For this saltwater density experiment, you’ll fill four clear glasses with water, then add salt to one glass, sugar to one glass, and baking soda to one glass, leaving one glass with just water. Then, float small plastic pieces or grapes in each of the glasses and observe whether they float or not. Saltwater is denser than freshwater, which means some objects may float in saltwater that would sink in freshwater. You can use this experiment to teach kids about the ocean and other bodies of saltwater, such as the Dead Sea, which is so salty people can easily float on top of it.
Kids will love shooting pom poms out of these homemade popsicle stick catapults. After assembling the catapults out of popsicle sticks, rubber bands, and plastic spoons, they’re ready to launch pom poms or other lightweight objects. To teach kids about simple machines, you can ask them about how they think the catapults work, what they should do to make the pom poms go a farther/shorter distance, and how the catapult could be made more powerful.
In this quick and fun science experiment, kids will mix water, oil, food coloring, and antacid tablets to create their own (temporary) lava lamp. Oil and water don’t mix easily, and the antacid tablets will cause the oil to form little globules that are dyed by the food coloring. Just add the ingredients together and you’ll end up with a homemade lava lamp!
If you’ve ever wondered why someone can measure and pour ingredients into a bowl, mix them up, and then bake the batter in the oven to make a cake, you’ve thought about science. The process of mixing certain ingredients together and adding heat causes the ingredients to react and change. For example, baking powder or baking soda in a cake recipe will react with acidic or wet things in the batter to puff it up and make the cake light and fluffy. Scientists tested these reactions so many times that they learned what would happen every time. This is called experimentation, and you can do it, too. 
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