Melting and Freezing

Purpose of this lesson is to explore what happens to the amount of different substances as they change from a solid to a liquid or a liquid to solid. This lesson is the third in a three-part series that addresses a concept that is central to the understanding of the water cycle—that water is able to take many forms but is still water. In the guided inquiry explorations outlined in this complete lesson plan, students observe changes in water, margarine, and chocolate as the temperature is increased.  They are encouraged to compare what happens to each substance.  Questions which the teacher can use as the experience takes place, as well as afterwards, are included.  There is also a suggestion for assessment. 

Weblink address (URL): 
Melting and Freezing

Standards & Objectives

Learning objectives: 

Purpose:

To explore what happens to the amount of different substances as they change from a solid to a liquid or a liquid to solid.

Essential and guiding questions: 

Ask students:

  • What do you see?
  • What is happening to the ice?
  • Why is this happening to the ice?
  • What do you think is happening to the amount of ice?
  • What happened to the amount?
  • Does the ice look the same as it did in the beginning? How is it different?
  • Does the amount of water change when it changes from a solid (ice) to a liquid?
  • Does the amount of water change when it changes from a liquid to a solid?
  • Imagine that a younger friend has just told you that the amount of ice is gone because she saw it melt. How would you explain her mistake to her?
  • How would you explain what you observed to someone who did not perform this experiment?
  • What happened to the amount of chocolate chips as they melted?
  • What happened to the amount of chocolate chips as they changed to a solid?
  • Did you expect this? Why or why not?
  • If you took a cake and cut it into pieces, would the amount of the cut cake be more, less, or the same as the uncut cake? Draw a picture of both cakes that explains your answer. Be prepared to explain your drawing.
  • What happened to the amount of margarine as it changed from a solid to a liquid?
  • What happened to the amount of margarine as it changed from a liquid to a solid?
  • At dinner you see a bowl of vegetables on the table with a pat of margarine on the top. As the margarine melts into the vegetables, what happens to the amount?

Lesson Variations

Blooms taxonomy level: 
Understanding
Extension suggestions: 

Extensions:

Read the story, White Snow Bright Snow by Alvin Tresselt to the class.

 

Ask students:

  • What is snow?
  • What happened to the snow as the temperature increased?
  • Did the amount change as the snow melted and turned to a liquid?
  • Why did the snowman appear to get smaller? What was really happening to him? Did the amount of the snowman really change? Why or why not?

 

Helpful Hints

Materials:

  • Ziploc baggies
  • water/ice
  • chocolate chips
  • margarine
  • paper towels
  • scale/balance

References

Contributors: 
Kay Jordan
Originator: 
Ayers Institute for Learning & Innovation