Friction

Target Subject: Physical Science

Authors

Michele Engelbrecht and Kate Fraser

Purpose

To identify increases in friction

Background Information

Friction is a force that can be felt. Commonly used activities to demonstrate and experience friction in a regular class room work well for students with visual impairments. Carrying out hands on activities enable the student to fell the ease with which the rock slides along the bare table top, then to compare that feeling to pulling the rock over the gritty sandpaper.

Preparation

Adapt a traditional spring scale by applying puff paint to the measurement lines.

Materials

Large piece of sand paper
Spring scale  
Smooth rock
String
Tape
Data Table

Procedure

1. Place the smooth rock on a tabletop.
2. Tie a string around the center of the rock.
3. Attach the spring scale hook to the top part of the string.
4. Pull the rock across the table with a constant velocity (constant speed and direction). 
5. Record the force in Newtons in your data table.
6. Now tape the sandpaper securely to the tabletop.
7. Pull the rock across the sandpapered surface with a constant velocity (constant speed and direction).
8. Record the force in Newtons in your data table.
9. Compare the data and notice which activity required more Newtons of force.   

Resources

Concepts and Challenges: Physical Science, Fourth Edition. Parsippany, NJ: Globe Fearon Inc., Pearson Learning Group, 2003 and 2009 pages 254 to 255.