Floating on Water: Paper Clips and Surface Tension
Time needed: 10 minutes
Difficulty level: Easy
Age range: 6+ years
Adult supervision: Recommended
Difficulty level: Easy
Age range: 6+ years
Adult supervision: Recommended
What You'll Learn
Discover the amazing properties of water's surface tension as you make metal paper clips float on water. You'll learn about the forces that hold water molecules together and how insects like water striders use this property to walk on water.
Materials Needed
Materials collected: 0/6
Clear bowl or dish
Several paper clips
Water
Fork or spoon
Liquid soap
Optional
Paper towels
Safety Notes
Be careful handling paper clips as edges may be sharp
Keep water away from electronic devices
Step-by-Step Instructions
1
Fill the bowl with water nearly to the top
2
Place a paper clip carefully on the spoon
Lower the spoon with paper clip just below the water's surface
3
Gently slide the spoon out from under the paper clip
Watch as the paper clip "floats" on the water's surface
4
Optional: Add a tiny drop of soap to see what happens
Watch It In Action
See this experiment demonstrated step by step in this video. Watch how carefully the paper clip needs to be placed on the water's surface to achieve the floating effect, and observe what happens when soap is added to break the surface tension.
The Science Behind It
Water molecules stick together at the surface, creating a "skin" called surface tension.
This same property allows water strider insects to walk on water in nature.
Soap breaks the bonds between water molecules, weakening surface tension and causing the paper clip to sink.
Common Questions
Why does my paper clip keep sinking?
Try placing it more gently on the surface, and make sure your hands and the paper clip are completely dry.
Will all sizes of paper clips float?
Smaller paper clips work better than larger ones, as they're lighter and disturb the surface tension less.
Does water temperature affect surface tension?
Yes! Warm water has slightly lower surface tension than cold water, making it harder for paper clips to float.
Take It Further
- Try different sizes and shapes of paper clips
- Experiment with warm versus cold water
- Test other small metal objects
- Compare different types of liquids
Related Experiments
If you enjoyed this experiment, try these next:
- Pepper Dance: Surface Tension Magic - Another experiment with water's surface tension
- Colorful Density Currents - Explore other amazing properties of water
