Summary

In this activity, students will investigate methods for purifying water as they consider a survival based situation that requires clean drinking water. Students will investigate processes such as boiling and distillation, as well as review the phase changes within the water cycle.

Grade Level

Middle School

Objectives

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

• Describe the distillation process, including specific reference to evaporation and condensation.
• Explain the changes in states of matter during distillation.
• Understand that water is an essential need for the human body.
• Explain how a solar heat source can cause the temperature of water to rise and cause a physical change.
• Create a clean water supply by the process of distillation.

Chemistry Topics

This activity supports students’ understanding of

• Distillation
• Physical Change
• Separating Mixtures
• States of Matter
• Phase Changes

Time

Teacher Preparation: 10 minutes

Lesson: 1 hour

Materials

• Student Activity Sheet
• Computer/Tablet with internet access

Safety

• No specific safety precautions need to be observed for this activity.

Teacher Notes

• Begin this activity by introducing the scenario presented on the student handout. This could be read aloud, or students can read it independently from the handout. Then lead the class in a discussion using the initial 3 questions on the student handout. Allow students to answer them on their own first, and then have students share their responses and record them on a chart, board, etc. so they are visible to all of the students.
• Next, introduce the concept of potable water (pronounced poh-tuh-bul), or drinkable water. It will soon become the family’s most important need. In this activity, science will be used to discover how to make sure that the family will have a potable, or clean, water source to survive while awaiting rescue.
• The following concepts will be discussed: water purification, the water cycle, distillation, phase changes, and the states of matter.
• For the “Research” section of the student handout, the website/resource included is a link to the Outdoor Life website’s post about survival skills. The title and link for the post are: Survival Skills: 10 Ways to Purify Water.
• You may wish to have students use an alternative resource for their resource. You can instruct students how to proceed based on their ability level. Students may be given time to do some independent research, or brainstorm together about the water purification techniques. Below are some examples of discussions that can be used with students. (Remind the students that they have to have a constant water supply for all water purification):
  • Boiling water: What is needed in order to boil water in this situation? Responses: this requires a constant water supply, fire, pot or other item to hold the water (the item must be able to withstand heat).
  • Water purification tablets: Do you carry water purification tablets with you all of the time? Were you expecting to need those things on this trip (refer them back to the beginning scenario)?
  • Water filtration system: In the original scenario, did it state that you and your family had access to a water filter in your vehicle? Is this a reasonable water filtration source for you and your family?
  • Solar still: What do you think is a solar still? What do you think is needed to create a solar still? Define “still”.
  • Distillation: Is heat required? Have you seen this before? Is an equipment needed?
• Lead the students to a discussion of the water cycle and discuss evaporation and condensation. Use this as segue into the steps to the distillation process, and the change in states of matter.

Optional:

• This activity can be followed with an optional demonstration of Distillation; this video is a good quick example.
• Solar water distillation could also be demonstrated or shown via video.
• AACT has a simple distillation lab that could be used with students.