Summary

In this lab, students will be given a test tube with four substances with unknown identities to the students. They will mix the substances in the test tube and recreate the original four layers through chemical and physical means.

Grade Level

High school

Objectives

By the end of this lesson, students will

• collect quantitative and qualitative data and use chemical and physical properties to separate a mixture.

Chemistry Topics

This lesson supports students’ understanding of

• Chemical change
• Physical change
• Separating mixtures

Time

Teacher Preparation: 30 minutes

Lesson: 2 class periods

Materials

For each group:

• Test tube with four (unknown) layers
• Empty test tube
• Hot plate
• Water
• Stirring rod
• Beaker
• Filter
• Magnet
• Other materials as students request

Safety

• Always wear safety goggles when working 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.
• Students should exercise caution when using a heat source. Hot plates should be turned off and unplugged as soon as they are no longer needed.

Teacher Notes

• The following substances are possible layers, but other substances can be substituted: sodium chloride, iron filings, sand, and wood shavings.
• I do not tell the students what the substances are.
• This is a relatively simple lab to prepare. The lab is inquiry and students can be given very little prompt to successfully separate the mixture and return it to its original state within the test tube.