Can wind travel around an obstacle? Watch and find out!
What you need: a candle, a match, a tall square object like vase, and a tall round object like a drinking glass
What you do:
- Set the candle at a height so your mouth is at the same level as the flame. Use a sturdy pillar candle, or stick a birthday candle in a piece of playdough so it won’t fall over.
- Set the square vase between you and the candle. With your mouth very close to the vase, blow hard. The vase blocks the wind, and the candle doesn’t go out.
- Now try the round glass. The candle should be a few inches behind the glass, and your mouth should be quite close to the glass.
- Blow hard at the glass - the wind will travel around the glass and put out the candle!
Questions to explore:
- How can the wind blow out the candle, when the glass is in the way?
- What happens if you use a square object instead of a round one - does the candle go out?
- Does the wind always blow in a straight line, or can it go around something?
Why it works (or Other Variations to try)
In the video, we saw wind go around the glass and put out the candle. Remember how wind is just air moving from one place to another? We can’t see air with our eyes, but with experiments like this one, we can see how it moves. The glass is a smooth curve with no corners, so the air can travel around it, just like water flows around a rock in a stream. The vase, on the other hand, has a square side with a sharp corner. The air hits it and can’t slip around the corner to reach the candle. Try different objects and see which ones the wind can get around!