Did you know that some substances will never mix together, no matter how hard you try? Scientists have discovered ways to use this fact to make some chemicals do all sorts of useful things—and even dance around! Today, you'll learn what keeps these chemicals apart, why things float (or don't), and how to create a special chemical reaction to make oil bubbles dance in water.
what you’ll need
- A computer, tablet, or mobile phone and access to the internet
- Pens, crayons, markers, or colored pencils
- A large, clear jar
- 2 cups of water
- 1 cup of vegetable oil
- 4 tablespoons of salt
Ask About Today
How would you explain "density"? When objects float, are they usually more dense or less dense than the liquid they are floating on?
If you could float in a tub full of anything, what would it be?
Skip the Ads
Unfortunately, online videos often start with short advertisements. Remind your campers to click the "Skip" button as soon as they can to move ahead to the video.
When you think about layers of liquid, you probably think about things like root beer floats, with the ice cream melting at the top and the root beer below (yum...). But did you know you can stack some liquids up like blocks? That's because some liquids have different "densities" than others. Check out this article to learn more and see some liquid stacking in action.
Think about these questions after watching the video:
1. Why do you think layers of different liquid were able to form in the container? Why didn't they all mix together?
2. Why do you think certain objects sank while other objects were able to float?
Go Deeper on Density
Density can be a tricky concept. Let's take another look.
Remember: Online videos often start with advertisements. (Annoying, we agree!) Click the "Skip" button as soon as you can to move ahead to the video.
How Do You Clean Up an Oil Spill?
Oil spills are a good example of how oil and water don't mix. Instead of dissolving in the ocean, the oil from a tanker ship or drilling rig instead sits on top of the water and spreads—sometimes for hundreds of miles. It's a huge mess that can do a lot of damage to wildlife. But scientists can also use the way oil behaves to clean it up. Find out how in this video from Discovery News.
Dance of the Oil Bubbles
We loved Dance Revolution week so much that we wondered if we could make chemicals dance, too. Turns out, we can—and you can, too!
To get started, you'll need an empty jar, water, a cup of vegetable oil, and some salt. (Younger kinda campers will also need some help from an adult.)
Once you have your supplies, click the button and follow the directions to begin the dance of the oil bubbles.
We’ve only talked about liquid density so far, but did you know you can even determine the density of where you live? Start by reviewing the photos and vocabulary, then read to learn how density shows up in other areas of our lives.
How Do Boats Float?
Wait, if things like metal are denser than water, why don't giant boats made out of metal sink straight to the bottom? Let's find out with Wonderopolis.
Floating on the Dead Sea
The Dead Sea seems like the perfect vacation spot for a mad scientist. For one thing, it has a creepy name. For another, it is super salty—which makes it denser than normal sea water and easier for people to float in. Learn more and see what it's like to swim in it.
For younger explorers
What Floats? What Sinks?
Read along to find out!
Ice floats in water because it is less dense! But today, we're worried about ice for a whole other reason—because it's threatening Ruff's plushy! Can you help save the day?
For younger explorers
Join Sid The Science Kid in a fun measurement game, Crystals Rule! In this game, you'll help Sid measure big rocks with smaller objects.
Mix and Move
Take a break from mixing chemicals and start mixing some dance moves with this fun workout. Get your water and go!
more to explore
Have you been enjoying Little Alchemy? With this online tool from Chicago's Museum of Science and Industry, you can try combining every element on the periodic table. See what you can create—but be careful, some combinations may create strong reactions!
Eat Your Water Bottle
Chemists and other scientists come up with pretty amazing inventions, like this water bottle you can eat.
Did you like making oil dance? You'll love making gummy worms do it. Give this one a try if you have the ingredients around the house!