When you want to measure how fast a ball rolls, there are some easy and fun ways to do this. Here are a few methods you can try:

1. Stopwatch

Using a stopwatch is simple. Here’s how you can do it:

• Set a distance: Put two markers a certain distance apart on the ground. For example, you can choose 5 meters.

• Release the ball: Let the ball roll from the first marker to the second without giving it a push.

• Time it: Start the stopwatch when the ball passes the first marker, and stop it when it gets to the second marker.

• Calculate speed: To find the speed, use this formula:

  $\text{Speed} = \frac{\text{Distance}}{\text{Time}}$

  For example, if it took 2 seconds to roll 5 meters, the speed would be:

  $\frac{5 \text{ m}}{2 \text{ s}} = 2.5 \text{ m/s}$

2. Tape Measure and Markers

Instead of just using markers, you can use a tape measure for more accuracy. This way, you can adjust the distance to see how it affects the ball’s speed.

3. Ramp and Protractor

If you want to try something a little more complex and see how gravity works, you can create a ramp:

• Make a ramp: Use a plank and tilt it at an angle. Measure how high it is and how long the flat part is.

• Time the ball: Use the stopwatch again to see how long it takes the ball to roll down the ramp.

• Just like before, use the speed formula to figure out the speed!

4. Video Recording

If you like using technology, you can record your experiment with a smartphone. Watch the video later and count the frames to calculate the speed exactly.

Trying out these different tools is not only exciting but also helps you learn about forces and motion!