To put it simply, how much of something can fit into a container or space? If we figure that out, we know the substance/object's density! Many science concepts are hard to understand for kids, but density is excellent because it is very visual.
From liquid density experiments with food coloring to ping pong balls dropped in vegetable oil, we have all the whacky experiment ideas that will get your mini mad scientists jazzed about mass and volume.
1. What's The Heavier Liquid?
To understand the concept of density in all of its forms, it helps to start with liquids we can easily differentiate. This fun experiment uses a glass of water, vegetable oil, food coloring, and salt.
Learn more: Buggy and Buddy
2. The Floating Orange
Here is a simple science experiment that teaches an important lesson about density. Grab 2 oranges, peel one and leave the skin on the other. Fill 2 glasses with water and put each orange in a cup. Watch your kid's eyes get huge as they see the peeled orange sink and the unpeeled orange float!
Learn more: School Science Experiments
3. Burning Candle Density Experiment
Carbon dioxide has a higher density than air, so for this cool density experiment, you'll want to have 3 candle sticks that are different lengths. Place them close together and light their wicks, then cover all 3 with a small glass container. Notice how the shortest candles go out first!
Learn more: Collection of Physics Experiments
4. Liquid Rainbow of Density!
For this density demonstration, you'll have to prepare some liquids from your kitchen and bathroom. The liquids make distinct layers in the clear jar due to their different levels of density.
Learn more: Raising Dragons
5. Density-Inspired Sensory Bottles
Before you start this fun science experiment, explain the steps to your kids and help them come up with some questions and hypotheses about what they think will happen. Using 2 clear individual containers, fill one with water and one with corn syrup and leave some space for air, then add a few dense objects like buttons or rubber balls. How do the objects move in each liquid?
Learn more: The Educators' Spin On It
6. Float or Sink?
The beginning of this experiment for kids starts with adding different liquids to a clear jar. Some you can try are honey, water with food color, and cooking oil. Then grab a variety of household items small enough to fit inside, and see where they settle in the layers of liquid density!
Learn more: Looking Out Loud
7. The Science of Grapes
Whether your kiddos like green or purple grapes, they will definitely LOVE this fun density experiment! We are testing to see if there is a difference in buoyancy in salt water versus tap water. Fill 2 glasses of these different water types and drop some grapes in. Which will sink and which will float?
Learn more: Rookie Parenting Science
8. Popcorn Mixing Magic!
To demonstrate how denser objects behave compared to lighter ones, we can do this exciting experiment using un-popped popcorn in a clear jar. For the light ball, you can use a ping pong ball, and the heavy ball should be metal for best results.
Learn more: Steve Sprangler
9. Can Eggs Float in Water?
You can teach your kids the science of density while preparing breakfast! Put water in 3 clear plastic containers and mix salt in one, sugar in another, and leave the 3rd alone. The 4th cup will have saline water. Grab 4 eggs and have your kids carefully drop an egg into each cup to see if they sink or float!
Learn more: Go Science Girls
10. The Density of Planets
The science of space for kids starts now! Out of all 8 planets, the least dense is Saturn. To explain this idea to your kids, the first step is to go outside and collect 7 small rocks together. Then your little artists can paint them to look like mini planets. To demonstrate, fill a kiddy tub with water, drop in your rocks, and watch them sink. For Saturn, use a foam or light ball that will float.
Learn more: Rainy Day Mum
11. The Beach in a Jar
Using our knowledge of density, we can create the layers of the beach inside a jar! From the sand to the sea floor, all the way up to the fluffy clouds. Check out the link to see how to assemble this simple density experiment.
Learn more: Lemon Lime Adventures
12. Sugar Rainbow Density
There are 6 colors in the rainbow, so put a teaspoon of sugar in 6 small cups. Grab your food coloring and add a few drops to the sugar then add water and stir. Using a syringe, add a little bit of liquid from each cup and watch how they make rainbow layers in the tube!
Learn more: Teach Beside Me
13. DIY Lava Lamps!
Did you know the far-out science behind lava lamps isn't that hard to recreate? Using corn syrup, water, Alka Seltzer tablets, oil, and food coloring, you can help your kids make their own!
Learn more: Babble Dabble Do
14. Ocean Layers Experiment
There are 5 layers in the ocean and each has its own density. To create an ocean-themed density jar, you'll add each liquid to the jar from most dense to least dense. Make sure each liquid has blue or some food coloring mixed in.
Learn more: Darcy and Brian
15. Racing with Marbles
For this exciting race, you'll want to fill a few clear glasses with different liquids, some options are baby oil, corn syrup, honey, or shampoo! First, have your kids guess just by appearance which liquid they think is the densest. Then drop your marbles in and see in what order they sink!
Learn more: STEAM-Powered Family
16. Temperature and Density Experiment
Which is more dense, hot water or cold water? Well, turns out that because hot water molecules move faster this makes them less dense. So if you add different food coloring to hot water and cold water, pour the cold water into the jar first, then add hot water, the colors will stay separate!
Learn more: STEAMsational
17. Colorful Water Fireworks!
So the trick to this experiment is mixing the food color and oil together first, then pouring it into your warm water to create an awesome color show in a jar!
Learn more: Go Science Kids
18. Balloons of Density
Grab some balloons and get testing to help your kiddos better understand the 3 states of matter as well as their varying densities! Fill 3 balloons, 1 with air, 1 with water, and the 3rd with frozen water. Have your kids pick each balloon up and see which is the densest!
Learn more: 123 Homeschool 4 Me
19. USA Inspired Density Tower
Here is a density tower your kids can drink! There are a few different liquid options you can choose from that are blue and red to create your patriotic concoctions.
Learn more: Steve Spangler Science
20. Earth's Atmosphere Density
Not only is this a lesson in density, but also your kids can learn more about the 5 layers of the Earth's atmosphere and how they settled in the pattern they did.
Learn more: Line Upon Line Learning
21. Density in Clay
This fun and simple lab experiment is for kids a bit older that have access to measuring tools, clay, and a few small objects. Make sure their items are the same size and shape them and cover them in clay. Put them in water and see how their density will make some sink and others float.
Learn more: Engaging Science Labs