Here is a visually effective procedure that will help kids grasp the basic convection current phenomenon in physics. Adult supervision is a must for the homemade rocket.
Tea Bag Rocket Science Experiment
Hypothesis
On lighting an empty cylindrical tea bag from the top, it flies upwards resembling a rocket.
Materials
- Tea bag
- Non-inflammable plate
- Lighter or match
Instructions
- Remove the staple, string, and label from the tea bag.
- Clear off the tea from inside.
- Unfold the bag and spread it out.
- With your fingers, prop its inside to make it stand as a cylinder on the plate.
- Use the lighter to ignite its top.
- Wait for a few seconds to watch your rocket take off.
If you want, instead of step 1 you can cut off the top of the tea bag with a pair of scissors.
Tea Bag Rocket Video
How Does It Work: Explanation
The fire on top heats the air inside the tea bag, making it less dense (lighter) than the surrounding air outside. Due to convection, lighter air tends to move upwards while cool, dense air comes down to take its place. As a result, the tea bag flies up. As the flame reaches the bottom of the bag, it turns into ash and decreases in its mass. This aids the uplifting process even more.
The same principle is utilized in hot air balloons. A flame is lit at the base of a hollow balloon that heats up the air inside making it less dense than atmospheric air and raising it up in the process.
Magic tea bag rockets can be used as either a lab demonstration or a science fair project. Owing to its simplicity, the trick can be done at home to make science interesting for kids.
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