom • Do items that produce heat in the classroom produce their own heat or are they heated by something else? • Look at electricity, friction and burning as ways of producing heat • Draw sources of heat in their home in a map. Insulation • Things that conduct heat poorly • Uses for insulators: pot holders to get things out of the oven, thermos to keep drink cold/hot, insulation in houses to keep house at a nice temperature • Experiment: put ice cubes Keeping Warm • Explore how heat can be retained using different materials Changing States • Overview of the three states of matter: solid, liquid, gas • The role that heat plays in changing the state of substances – gases are in their gas form because of heat, if we were to remove heat, these substances would return to their liquid form • Water/ice/steam • Butter as a liquid and solid Week 9 • Experiment changing between liquid and solid. Assessment Teaching & Learning Activities Lesson 1: Introduction to…Why do we need heat? Take home message: (WALT) learn the many ways that we can generate heat to keep warm. • • • • • • • • • • • Introduction: Introduce unit topic: Heating up and changing states KWL chart to find out what students already know about the topic. How do animals keep warm? Watch short clips of snow monkeys and penguins keeping themselves warm in harsh conditions. https://www.youtube.com/watch?v=OL7O5O7U4Gs http://www.discovery.com/tv-shows/other-shows/videos/discovery-atlas-snow-monkeys/ Discuss what the animals did to keep warm. Why did they do it that way? Guided Questions: Why do people need heat? How do we measure heat? What sources of heat do we rely on to keep us warm? How do we use heat in our everyday lives? How did Aboriginal People keep warm? In what everyday activities do we use heat? How do we measure heat? o Discuss in pairs: Have you ever been really cold before? What did you do to warm up? What are the ways that we can keep warm? Have students discuss in groups/ pairs. Share and record answers onto board for the following: stand near something warm, eat something warm, go somewhere warm, go near something warm, warm clothes and move your body. Record ways to keep warm into books. See notebook for examples. Reflection: share ideas with class for the many ways we can keep warm. Extension: start a title page for the new unit. Resources • • https://www.tes.co.uk/teaching-resource/penguin-huddle-6175440 http://www.discovery.com/tv-shows/other-shows/videos/discovery-atlas-snowmonkeys/ Differentiation Students can draw/ list/ write sentences about ways to keep warm. Assessment Work sample in books. Register/Evaluation Lesson 2 : Introduction to…Heat producers WALT: explore the ways that heat can be produced. Take home message: Heat can be produced through friction, combustion and radioactivity. Heat Production 1. Explain to students that we are going to explore the ways that heat can be produced. This lesson we are looking at heat produced through friction, combustion and radioactivity. Explain the WALT: we are exploring the ways that heat can be produced. 2. Reflect on previous lesson by showing students the ways that we can keep warm on page __ of the notebook file. Explain that today we going to be looking at how heat is produced. 3. Ask students if anyone knows what friction is? Ask students to tell the person next to them if their hand is cold, warm or hot. Then ask students to rub the carpet for 10 seconds and see what happens to the temperature of their hand. Ask student volunteers to explain how their hand feels after they rubbed the carpet. Now ask students to rub their hands on their arms. Did the rubbing warm their arms up at all? Did this warm their hands up? 4. Explain that combustion is the process of burning something to make heat. Show the slide about combustion in the notebook file. Explain that wood, gas and coal are the most common materials that are burnt to create heat in our homes. Have student volunteers’ drag and drop the pictures of the items that are flammable and non- flammable into the correct section in the notebook file. Pause when you get to the orange, does anyone think the orange could be flammable? Show the slow motion orange burning clip on youtube. https://www.youtube.com/watch?v=JtazwUWzfWU Remind students that it is the oil in the orange peel that burns and the fruit will not burn. Explain that they need to have parent supervision if they try this at home. 5. Display the picture of radioactivity from the notebook file that show the positive and negative impact of radiant heat from the sun. The images show sun burn and solar panels. Without radiant heat we could not have solar power, but we have to be careful with our skin in the sun. Explain that radiant heat is also useful when we sit near a heater and warm our bodies from the heat. Ask students if anyone has solar panels on their roofs at home? Has anyone ever been sun burnt before? Explain that radioactive energy produced by the sun is capable of burning you and solar panels collect radiation from the sun and turn it into electrical energy that we can use to power our homes. 