Ready for a hands on experiment that will thrill kids while also demonstrating the power of density differences and convection currents? This Flying Ghosts Science Experiment is perfect for Halloween or any time of year, as part of a thermodynamics study. Simple and quick to do, kids will be asking to do this flying tea bag experiment over and over again.
Flying Tea Bag Heat Science Experiment
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When you do this experiment your kids will probably think it is a trick. Like our Why Does It Rise? Water Experiment. It is so incredibly cool, kids will be obsessed and want to send ghost after tea bag ghost flying through the air! But this is no trick. It is actually a really fascinating experiment demonstrating the science of heat.
Flying Tea Bag Supplies
Tea bags – You want the type with tags that fold over. I used Twinnings and Stash brands with perfect results
Baking Sheet or other heat proof surface
Surface protector, like parchment paper for using sharpie
Whenever working with any fire in a science experiment you need to ensure you have proper adult supervision, a safe, fire proof work area, and a fire extinguisher. Always put safety first, even with relatively safe experiments such as this one.
In our experience the ghosts launched 5 to 6 feet into the air. Ensure you have plenty of ceiling clearance.
Halloween Flying Ghosts Science Experiment
Check out our video of this fun experiment. If you can’t see the video, please turn off any adblockers as they also block our video feed.
Carefully snip the string holding the tag of the tea bag and remove it.
Fold open the tea bag and empty all the tea into a bowl.
Smooth the tea bag out and place it on a sheet of parchment paper before drawing on your ghost faces and designs with a marker. It will bleed through, so ensure you protect your table top surface.
Once your designs are finished, use your fingers to carefully open up the tube, then stand it up on the baking sheet.
When you are ready, light the top with a lighter. It should catch fire quickly. Step back and prepare for the flight.
It will burn down, then as it reaches the base it will lift off and your ghost will take flight!
After the Flight
After it takes off, the ghost tea bag will shoot into the air, then the ashy remains will gently float back down to the baking sheet. They are very light and therefore susceptible to air currents. If you hold your hand still the ash may fall back into your hands. Don’t worry, it is perfectly cool by this point!
So how exactly are our ghosts taking flight in such a spectacular way?
When you light the tea bag, the heat from the fire causes the air molecules inside the tea bag to become energized and move around quickly. The air molecules inside the tea bag are moving so fast that they spread up and out of the tea bag. This makes the air inside the tea bag less dense, or less tightly packed together, than the colder (more tightly packed together) air outside of the tea bag.
Density is the measurement of how compact (or tightly packed together) something is. In our experiment fire and heat from the fire, causes the air molecules to spread out and become more active, therefore they are less dense.
Warmer, less dense air rises above cooler, denser air.
It is the density difference between the warm and cool air that causes the ghostly tea bag to fly. The warmer, less dense air inside the tea bag rises up above the cooler, denser air. As warmer air moves up, colder air moves in to replace it. This causes a thermal convection current to form that lifts up the tea bag. Then your ghost flies away!
The ash is VERY light and susceptible to air currents. If you wait patiently, without disturbing the air, the ash should fall right back onto the cookie sheet. Or you can catch it in your hand.