You will need:
q Plastic bottle (more than 3/4th way full of water)
q Balloon filled with helium gas
q Car
q Empty parking lot
q Thread
INSTRUCTIONS
- Prepare your car for an interesting ride. Ask an adult to help you tie a helium-filled balloon somewhere in the car securely with the help of a string.
- Make sure the balloon does not come in the way of whosoever is driving the car.
- Place a plastic bottle horizontally in the car so that
the cap side may be facing the front of the car. - Now, request an adult to drive the car in an empty
parking lot where you will not hit anything or anyone by accident. - As the car starts and moves ahead, keep an eye on the balloon and the bubbles inside the plastic bottle of water.
- Ask your driver to slow down car and bring it to a halt. While the car is stopping, watch and observe the balloon and bubbles in the water carefully.
RESULT
As the car starts moving forward, we would be forced slightly backwards due to inertia. But the balloon and the bubbles do not follow the laws of inertia, and move forward with the car. Similarly while we move slightly forward when the car comes to a halt, the balloon and bubbles in the plastic bottle move backwards. The bubbles in the bottle behave differently because air trapped inside the bottle is less dense in comparison to water. When the car stops, they both keep trying to move forward, but water being denser than air pushes it backwards. Similarly, since the helium balloon is less dense than the air surrounding it, it too is pushed backwards when the car comes to a halt.
