Materials
- 5 matchsticks or wooden toothpicks
- Flat, non-absorbent surface (plate or petri dish)
- Dropper or straw
- Water
Instructions
- Carefully bend each matchstick in half. Do not break it completely. The wood should still be hinged.
- Arrange the bent matchsticks on the flat surface in a small circle. The open ends of each V-shape should touch the next one, forming a closed shape in the center.
- Use a dropper or straw to place a few drops of water directly into the center of the formation.
- Make sure the water touches the bent section of each matchstick.
- What you will observe: Within seconds to a minute, the matchsticks begin to move. The bent arms slowly push away from each other, opening up and forming a clear, five-pointed star shape.
What’s going on?
- This experiment demonstrates capillary action and surface tension.
- The matchsticks are dry at first, so the bent wood stays tightly folded. When water is added, it is pulled into the tiny spaces in the wood by capillary action.
- As the wood absorbs water, it swells slightly. This swelling causes each bent matchstick to straighten. Because all the matchsticks are connected in a circle, they push against each other as they open.
- Surface tension holds the water together and helps the water spread evenly to each matchstick, allowing the movement to happen smoothly and at the same time.
Tried this experiment?Please consider Leaving a Review!
So fun! The kids loved it.