6. Explain to students that they are going to complete the worksheet detailing the ways that heat can be produced. Show week 2 notebook file with the outline of the worksheet. Have students volunteer their answers to the questions. 7. Students complete their worksheets and paste them in their science books. 8. Extension: Start a title page for the topic HEAT. • Resources • Heat production work sheet - one per student (see week 2 folder) Differentiation Pictures, list examples or write sentences on the heat energy worksheet. Extension: Assessment Students show different types of heat energy onto worksheet. Register/Evaluation Lesson 3: Thermometers Take home message: What is a thermometer? Why do we use them? What does temperature refer to? 1. Show students a thermometer and ask them to make suggestions about its purpose and how it functions. Explain that heat is transferred from a system (or an object) of higher temperature to an object of lower temperature. Inform students that thermometers are used to measure the temperature of something and that temperature is referred to as being either hot or cold. Guided questions may include: What is a thermometer? Why do we use them? What does temperature mean? What are degrees? 2. Show students https://www.youtube.com/watch?v=gvujzYWO5qg about how to read a thermometer. 3. Prepare 2 cups with water at 37c, 3c. Demonstrate how to use a thermometer using the water samples of 37C and 3c for the teacher demonstration. a. Ask students to make a prediction about what they think will happen to the temperature of each cup of water over the half-hour. 4. Conduct the student activity – thermometer practice. Display experiment instructions on board. See notebook file page ___ a. Put students into pairs or small groups so they can compare temperature results. b. Distribute to each group, a plastic cup containing warm water (approx. 37 °C) and a plastic cup containing cold water (approx. 3 °C) and a results template. c. Students take the temperature of each cup of water every 5 minutes for half an hour and record their results. (Students take turns using the thermometer and compare their results to ensure each person is measuring correctly.) d. In between the temperature checks students can answer the questions on the sheet about their predictions. e. Students share their results with the class. 5. Ask students to use their knowledge from the lesson to help explain why the temperature of each cup of water changed. What do they think the temperature of each of the cups will be after 1 hour, 4hours and over night? 6. If spare time: show students the video of how to make your own bottle thermometer at home https://www.youtube.com/watch?v=EbrVwQpgEmc Resources Differentiation Assessment Register/Evaluation Create groups of Results table worksheet. • Notebook file week 3 mixed abilities so • Thermometers (in pairs) HA students can • Cups x 2 per group assist others. • Warm water for 10 cups (37C) Extension: work • Cold water for 10 cups on title page. • Experiment results template – 1 per student (see week 3 folder) • http://scienceweb.asta.edu.au/years-3-4/unit1/lesson-one/yr34-unit-1-lessonone.html for background information Lesson 4: Heat Transmission Take home message: (WALT) Explore the 3 ways that heat can transfer. Heat conduction is the transfer of heat from one warmer object to another colder one. See end of program for background information on heat transfer and examples of student misconceptions. 1) Explain to students that we are going to be exploring the ways that heat can be transferred from one object to another. Do a recap of heat production from lesson 2 so that they are not confused by the two. Have student volunteers offer explanations of the different types of heat production and write onto smart board. Explain that heat production is that way that heat is produced and heat transfer is that the way that heat moves between objects. 