Safety Note: Be aware that Hershey’s Kisses are processed in a plant that may use nuts. Some students may have peanut allergies and should not handle or be exposed to these items.
Day 1
Engage: Tell students, “In today’s lesson, you will be using the information you learned in earlier lessons to help you understand how matter can change forms, and then change back to its original form but a different shape. This information might help you understand some events in your daily lives.” Remind them, “You will be thinking like a scientist as you continue to investigate the properties of matter and as you ask the question, ‘What happens when we apply a stronger heat source to the Hershey’s Kiss and then take the heat away quickly?’”
Have the students make predictions in their journal.
Using the KWL Chart from Lessons 1 and 2 (S-K2-8_ KWL Chart.doc) to review and using the following discussion questions, ask students:
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“What are senses? What do they do for us?” (Possible responses: They help us understand and describe our world. We see, hear, feel, smell, and taste–only when we know it’s safe–with our senses.)
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“What do you now know about the physical properties of matter?” (Possible responses: They help us describe items. The physical properties are color, size, shape, hardness, flexibility, weight, and texture)
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“From what we know about our senses and the physical properties of matter, how can we tell what will happen when we add heat or cold to an object?” (Possible responses: The heat made the object change.) “What do we call this?” (changing states of matter).
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“What states did the Hershey’s Kiss change from and to?” (from a solid to a liquid).
The heat made the object change. “What do we call this?” (changing states of matter) Review by reflecting back on what happened when they put the crayons in the muffin tin.
Place the Hershey’s Kiss in one of the muffin tin compartments. Ask: “Why can’t the Kiss take the shape of the tin?” (Possible responses: The Hershey’s Kiss needs heat. The Kiss needs to melt first. The Kiss needs heat to make it melt and match the form of the tin.) “Now, let’s try that to see if our thinking is on the right track.”
Have students make their own mold using heavy-duty aluminum foil. Give each student a 3” x 3” sheet and ask him/her to make an interesting shape with the foil.
Model the process in order to make the mold with the students.
Ask students to unwrap two Hershey’s Kisses and place them in their mold. Label each mold with the student’s name.
Day 2
Add a couple of extra molds for classroom demonstration. Put all the molds with the unwrapped Hershey’s Kiss on a cookie tray and place the tray in or on a heat source. While the molds are heating, discuss what changes might occur to the Kisses. (The time to melt the Kisses will vary depending on the heat source used.)
After the Hershey’s Kisses have melted but not cooled, demonstrate with one of the extra molds that the Kiss has changed to a different state of matter and taken on the shape of the mold. But it doesn’t stay in that shape. Discuss with students why this happened and what you could do now to “force” the Kiss to keep the shape of the mold. Guide students in realizing that placing the molds in the freezer will cause the Kiss to stay in the shape of the mold.
Place the melted Hershey’s Kiss molds in the freezer (approximately 10 minutes). Ask students about other liquid items they have put in the freezer and what resulted. After the allotted time, take the Hershey Kiss molds out of the freezer and give the molds back to the individual students. Have students predict what they think will have occurred. Have students slowly pull the aluminum foil away from the Hershey’s Kiss and discuss their observations.
Hand out the Science Journal activity sheets (S-K2-8-3_Science Journal.doc). Allow students time to illustrate their observations on their Science Journal sheets.
Ask, “How has the Hershey’s Kiss changed during this process?”(Possible responses: It changed. It changed to a different state of matter. It is now a solid again. It is now hard again.) “What changed about the Hershey’s Kiss? What stayed the same? Is the new form still a Hershey’s Kiss? Why or why not?” (Note: There is no right or wrong answer. It is the same substance; just the shape has changed. This is a great time to discuss differences of opinion and respecting another person’s idea. Help students understand the concept “agree to disagree.”)
After students have recorded their observations for this lesson in their Science Journal, ask them:
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“We have seen how changes can occur to the Hershey’s Kiss. Can you think of other things we can change?” (Possible suggestions: water to ice cubes, dough to cookies, lemons to lemonade, melted butter to a pat of butter)
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“How did the object change? What caused the changes? Can the changed object change back? If not, why not?”
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“What is a term for what is all around us?” (Students should respond with, “matter.”) Matter is everywhere; it has mass and takes up space.
Extension:
