# Fast and Easy Science Fair Projects: Crash!

Updated on December 30, 2019
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## The relationship between mass and force

Purpose: It often happens that objects are at rest, that is, not moving, are hit by moving objects and forced to move. What happens when the objects struck have different masses?

Overview: Sir Issac Newton did experiments to find the mathematical relationship between the mass of an object and how fast it moves when a given force strikes it. Mass is how much "stuff" an object is made up of. Newton found that the larger the mass of an object, the smaller will be its movement when a given force is applied.

Imagine a soccer ball filled with air and another one that is filled with sand. If you kicked each soccer ball with the same amount of force, the ball with more mass (filled with sand) would not move as far as the one with less mass (filled with air). You might hurt your foot on the ball with more mass, too!

Hypothesis: A soccer ball will move farther than a bowling ball when the same force is applied to each.

You need:

• Soccer ball
• Bowling ball
• Golf ball
• Several thick hardback books
• 2 wooden boards, 2-by-4 inch by 8 feet (240 cm) long
• Hammer
• 6 long nails
• Ruler

Procedure: Let's strike a bowling ball (in place of a sand-filled soccer ball) and a soccer ball with the same force and measure how far they move. If Sir Issac Newton is right, the soccer ball which has less mass than the bowling ball, will move farther. (Be very careful handling the bowling ball. It could hurt your foot if it should fall on it. Have an adult help you if the ball is too heavy for you to handle safely.)

We need to have a force that will be exactly the same every time, so we can be sure each ball is struck with identical force. This is our Constant. To do this, construct a ramp with the long two 2-by-4 inch wooden boards, making a "V" shape. Rolling a golf ball down the "V" channel will cause it to strike whatever object is at the bottom of the ramp with the same force every time. If we let go of the golf ball at the same place on the ramp each time, the force of gravity will ensure that the ball is rolling at the same speed every time it reaches the bottom of the ramp.

Nail two 2-by-4 8-foot (240 cm) long pieces of lumber together, making a "V" shaped channel. This will be out wooden ramp.

Outside, set up a ladder. Rest one end of the ramp on the third or fourth rung of the ladder. At the ground end of the ramp, place a bowling ball so that it is touching the end of the ramp. The ground must be flat and level.

You'll get the most action if the bowling ball is struck in its middle, some small distance above the ground. Place books underneath the end of the ramp to raise it until it is positioned at the middle of the bowling ball. You may need to place a few books along the sides of the ramp to keep the "V" side facing up.

Pick a spot along the ramp to let go of a golf ball and start it rolling down the ramp. To get the most speed out of the ball, you can let it go from the high end of the ramp. Be sure, however, that you let the ball go from the same spot every time. Also, don't give the golf ball a "push" start, because you would not give it an even push every time. Just let go of the ball and gravity will start it rolling.

If a bowling ball moves when it is hit, use a ruler to measure how far it moved.

Now we want to see how far a soccer ball, which has much less mass, will roll when the same force is applied to it. The different masses of the two balls is the Variable in our project.

Release the golf ball. If the soccer ball moves a lot, it may be easier to use a tape measure, yardstick, or meterstick than a ruler to measure the distance it rolled.

If neither ball moved, increase the slope of the ramp by moving up one rung on the ladder, giving more speed, hence force. to the rolling bacll.

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: Repeat the experiment using different balls at the bottom of the ramp; try a baseball, and a tennis ball. Can you predict which one will roll farthest?

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