Viscosity Race

The Equity Project (TEP)

Summer Research Program for Science Teachers

August 2012

Subject: General Science

Unit: Earth Science OR Properties of Matter

Time required: One 50 minute class period

Purpose:  Within the earth science unit, students are exposed to how magma and lava flow through the concept of viscosity.

Objectives:

SWBAT

·         observe the properties of two liquids

·         compare the viscosities of both liquids

·         explain the difference between a high and low viscosity liquid

Materials:

·         aluminum tray

·         “Race track” – homemade- card stock paper inside of a clear sheet protector. The cardstock has drawn on it “Starting line” and “Finish Line”

(the purpose of the sheet protector is to reduce friction and allow the soap to travel faster)

·         Eyedroppers

·         Dish soap

·         Laundry detergent

Procedure:

Before the activity begins, discuss viscosity with students. Explain that viscosity is a liquids resistance to flow. Give examples of one liquid with a high viscosity (cold honey) and a liquid with a low viscosity (water). Have the students brainstorm 2 more liquids that they know about in their daily lives that have a high and 2 that have a low viscosity. What are the visual observations that you can make about a liquid that has a high viscosity? What about a low viscosity? How might you test the viscosity of a liquid?  Invite a discussion before class so students can have an idea in testing this concept before you discuss the procedure.

Explain that in today’s lab, we will be conducting a viscosity race!

1.      Gather all materials

2.      Place the racetrack inside of the aluminum tray.

3.      With the racetrack flat, drop 10 drops of dish soap onto the starting line, and 10 drops of detergent next to it on the starting line.

4.      Hold the race track at a 90 degree angle to the aluminum tray, and using the timer, time how quickly (in seconds) both liquids reach the finish line.

6.      Repeat steps 3 thru 5 twice more- students will have 3 races total.

Homework: Bring in one liquid (with the exception of water) that you think would have the lowest viscosity and win a class wide viscosity race.

Extension Questions:

1.      How do you think temperature might affect the viscosity of a liquid?

2.      If you could do this lab again, what two liquids might you test?

3.      What is one way you could slow the viscosity of a liquid?

4.      How does this lab relate to earth science?

New York Science Standards:

Physical Science 3.1 properties of solids, liquids, and gases