![]() ![]() Pose the following question to the students and ask them to discuss their initial ideas. Challenging students to think about where and how physical and chemical changes happen begins to engage their understanding about changes in substances. The chemical change happens where some of the wax vapor burns since it produces carbon soot, water vapor, and carbon dioxide. Burning a candle produces both a physical change: the wax melting and then hardening again and also a chemical change. If necessary, review what happens in a physical change and chemical change. Ask the students to consider what type of changes happen with the burning of a candle and explain why.15–18: When fuel is carried to the part of the candle where burning happens, what is that action called? What are some of the key parts of the candle? What is happening when it is lit? How did the shape help the candle burn? 11–12: Look closely at the diagram of the candle when it is lit. ![]() 7–8: How did Michael Faraday describe the candle that he was using in his demonstration? What were the candles made from? Now that students have been provided some context, read the story Burn: Michael Faraday’s Candle to the students and discuss the following points: This is a retelling of his lecture for students in the form of a picture book. During that time, lectures or presentations were given at the holidays and his lecture encouraged kids to really observe a candle and determine how it burned. Specifically, tell students that Michael Faraday was a scientist who lived in England in the mid1800s. Provide some context for the students about the story that they are going to hear. Construct an argument with evidence that some changes caused by heating or cooling can be reversed and some cannot. The materials, lessons, and activities outlined in the article are just one step toward reaching the performance expectation listed below.Ģ-PS1-4.Students observe what happens during different changes and determine what type of change it is. Students engage in demonstrations that represent physical or chemical changes identify if heat is involved in making the change and determine if the change can be undone (reversed) or not. Sometimes these changes are reversible, and sometimes they are not. Heating or cooling a substance may cause changes that can be observed. Students discuss what happened in each station and describe why it is a physical or chemical change. Explain how the eggs were changed by adding heat to them while they were in the pan. 20: In the story, the young girl cooks the eggs and makes scrambled eggs. 15: If the butter warmed up when taken out of the fridge, what change happened to it (physical or chemical)? What would happen if you were to put the warm butter back into the fridge? Why is this a physical change? What happens to the muffin batter as it is heated? Can this change be undone or reversed? Each of these ingredients were mixed together. 12: We used different ingredients in the muffin mix, such as eggs, flour, baking soda, and blueberries. 7: What happened when too much heat was used to toast the bread? What observations can you make about the change from the bread to the toast? Could they change the toast back to bread? 4: When the children decide to cook food for their parents, they state that they will need heat to do so. Tell the students that they are going to discuss parts of the story and they should think about where heat was used and what kind of change happened. Return to the following pages in Do You Really Want to Burn Your Toast? and connect the story to the concepts related to heat and change. The ideas are physical change, chemical change, reversible, irreversible. Help students understand each of these ideas by discussing the ideas and adding the proper terminology to what is happening in each demonstration. ![]()
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