Water Cooler: Favorite summer activities are full of science
There’s lots of interesting science behind some of our favorite summer activities. Here are just a few examples.
Blowing bubbles
The basic ingredients of bubble solution are soap and water. When you blow a bubble through a wand that has been dipped in a soap-water solution, the solution traps your breath into a small air pocket.
If you dipped a wand into just water and blew on it, no bubbles would form. This is because water is made up of small molecules that love to hold onto one another. That’s how water is able to form droplets and small puddles on flat surfaces. The molecules hold each other into a round shape, kind of like a magnet.
Soap is a substance that makes water molecules spread out, which is why it is great for cleaning. When you blow air into the solution, a bubble forms because of this delicate balance between the water molecules wanting to come together, and the soap trying to spread them apart. The air or your breath will be in the middle, and around it water molecules get sandwiched between two layers of soap.
A bubble pops when the forces behind these layers are disrupted. When you pop a bubble with your finger, you are essentially poking a hole into these layers of molecules, which breaks them apart and allows the air to escape.
Flying kites
Why exactly are kites able to fly in the wind? Is it just because they’re light? That’s part of it. The body of a kite is called a sail, just like a sail on a boat. Sails are meant to catch the wind for a specific purpose. For a boat, the wind is caught to propel the boat in a certain direction. The sail of a kite is meant to catch the wind in order to lift the kite up into the air.
The sail of a kite needs one important element to help it fly – the tail. The tail slightly weighs down the bottom of the kite, making it tilt down at the bottom instead of lying flat. As air passes by the sail, this tilt helps the air push harder against the surface of the sail facing the ground than it does the other side of the sail, helping it stay in the sky. If the kite wasn’t tilted, it would fall to the ground because the air pushing the kite up and the air pushing it down would be of equal force.
Making ice cream
Do you throw salt on your driveway to melt the snow in the winter? You can apply this same science in the summer to make your own ice cream.
When you add salt to water, the freezing point lowers. Normally water freezes at 32 degrees Fahrenheit. Add some salt, and now it has to be colder to freeze the water. If water is as salty as the ocean, it has to be about 28.4 degrees Fahrenheit to freeze.
To make ice cream at home, you need two sealable plastic bags, one big and one small. Fill the small one with one-half cup of cream, one-half teaspoon vanilla and 1 tablespoon of sugar. Fill the bigger bag with four cups of ice and one-half cup of salt. Seal that up and shake for about 5 to 10 minutes, or until the cream turns into an ice cream consistency.
As the ice melts, it begins to draw in heat from its surroundings, in this case the cream. The melted salt water is actually colder than ice, causing the ice cream to freeze in just a few minutes.