2) Explain that today we will introduce these 3 ways that heat can be transmitted: convection, conduction, radiation. • Go to http://www.kidsgeo.com/geography-for-kids/0061-transferring-heat.php and show students the power point slide about heat transfer. Background information on convection (also presented for students in notebook file): Refer students to the images of the kettle and saucepan with water in them informing them that another way heat can be transferred is through convection. Ask students to look at the images of convection heat, eg: water heating in a pot, a kettle boiling, and make suggestions about what they think ‘convection’ means. Define the term ‘convection’ as the transfer of heat throughout liquids and fluids. Explain that convection: is the movement of material, taking the heat from one area to another. The heat has been transferred. Convection is the transfer of heat by motion of liquids. It occurs when, for example, an area of hot water rises to the top of a pot and loses some heat energy, while cooler water sinks to the bottom of the pot and absorbs heat energy from the metal. Another example is warm air in the atmosphere rising and losing heat energy to the surrounding cooler air. Radiation Radiation is heat transfer from indirect contact. Radiant heat can come from the sun, a fire and heaters. You do not need to be able to touch an object/the sun/ fire for radiant heat to warm your body or an object. Conduction Explain that today we are going to focus conduction. Conduction is the transfer of heat from a warmer object to a colder one. Refer back to previous website and notebook file pages and go through the slides about conduction addressing student questions and misconceptions. Conduction can also occur when different states are in contact; it doesn’t have to be only solids. Heat is conducted from a metal saucepan into water, and heat energy is distributed through the water by both conduction and convection. 3) After viewing the slideshow refer to notebook file and ask student volunteers to drag and drop the correct names and pictures in the notebook file to match conduction, convection and radiation. Conduction 4) Ask students to make suggestions about how heat is transferred from a hair straightener to hair. Inform students that heat is transferred through the plates of the hair straightener to our hair by direct contact. Explain that conduction means that heat is transferred from one object to another when they are in direct contact. 5) Pass around the 1 cold glass jar and 1 glass jar with warm water in it. Inform students that when they were touching the cold glass jar they were causing heat to transfer from their hand to the jar. When the feel the warm glass jar their hand was warmed by the jar by the process of conduction. 6) Experiment • Ask students to get into groups of 2 in a circle on the carpet. Nominate 1 student from each group to be the equipment monitor. Ask the equipment monitor to come and collect 1 cup filled with warm water, 1 plastic spoon, 1 metal spoon and 1 paddle pop stick. • Once all students have gotten their equipment back to their group remind them that are to wait for teacher instructions before doing any of their experiment or putting any of the objects in the water. • Direct students to take turns feeling the temperature of the metal and plastic spoons and the paddle pop sticks. Ask students to volunteer their predictions about what will happen to the objects once they are placed in the warm water. What do they predict will absorb the most heat and why? • Conduct the experiment by leaving the objects in the water without being touched for 10-15 minutes. • Students can fill in their predictions and draw their labelled diagram of the experiment while they are waiting. Display an example of a labelled diagram for students to model their diagram from (see notebook file for lesson 4. • Reflection – Ask student volunteers to share their experiment results. Do all students agree that metal was the best conductor? What are our pots and pans made of? What are utensils made of? Ask students to share the reasons why. • Remind students of the 3 ways that heat can be transferred by showing the notebook file slides with images that were dragged and dropped earlier in the lesson. For example, if you have a boiling pot on the stove and put a metal spoon in it, you will burn your hand, because metal is a good conductor (transfer heat easily). If you used a plastic or wooden spoon you would not burn your hand as these materials are good insulators (transfer heat slowly). Resources Differentiation Assessment Register/Evaluation LA groups will Experiment sheet and student • All equipment is 1 between 2. finish their labelled diagrams. o Plastic Cups experiment o Metal spoons results answers in o Paddle pop sticks guided reading o Plastic spoons session on the • Glass jar x 2 for teacher example next day. • Warm water – approx. 