This egg race project teaches about physics concepts like force, friction, and gravity. Customize your egg and/or your ramp and see how it changes your results.
What You Need:
- Plastic eggs
- Cardboard box
- Sharp scissors or knife
- An adult to help
- Packing tape
What You Do:
- Ask an adult to carefully cut the flaps off of your box with sharp scissors or a knife.
- Make a long ramp by taping the short ends of the flaps together using packing tape. It should measure at least two feet long for best results.
- Fold each long side of the ramp up 1-2” to help keep your moving egg from rolling off the edge!
- Find a spot to try your ramp—prop one end up on the edge of a chair or sofa with the other end on the floor.
- Get your stopwatch ready and start it as you set the egg on its side at the very top of the ramp. Stop the stopwatch as soon as the egg reaches the bottom. You may have to try it several times to get an accurate time (or ask someone to help you watch the egg while you time it).
- Now find another spot to prop the ramp—try something that is lower to the ground than your first spot and time the egg again. Compare the time it took at the first height and when you placed the ramp lower (at less of an incline).
- Repeat step 6 with another location that is even higher than your first test and compare the times from all three heights.
Variation: Instead of using a stopwatch, you could make two ramps of the same length and race plastic eggs down them with a sibling or friend. Try putting both ramps at the same level of incline, then changing only one ramp, and then try putting different objects inside your eggs to see if the speed at which they travel down the ramp changes!
You created a ramp out of the cardboard flaps. A ramp is a type of simple machine called an inclined plane. Using an inclined plane reduces the amount of work (force) needed to move an object upwards. However, we used the ramp in this example in the opposite way—to move objects downwards! When a ramp is placed at different heights, the time it takes for an object to move down the ramp changes. At what angle did the egg move the quickest down the ramp? When the ramp’s angle was steep, the egg made it to the bottom faster than when the ramp’s angle was lower to the ground, right? Do you know why?
There are a few forces that affect the egg’s motion down the ramp. The first is gravity. Gravity is pulling down on the egg and is what allows it to move so quickly to the bottom. The second force is friction. Friction is actually acting against the egg. When the ramp had a lower angle, the negative effect of friction was stronger causing the egg to slow down a bit more than when the ramp was at a higher angle. Because the egg and the ramp both have a smooth outer surface, there was not much friction acting on the egg in this situation. Do you think it would be different if your ramp had been covered in something with a rough surface, such as sandpaper? What if the egg had been a square block rather than a round shape? You can test those theories out if you like by trying different materials and objects on your ramp.