Summary

In this lab, students will investigate what factors influence the change in state of matter from a solid to a liquid. They will make a hypothesis and design and participate in an experiment to see how different heating methods affect how fast an ice cube melts.

Grade Level

Elementary School

NGSS Alignment

This lab will help prepare your students to meet the performance expectations in the following standards:

• 3-5-ETS1-2: Generate and compare multiple possible solutions to a problem based on how well each is likely to meet the criteria and constraints of the problem.
• Scientific and Engineering Practices:
  • Planning and Carrying Out Investigations

Objectives

By the end of this lab, students should be able to:

• Describe factors that affect how fast ice changes to liquid water.
• Construct a hypothesis statement that relates to the experiment.
• Understand that adding heat can impact the state of matter of a substance.

Chemistry Topics

• States of Matter
• Phase Changes
• Physical Properties

Time

Teacher Preparation: 10 minutes
Lesson: 55 minutes

Materials

Per group

• 1 or 2 ice cubes, each in a zipped baggie
• Student handout
• Timer (one for the whole class)

Safety

• Always wear safety goggles when handling chemicals in the lab.
• Students should wash their hands thoroughly before leaving the lab.
• When students complete the lab, instruct them how to clean up their materials and dispose of any chemicals.
• Make sure the students’ hands are not wet when handling the ice cubes. The ice can stick to their skin, and it can be painful removing it.

Teacher Notes

• Remind students that the process of melting ice will take time, and that they are trying to find out what methods cause the ice to melt the fastest.
• Emphasize that heat is always necessary to melt but depending on the conditions there are different amounts of heat necessary.
• The ideas in this lesson could be connected to weather and climate events as well, tying in the Arctic and icebergs. See resource list at the end of the teacher notes for more ideas.

Discussion:

• Start the lesson by asking students these discussion questions:
  • Has anyone ever eaten ice cream on a hot summer day? What happens to it if it is not eaten quickly?
  • Have you ever left a glass of ice water out on the table? What happened to the ice?
  • Have you ever noticed what happens to frozen objects as they heat up?
  • What happens to the amount of a substance if it is changed from a solid to a liquid? (It may not look the same, but the amount of substance does not change.)
  • Discuss what can be done to an ice cube to make it a liquid.
• Explain that they will conduct an experiment to melt ice cubes to see what makes them melt fastest. As a class, have students brainstorm different ways they can melt an ice cube and list them on the board. Remind students that heat can change the state of matter and adding more heat might make the state of matter change faster.
  • Ideas for melting the ice might include:
    • Placing it in a sunny spot
    • Using an electric heat source (ex: heat lamp, space heater, heating pad, hair dryer, etc.)
    • Warming it with their hands (winter/cotton gloves should be worn)
    • Breathing on it
    • Wrapping it in a towel
    • Putting salt on it (like salting roads in the winter)
    • Crushing it into more than one piece

Prediction:

• As a class, have students predict the answers to the following questions based on their suggestions:
  • Which method do you think will melt the ice cube the quickest?
  • How long do you think it will take?
  • Introduce the scientific vocabulary word hypothesis to the students.
• Distribute the student handout and assign each group one or two of the above methods (depending upon age level of students). Students should fill in the description of each of the melting methods they will test as well as their hypothesis including time predictions for each.
  • Encourage students to be detailed in their descriptions of their methods – when scientists write about their experiments, they need to provide clear descriptions of what they did so other scientists could repeat the experiment the same way.

Experiment:

• When all groups are ready, draw their attention to the timer (project the timer on a screen in the classroom if possible). Explain to students that everyone must start at the exact same time. Students may enjoy making this a competition among groups within the class!
• When each group has completely melted their ice cube, they will note how long it took to melt on their activity sheet.

Conclusion:

• Discuss and share results.
• Compare the estimated times and if the predictions were close.
• Students should share times and methods with the class, discuss which methods were most successful and what students might change/improve.
• Discuss what factors would turn the water back into an ice cube.

Extension:

• Review the importance of controlling variables in an experiment. The size and shape of the ice cubes should be the same, for example.
• Experiment with another type of solid – try melting chocolate chips (see “Chocolate Changes” lesson plan below) or butter. The kids love it.
• Have students weigh the baggies with ice before and after melting to illustrate the law of conservation of matter.
• You can also have students use the National Center for Education Statistics website to graph the class results.

Related resources:

• Related classroom resources from the AACT Library that may be used to further teach this topic:
  • Lesson Plan: Introducing States of Matter
  • Lesson Plan: Investigating Water’s States of Matter
  • Lesson Plan: Let’s Get Physical About Water
  • Lab: The Insulation Investigation
  • Lesson Plan: Salting Roads in Winter
  • Lesson Plan: Pothole Science
  • Lesson Plan: Chocolate Changes