# Fast and Easy Science Fair Projects: Walls Don't Move

Updated on December 30, 2019

## Newton's 3rd: Action and Reaction

Purpose: Understanding the Physics concept of work through force and distance.

Overview: Newton's third law of Motion explains that if one body exerts a force on a second body (action), the second body exerts and equal force in the opposite direction (reaction), back to the first body. In other words: For every action there is an equal and opposite reaction. Imagine yourself and a friend floating in a swimming pool, in two liner tubes touching each other. If you push your friend's tube away, the force will push back and yours will move, too. Astronauts in orbiting spacecraft push against walls in order to float backward. Work, in Physics, is defined as: work = force x distance. Since anything is multiplied by zero is zero, if either force or distance is zero, then work equals zero.

Hypothesis: According to the Physics definition of work, it is possible that no work is done, no matter how much effort is used.

You need:

• Roller or in-line skates
• Flat surface and wall

Procedure: Wearing shoes that won't slip, stand facing a wall and push on it as hard as you can. The wall doesn't move, and you don't move. Force x distance = zero. No work was done (no distance, no work). Even if you pushed long enough to work up a sweat and you are out of breath from trying, technically no work was done because nothing moved. Although effort or force was applied, no work was accomplished!

Now, put on roller or in-line skates. Face the wall and push against it. Again, the wall doesn't move, but a force equal and opposite to yours pushes back, causing you to roll away from the wall. The wheels reduced friction, you rolled...and work was done!

Results and Conclusion: Write down the results of your experiment. Come to a conclusion as to whether or not your hypothesis was correct.

Something more: Measure the distance you traveled from the wall by pushing on it. If you push harder (apply more force), does the distance increase? Is the distance you travel in relation to the force you apply?

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