42C x 1L Mixed ability • Experiment sheets (see week 4 folder) groups to assist • Notebook file Week 4 LA students. Lesson 5: Heat sources Take home message: (WALT) Objects are heated from burning (chemical), electricity or friction 1) Remind students of last lessons focus on heat transfer and the conduction experiment, also refer to the differences between heat transfer and heat production to ensure that they do not confuse the two strands. Refer to lesson 4 notebook file. Heat transmission: 3 ways that heat can be transmitted: convection, conduction, radiation. Source: http://www.kidsgeo.com/geography-for-kids/0061-transferring-heat.php if they need extra reminders. 2) Introduce heat sources in notebook file: some objects/ materials produce their own heat and some absorb heat from something else. Ask students which objects in the classroom or student homes produce heat? Show students the images of different sources of heat around the home. Ask students to think about familiar sources of heat around the home – heaters, appliances like hair dryers, and fires. Ask students to write a list of the items in their science journals. Have students share the items they identified. Guided questions – are these objects heat producers or do they get their heat from something else? How hot are they: warm, hot, very hot? Background information o Heat producers include: computer, sunlight, candle, fridge motor, heater, matches, people, lighter, stove, oven, o Heated by something else might include: heat packs, hot water bottles, window panes, glass jars on window sills, hot cups or bowls. o Show images of different objects in the classroom and home that produce heat from the list above to get their minds going. o Show a candle - Write candle as the right answer to model the work sheet: was it hot? Why/ why not? What does it need in order to be hot? 3) Fill student responses into table in the notebook file that separates heat producers and items that absorb heat from something else. 4) Students either fill in the heat energy worksheet or create their own tables in their books with the title heat sources. 5) Students share their answers with the class. Resources Differentiation Assessment Work sheet – Heat energy (see lesson 5 folder) 1 per student Notebook file For more images: http://scienceweb.asta.edu.au/years-3-4/unit1/lesson-two/yr34-unit1-lesson-two.html Offer printed copy of heat energy filled in as a template. LA students draw heat sources. Work sheet or table in work books. Register/Evaluation Lesson 6: Insulation Take home message: (WALT) Some materials are insulators that transfer heat slowly. 1) Do a recap of the lesson on heat transfer. Remind students of the conduction experiment where we measured which materials absorbed the most heat. 2) Explain that conduction is the transfer of heat by direct contact and insulators hold in heat and transfer heat slowly. Show students the notebook file pictures of materials that are used as insulators. • For example, if you have a boiling pot on the stove and put a metal spoon in it, you will burn your hand, because metal is a good conductor (transfer heat easily). If you used a plastic or wooden spoon you would not burn your hand as these materials are good insulators (transfer heat slowly). 3) Show interactive resource http://tlf.dlr.det.nsw.edu.au/learningobjects/Content/L7576/object/ to the students and discuss the results of the interact experiment. Why did the ice melt slower when the wool was over the jar? 4) Ask students to explain what examples of insulators they can think of that keep them warm or transfer heat slowly. Guided questions may include: how do you keep warm in the ocean in winter? Why do we use wooden utensils in cooking? Why do we use insulated lunch boxes at school? How do we keep our soup or tea warm? How do we get something hot out of the oven? Insulator ice experiment. • Place a wooden and a plastic chopping board and a frying pan on the table. Ask student volunteers to predict which one will still have solid ice cubes in 10 minutes. Which one will hold the solid ice for the longest and why? • Place the ice on the 3 materials and start the timer in the notebook file. • Send students to their tables to write up their predictions. • After 10 mins get students to draw a picture of the melted ice cubes on each material. • Reflection show the class the ¾ B blog post on the same experiment from last year and compare their results with ours. Were they the same as ours? Ask student volunteers to share their results and explain the reasons for their results. http://34bthps.edublogs.org/2015/10/22/science-insulators-and-conductors/ Resources For background information and addition images http://scienceweb.asta.edu.au/years-3-4/unit1/lesson-three/yr34-unit1-lesson-three.html