Show kids the magic of hot air movement and convection with this simple experiment. Younger children may need adult supervision as it uses heat from a candle. You will need the following:
- Bamboo skewer
- Cup filled with sand / soil / clay or anything that would hold the bamboo skewer up.
- Tealight candle that would fit in the cup with the skewer
- Aluminum foil
- Marker
- Scissors
- Lighter
How to do it:
- Using a marker, draw the above image on the aluminum foil to create a spiral snake.
- Cut out the shape with scissors.
- Fold the tail end of the snake on the tip of the bamboo skewer.
- The final snake should not be longer than the bamboo skewer and should not touch the flame.
- Light the tealight and wait a few seconds for the hot air to rise.
- Watch the snake spin.
Science behind it:
When air is heated, molecules start to move faster and farther away from each other making it expand. This means, hot air becomes less dense than cold air and it starts to rise above cool air. Convection is the movement of hot air and cool air — hot air rises and cool air flows to replace it. Then, the cool air gets heated by the candle and that moves up again, repeated the process and creating a current that moves the spiral snake.
Watch how we did it in this video:
Activities for Kids at Home 