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DISCLAIMER
Neither Future Publishing nor its employees can accept any liability for any adverse effects experienced during the course of carrying out these projects or at any time after. Always take care when handling potentially hazardous equipment or when working with electronics, and follow the manufacturer’s instructions.
SUMMARY
How does setting a tea bag alight propel it upwards? It’s all due to how heat impacts the surrounding air. As the flame heats the air molecules inside the tea bag, they become more energised and move around faster. As they move, they spread apart and move up and out of the tea bag. Because the air molecules are being lost from inside the bag, the density of the air is reduced.
Relative to the denser air surrounding the tea bag, the tea bag itself becomes lighter. The air inside the bag starts to rise above the cooler air outside of it, carrying the tea bag with it. The tea bag continues to burn, producing lightweight ash. Eventually the bag will be completely burnt and the fire will run out of fuel. With little to no wind, the ash should fall back onto the tinfoil launchpad mat you prepared beforehand.