What better way is there to learn about surface tension and water molecules than by playing with bubbles? Kat and I have been having a lot of fun exploring the different ways that liquids interact with each other, and the reactions that can take place. This time, we decided to explore surface tension by learning about how bubbles work! Even better, we've taken our lesson to the park and have invited the other kids to come along and learn with us!
The first thing we had to do was talk about surface tension. We've played around with the surface tension of various liquids before, but we still didn't quite understand what it actually meant. After trying several different explanations, we came up with a fantastic way to illustrate it.
Let's think of a water molecule as a little teddy bear. We'll give it 2 Hydrogen ears and 1 Oxygen nose (this is a pretty nice visualization of H2O). When water is in its liquid form, all these little teddy bear water molecules want to hang out and play together. When they look up, down, left, and right, all they see are more teddy bear molecule friends. There sure are a lot of them! All these teddy bears are really happy. They get to relax, hang out, and have pretend tea parties. In the water, life is great.
|If bears could hang out as water molecules, this is totally what they'd look like.|
Near the surface, however, things are a little different. For these teddy bear water molecules, life is great as long as they don't look up. If they look down, left, and right, they've got lots of teddy bear water molecule friends. However, if they look up, everything is different! This freaks them out. They want to be with their friends and join in the fun and stay in their liquid bubble forever and ever! They cling together, and buzz around with a lot of energy, constantly trying to get close in a little bubble of liquid playtime. This energy causes the surface tension that we are so familiar with. When an insect lands on the top of a pool of water, it can walk around on it because of all of the buzzing and jiggling molecules that are vibrating near the surface.
Now, this is great for understanding surface tension, but what does this have to do with bubbles?
Have you ever tried to blow bubbles out of plain old tap water? The surface tension is too strong, you can't do it! However, if you add a detergent, such as dish soap, the molecules will slide in between the water molecules, breaking that surface tension. Some of the atoms in the soap molecules really like water (hydrophillic), and some of them really don't (hydrophobic). The atoms that don't like water will squeeze in between the surface water molecules, breaking through until they're as far out of there as they can go. Because of this, the soap will form a thin layer around the water, which will help protect the water from evaporation. This is why you're able to blow bubbles once you add soap to your water.
|Not only do you get bubbles, but you get a beautiful display of the spectrum of light!|
Now that we understand how and why bubbles work, let's see if we can find a really great recipe for blowing bubbles!
1. A big bottle of Johnson and Johnson's baby shampoo
2. Glycerin - You can find this in the skin care section of most pharmacies.
4. Liquid Dish Soap
5. 1 package of unflavored gelatin
6. A shallow pan - We used a shallow baking pan and some Tupperware.
7. Bubble blowing utensils! We used small bubble wands, funnels, coat hangers, pipe cleaners, and milkshake straws. Get creative, and see what you can find to make bubbles with!
|You can make these bubble tunnels too!|
Before you start mixing your bubble solutions, you'll want to start making some bubble blowing utensils. Some of the best ones we came up with were made out of pipe cleaners, yarn, and straws. We took 3 pipe cleaners and connected them into a circle. Make sure that there are no sharp metal points sticking out of the connected ends of the pipe cleaners. These worked really well for making long bubble tunnels.
We also found that milkshake straws worked really well! We found them at our local grocery store, in the beverage section. They are thicker and wider than regular straws, but I'm sure any straw would work well for this. We fed a long piece of yarn through four milkshake straws and then tied them together so that it formed a square. When you dip this into the bubble solution, you can close the square to cut off the bubble tunnel to form large spherical bubbles.
Now for making your bubble solutions!
Using these ingredients, we made several different batches of bubble mix, and played around until we found some that worked really well. The glycerin, gelatin, and baby shampoo are very important ingredients, so don't leave them out!
For a decent bubble mix that is comparable to what you would get at the store, mix 1 part water to 1 part baby shampoo, and add about 1 Tbsp of glycerin. This will get you going with your small bubble wand, or any other bubble blowing accessory you have on hand.
For a thick bubble mix that will get you making large bubble tunnels, mix 2.5 to 3 parts baby shampoo, 1 part dish soap, and 2 Tbsp of glycerin. This was what we used at the park with the kids, and it was a HUGE success! All of the kids (ages 4-7) were able to make big bubble tunnels. They were thrilled, their parents were happy, and it was all non-toxic!
Finally, we used a different method for making really big bubbles and large tunnel bubbles. Apparently, this recipe will also make really strong smaller bubbles that can bounce off your clothes! We did not test that out as we were have so much fun making the gigantic bubbles. This was our favorite recipe, and we're going to have to make it again to so the kids at the park can try this one too!
Here's the recipe:
1 pkg unflavored gelatin
1 cup of hot water (just boiled)
2 ounces of glycerin
8.5 ounces (just over a cup) of baby shampoo
Dissolve the gelatin in the hot water. Add the shampoo and the glycerin. Stir gently. This solution will cool to a usable temperature rather quickly. It will begin to gel if it gets too cold. If it does get too cold, you can reheat it in the microwave for about two minutes. However, we didn't experience the gelling, as we used it all pretty quickly!
As you can see, the pipe cleaner worked out really well. This recipe yielded really strong bubbles that were able to withstand the wind and the high temperatures we had.
This is what we were able to get with our milkshake straw circle! We were able to bend it so that it would fit into the pan with the mixture, and once the bubble got to a nice size, I closed the square off, and the bubble jiggled itself into a sphere, which is where those molecules wanted to be all along.
We spent hours playing with our different types of bubble mix. However, once we began to run out, the recipes went out the window! We added more dish soap, additional glycerin, and more baby shampoo. I have no idea what the amounts were, but they definitely prolonged our bubble mixture! I'm sure that as you go out and play with these, you'll end up experimenting with different ingredients and measurements to see how much bubble power you can get.
Of course, if you find a really great bubble recipe, please share in the comments! This was a huge hit at the park, at our house, and with our neighbors. I'm sure you will have just as much fun with this as we did, and more recipes would definitely be appreciated!
Have fun, and happy bubble making!