Summary
Introduction
Have you ever tried to catch a bubble without popping it? It's hard! What materials can you use to successfully catch a bubble? Do some materials work better than others? Try this activity to find out.
Materials
- Bubble solution. You can buy some or make your own at home with water (preferably distilled), dish soap, and glycerin or corn syrup (see Prep Work section).
- Small bowl or container to hold your bubble solution if you make your own
- Bubble wand
- Different materials to test such as aluminum foil, wax paper, printer paper, plastic wrap, wood, plastic bags or food storage containers, metal pots and pans, tables, counter tops, etc. You can try any material that you can find around your house!
- Tap water
- Paper towels
Prep Work
- To make your own bubble solution, mix 1 cup of water with 2 tbsp of dish soap and 1 tbsp of glycerin or corn syrup.
- Cut sheets of the different materials you want to test. Lay them out on a flat surface, preferably indoors. It will be difficult to do this project outdoors on a windy day.
Instructions
- Dip your bubble wand in your bubble solution and gently blow some bubbles towards your first sheet of material. Try to get them to land on it and not go past it. This can take some practice, so try it a few times. What happens when the bubbles hit the surface?
- Try blowing bubbles onto each of your other materials.
Do any of the bubbles land without popping? - Get a paper towel wet and use it to wipe a thin layer of water onto each surface. Note: you might not want to do this part with certain materials, like wood or furniture, as water could damage them. Check with an adult if you aren't sure.
- Try blowing bubbles onto each surface again. What happens now?
- Dip a new paper towel into your bubble solution, and wipe a thin layer of it onto each surface.
- Blow bubbles onto each surface again.
Do the bubbles stick to any surfaces where they previously popped? Do they last longer after they land?
Cleanup
What Happened?
When all your materials were dry, you probably found that smooth, waterproof surfaces did the best job catching bubbles. Wax paper, plastic wrap, and aluminum foil all work well. Materials that absorb water, like paper, probably caused the bubbles to pop because they quickly soaked up the water in the bubble. You might have been surprised to find that other seemingly smooth, waterproof surfaces, like a plastic container or a steel frying pan, couldn't catch the bubbles without popping them. Even if these materials seem similar to you (for example, an aluminum pan and a steel pan might look very similar and both feel smooth), they might have microscopic differences in their surfaces that you can't see, and they are made from different molecules that may be more or less attracted to the water in the bubbles. You might have been even more surprised to find that some rough or absorbent surfaces, like carpet, could also catch the bubbles. Carpet is made up of lots of individual tiny fibers. When a bubble lands on the carpet, it touches many of these tiny fibers at once, so they can hold the bubble up without popping it like a single fiber would.
When you got the surfaces wet, especially with soapy water, it should have become much easier to catch the bubbles. The water forms a thin film on top of the solid surface, preventing the bubble from touching the solid directly. This can greatly extend the life of the bubble.
Digging Deeper
Bubbles are fun and beautiful—but also fragile! Bubbles are made from a thin film of soapy water with air inside. Many different things can cause this film to break, popping the bubble. Bubbles will frequently pop when they come into contact with a solid surface, but they can even pop without touching anything, as the water in them gradually evaporates and the film gets weaker. However, sometimes you might notice that bubbles can land without popping.
Whether a bubble pops when it comes in contact with a solid surface depends on many different factors, including the surface properties of the material. You probably know that different materials have different properties, some of which you can see or feel (like color or density). However, materials have some other properties that are harder to observe directly. Surfaces can be hydrophobic (repel water) or hydrophilic (attract water). You can observe this by dropping some water onto the surface and seeing whether it forms big beads (hydrophobic) or spreads out in thin sheets (hydrophilic). Whether a material is hydrophobic or hydrophilic depends strongly on its surface roughness. Some materials, like sandpaper, have macroscopic surface features, meaning you can feel the bumps and see them with your naked eye. However, other materials have microscopic surface features. Even if the material looks and feels smooth to you, it might have very tiny bumps or pores. These can actually help the material repel water, because the surface of the water, held together by surface tension, is unable to penetrate into the tiny gaps in the material. Other materials, like paper or sponges, have larger gaps that help then absorb water.
All of these properties, along with other factors like how fast the bubble is moving and whether the surface is wet, can affect whether a bubble is more likely to pop when it lands.
Ask an Expert
For Further Exploration
- Does the orientation of the surface matter? Try using some tape to put your materials on a wall or even on the ceiling. Can you still get bubbles to land on them?
- Try different recipes for a homemade bubble solution (see Additional Resources section). Which bubbles are easiest to catch?