Interactive example http://tlf.dlr.det.nsw.edu.au/learningobjects/Content/L7576/object/ http://primaryleap.co.uk/primaryresources/1860/Year+4/Science/Unit+4c+Keeping+warm/Thermometer/#.V1-vjaJBF-8 Experiment materials • Ice/ frozen ice block • Plastic chopping board, metal pan, wooden chopping board • Timer – use smart board • Experiment work sheet (1 per student- see lesson 6 folder) Extra resources/ experiment alternatives Melting ice cube experiment https://www.youtube.com/watch?v=ZoyVTEHhpxw insulator vs conduction https://www.youtube.com/watch?v=pyfM_fKSICE Differentiation Assessment Register/Evaluation Lesson 7: Keeping Warm Take home message: (WALT) Heat can be retained using insulators 1. Remind students that heat travels quickly through conductors, like metal, but insulators like plastic and wood do not let heat travel through them easily. 2. Explain to students that we are going to explore how heat can be retained using different materials to see which materials hold in the most heat. Show students some pictures of cold places and appropriate clothing that is warm in the notebook file. Eg down clothing in the snow and warm sleeping bags that are appropriate for minus temperatures. Show students warm clothing items and the picture of the dog under the doona in the notebook file and explain how these items acted as insulators. Guided Questions: How do we keep warm in cold places? Why do we want light and warm clothes while we are hiking? Which clothes have you worn to stay warm? What is your bedding made of at home? 3. Show students http://www.bbc.co.uk/schools/scienceclips/ages/8_9/keeping_warm_fs.shtml Explain that some materials are good thermal conductors, easily letting heat pass through them, while others are good thermal insulators, not easily letting heat pass through them. Conduct the interactive experiment link from above and watch how the temperature changes. 4. Ask students to record their results on the table and make their own conclusions, some materials help keep things warm while others allow heat to pass through more quickly. Find out if metal, cardboard and polystyrene are good at thermal insulation or have good thermal conductivity by conducting the heat transfer activity. 5. Fill in the final table on the above website and discuss the results. 6. Students fill in the table on their own worksheet and fill in the questions: which materials retained the most and least amounts of heat? Resources Down jacket, gloves – or any warm clothing to show Table to record results (1 per student) see notebook folder lesson 7 http://www.bbc.co.uk/bitesize/ks2/science/materials/heat/read/1/ Differentiation Assessment Students work in Worksheet table of results. mixed ability pairs to fill out the worksheet. Register/Evaluation Lesson 8: Changing States Take home message: (WALT) Removing and adding heat will change states of matter Changing States 1) Ask student volunteers to explain what they know about the 3 states of matter: Give a brief overview of the three states of matter: solid, liquid, gas using water as an example. Demonstrate the 3 states of matter using the pictures in the notebook file and http://www.bbc.co.uk/bitesize/ks2/science/materials/changing_states/read/1/ . Guided questions – are there any other materials that change states that they can think of? Why do you think that these materials are changing states? Is heat playing a role? Is freezing playing a role? Examples may include: chocolate, jelly, ect. 2) ) Explain the role that heat plays in changing the state of substances – gases are in their gas form because of heat, if we were to remove heat, these substances would return to their liquid form. Please note that gas will only be mentioned in this unit and will not be covered in detail.) Explain how water can change into all 3 states- water/ice/steam, but chocolate and butter can be liquid or solid. Changing states experiment – Outdoor if possible 3) Warm the ice magic so that it becomes liquid. Pass the bottle around or shake it so that students know that it is liquid. • Place 3 pieces of ice into a bowl. Pour some Ice Magic onto the ice and explain that it is a liquid at first, but quickly becomes a solid after the removal of heat. 5) Chocolate experiment: Explain that we will be investigating chocolate changing from solid to liquid. Hand 1 piece of chocolate to each student and tell them to try different techniques to see how quickly they can melt the chocolate. They can use friction from moving their hands, insulation from keeping their hands closed or radiant heat from the sun. Allow students to eat the chocolate after it has begun to melt. 6) If extra time: Ask student volunteers