Tug-Push-Twist-O'War
Materials Lab Hands-On Activity Handout
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How tough is this stuff?
Have you ever seen a skyscraper made of paper? Probably not, because paper is not a strong enough material to withstand the forces acting on a skyscraper. Some materials withstand tension well but not compression, while others are just the opposite. Hold a miniature Tug-Push-Twist-O'War to find out which materials can best withstand these different forces.

What You Need
20-30 minutes
Three samples of each of several different materials, such as yarn, popsicle sticks, pipe cleaners, clay, sponges, rubber erasers, rubber bands, paper-towel tubes, pencils, paper, cardboard, aluminum foil, drinking straws, or cloth.

Make a Prediction
Before you test the materials, predict which ones will be strongest in tension, which in compression, and which in torsion.

Try It Out

1. First make a table like the one below to record your results. You'll rate each material for each type of stress:
1. Very weak! It crumples or breaks with hardly any force.
2. Only fair -- it can't withstand much force.
3. Pretty good -- it takes a lot of force to break it.
4. Super strong! We couldn't break it.
2. Tug: To test the material in tension, pull on it from both ends. Record your rating and any observations in the table.
3. Push: To test the material in compression, push it together from both ends. Record your rating and any observations.
4. Twist: To test the material in torsion, twist the two ends in different directions. Record your rating and any observations.
5. Repeat Steps 2-4 for each material.

Explain It
Which materials were strongest in each type of stress? Did any of these results surprise you? Why or why not? Which materials were strongest across all three tests? How would you describe those materials?

Build on It
Does the shape of a sample of material affect how well it performs in the Tug-Push-Twist-O'War? Choose a material and design a test to answer this question.