A salt volcano is a simple science experiment which has a super high groovy factor. Your kids want their science projects to be colorful, dazzling and immediately gratifying. You want them to learn something about the amazing natural world. Well, a salt volcano is where it’s at, man.
While they are making a salt volcano, kids will learn about liquid density and you will experience 1970s déjà vu. You will dream about orange shag carpets, hanging bead curtains and your beloved lava lamp!
Let’s get started!
What you need:
A bottle or jar
One cup of room temperature water
1/4 cup vegetable oil
Salt; rock salt works best, but table salt will also work
Optional: food coloring
Salt Volcano Instructions:
1. Pour water into the jar.
2. If using food coloring, add it now.
3. Pour in the oil. Do not mix!
4. Sprinkle the salt into the jar.
5. Observe what happens!
Salt Volcano Science:
Water and oil are immiscible liquids. That means they don’t mix. When you sprinkle the salt into the water-oil mixture the salt sinks to the bottom. As it sinks, the oil clings to it. When the salt reaches the bottom, it will begin to dissolve and as it does so, the oil that was on the salt rises to the top.
This experiment teaches kids about density. Oil is less dense than water, which is why it floats on the surface, and why the escaped oil from the salt wants desperately to reach the top again. Salt denser than water, which is why is must sink to the bottom.
Salt Volcano Variations to Make It Even More Fun:
We had fun experimenting with the food coloring. Instead of adding the color before the oil, try adding it after and watch what happens. Will you wait until the color mixes to add the salt, or will you add them at the same time? What changes when you use smaller or larger salt crystals? Does it matter if you add more or less water?
Experiment!
The Salt Volcano is also a great classroom project for STEAM curricula! Our STEAM Kids book is chock full of STEAM projects just right for 4-8 year olds. You will definitely not want to miss out on the amazing ideas inside it!
eBook | Amazon Print | UK/EU customers: eBook
More science to try:
- Water Refraction Science Experiment
- Kid Science: Homemade Bottle Thermometer
- The Colorful Cabbage Juice Science Experiment
Jenny says
October 22, 2008 at 7:13 pmCJ has no interest in concepts either. I’ve been looking for a good science book myself to no avail. Be sure and post if you find anything Kiddo really likes, and I’ll keep looking too. Hopefully one of us will find something decent!
Anonymous says
July 26, 2012 at 5:00 pmHave you tried the mentos and soda rockets? My son is four and loved that experiment.
Mom and Kiddo says
July 26, 2012 at 5:53 pmI haven't. It sounds fun!
Haley says
August 9, 2013 at 4:31 amLook forward to trying! You should try the exploding bags with baking soda and vinegar. So much suspense and giggles and i did with 2 and 4yrolds.
Erica MomandKiddo says
August 9, 2013 at 9:24 amI love that idea, Haley. We’d have to do it at the park, though since we don’t have a yard.