to hold ice in their hands and see what happens to their hand (gets colder) and also to the ice (gets warmer and melts). Ask students to explain why the ice is melting and changing from a solid (from the addition of heat.) Reflection 7) Show students this link to demonstrate how adding and removing heat is important for survival. Ask student volunteers to make selections for changing states in the snow to survive. http://www.bbc.co.uk/bitesize/secondlevel/sciences/planet_earth/changing_state/play/ Resources • • • • • Ice magic Ice Warm water/ microwave to melt the ice magic (for teacher use only) Chocolate block bowl If unable to do an experiment follow this link to interactive examples http://www.bbc.co.uk/schools/scienceclips/ages/9_10/changing_state.shtml or http://www.bbc.co.uk/bitesize/ks2/science/materials/solids_liquids/play/popup.shtml - Differentiation Have ice and ice magic for students to use if they are allergic to dairy/ chocolate. Assessment Register/Evaluation Lesson 9: Assessment Take home message: Review the content from heat unit 1) Ask students to tell a partner the main concepts that they remember from the unit on heat. 2) Go through an overview of the unit using notebook files and remind students of the experiments that we conducted and the concepts that we were testing along with experiment results. 3) Go back to the KWL chart from lesson 1 by asking student volunteers to share the information into the L (learnt) section of the chart. 4) Hand out the science assessment 5) Early finishers record their highlights of the heat unit. Resources Assessment sheet 1 per student Previous notebook files Differentiation Read questions to students in need of reading assistance. Assessment Science unit assessment Register/Evaluation Teacher background information: Primary Connections – Heating Up (Heat Transfer) Introduction to heat • Heat is a form of energy created by the movement of molecules in an object. All matter is made up of atoms and molecules (groupings of atoms). The atoms and molecules of a material are always moving. Even objects which are very cold have some heat energy because their atoms and molecules are still moving. • When molecules get more energy in them than they had before, they move faster, and we call that heat. Things are hot if their molecules are moving quickly and cold if their molecules are moving more slowly. Temperature is a way of measuring how fast the molecules are moving. • Heat itself isn’t a ‘thing’ but rather a process of energy transfer. For example, when you hold a cup of hot coffee, heat flows from the cup to your hand—the hot thing warms up a cooler thing by the transfer of heat or heat energy. As the cup of coffee is hotter than your hand, the molecules in your hand move faster as heat energy flows from the cup to your hand. Over time, the molecules of the hotter object slow down and the molecules of the colder object speed up until eventually the two objects are the same temperature. • If you leave your cup of coffee on your desk and come back to it later, the heat will have flowed from the cup to the room until the coffee is the same temperature as the room (called equilibrium). Storing and producing heat Heat has its origins in other forms of energy: • The Sun changes nuclear energy into light and heat energy. • A fire and living cells can change chemical energy into heat energy. • Some electrical devices can change electrical energy into heat energy. • Kinetic (motion) energy can be changed into heat energy through friction. • • These are all examples of primary sources of heat. We might produce heat as a side product of any work we might do. Secondary sources of heat do not produce heat themselves but are previously heated by a primary heat source. If then moved to a cold environment they exchange heat with objects around them until all materials reach the same temperature. • • Students’ misconceptions to be aware of Students might think that the terms ‘hot’ and ‘cold’ are absolutes and opposites. However, ‘hot’ can be translated as ‘has a higher temperature than me’ and ‘cold’ as ‘has a lower temperature than me’. We intuitively understand the world in terms of what is hot or cold to us, but this would be very different if, for example, we had an internal body temperature of 120°C. Students might think that ‘cold’ moves from one material to another. Statements such as ‘Don’t let the cold in!’ imply this. Heat energy always transfers from the hotter object to the colder one. • Teacher background information: Primary Connections – Melting Moments (Changing states) Matter All matter is made up of very small particles called atoms. These atoms can join with other atoms to form molecules. Every type of material contains specific types of atoms or molecules resulting in different materials having different properties. For example, gold is made up of gold atoms only. Water is made up of water molecules, a combination of hydrogen and oxygen atoms. The way the atoms or molecules are arranged in a material will affect its state of matter. States of matter A material might be found in different states. The most familiar states are solid, liquid or gas. Other states of matter are now recognised, for example, plasma and liquid crystal but these will not be dealt with in this unit. The amount of energy the atoms or molecules of a material possesses determines its state of matter, for example, the molecules in solid chocolate have less energy than those in melted chocolate. • Solids have atoms or molecules that are held together with rigid bonds. The atoms vibrate in place but they do not change position. This means that a solid holds its shape and does not flow, nor can it be significantly compressed. • Liquids have atoms or molecules that are held together with weaker bonds. They stay close together and so occupy a constant volume of space. Thus a liquid can only be compressed a little bit, if at all. However the bonds are loose enough to let atoms or molecules slide past each other. Due to the force of gravity a liquid flows and takes the shape of the container into which it is poured. Gases are not considered in this unit. They are not included in the ACARA Year 3 Science Understanding description. For students of this age the properties of gases are considered conceptually difficult to understand. Changing states Materials exist as particular states of matter at particular temperature and pressure conditions. These are specific to the material. For example, at room temperature and normal air pressure water exists as a liquid and iron exists as a solid. Increasing the temperature eventually changes solids to liquids (the iron will melt) and liquids to gases (the water will become a gas). The temperature at which a liquid changes to a gas is called the boiling point; the temperature at which a liquid changes to a solid is called the freezing point. Differences in pressure change the boiling and freezing points of materials. The boiling point of water at atmospheric pressure of 1 bar (sea level) is 100°C. However at lower pressures, for example, on a mountain top, the boiling point of water decreases (1°C for every 285m in elevation). Early explorers used to judge their altitude by measuring the boiling point of water. Water boils at 69°C on the top of Mt Everest. Viscosity is a measure of the ability of a liquid to flow. Some liquids (more viscous) such as oil or honey do not flow as easily as other liquids (less viscous) such as water or alcohol. Students’ conceptions Students are strongly influenced by everyday language, and can use the term ‘solid’ to denote something as hard or large. They tend to use it as an adjective rather than to describe a set of substances. They might have difficulty understanding that the same material can be solid or liquid depending on the temperature. Some students identify all liquids with water, and the most common liquids identified by students are water-based, including dishwashing liquid, milk, seawater, cordial and lemonade. More viscous liquids such as oil, paraffin and honey are less commonly identified as liquid. Students might also assume that all liquids contain water and that melting involves a substance turning to water. Online resources- Changing States • • BBC Bitesize: http://www.bbc.co.uk/bitesize/ks2/science/materials/changing_states/read/1/ Game: http://www.bbc.co.uk/schools/scienceclips/ages/9_10/changing_state.shtml • http://www.chem4kids.com/files/matter_changes.html • http://www.skwirk.com/p-c_s-4_u-302_t-738_c-2766/SA/3/From-solid-to-liquid/Changing-states/Material-world/Science/ • http://www.australiancurriculumlessons.com.au/2014/04/26/melting-ice-cubes-science-lesson-plan-learning-solids-liquids-gases/ • http://interactivesites.weebly.com/matter-chemical--physical.html • • https://www.schooltube.com/video/ea7dae4437c240958f92/Bill%20Nye%20The%20Science%20Guy%20Phases%20of%20Matter • • • • • • • • • Heat transfer https://www.tes.com/teaching-resource/heat-transfer-11211436 http://elonparktech.weebly.com/3rd-grade.html http://elonparktech.weebly.com/3rd-grade.html Bill Nye the Science guy video http://scienceweb.asta.edu.au/verve/_resources/asta_3-1-1_bi_heat_yr3_v1-2.pdf Lesson plans Convection https://www.youtube.com/watch?v=f1eAOygDP5s https://www.youtube.com/watch?v=DmnQD3eEkNk http://www.slideshare.net/firstgradewalks/heat-light-and-sound