Third Grade STEM Activities for Kids (223 results)

Build a Cooler

STEM Activity

137 reviews

How does a cooler keep things cold? Which material makes the best insulation? Try this project to find out how long you can keep an ice cube from melting once it's out of the freezer! Read more

Candy Camouflage

STEM Activity

144 reviews

Have you ever wondered how predators, like wolves, lions, and hawks, are able to find their prey? And what can an animal do to stay off of a hunter's menu? To survive, some animals have developed specific camouflage tactics to fool their predators. One strategy some animals use is to look very similar to other animals that are poisonous or that the predator doesn't like to eat. This camouflage tactic is called mimicry. In this science activity, you will be the hungry predator and you will hunt… Read more

How to Grow the Best Crystals

STEM Activity

140 reviews

Have you ever wondered how crystals are made? Crystals come in all different shapes and sizes. However, the purest and cleanest crystals are usually also the ones that grow to be the largest in size. In this activity, you will compare the size and shape of crystals grown at different temperatures. With just water and Borax, a household cleaning product, you can discover the method for growing large, pure crystals! Read more

Featured

Make String from Algae

STEM Activity

225 reviews

Did you know that the seaweed you've seen in the ocean or even eaten as a snack is inspiring innovators to imagine new materials? Large brown algae, like kelp, contains polymers—long chains of molecules—that are more environmentally friendly than the ones in most plastics. These natural polymers (alginates) could eventually be used to create sustainable everyday objects. Try your hand at using a bit of chemistry to turn biodegradable polymers from algae into your own custom… Read more

Hydroponics Made Easy

STEM Activity

145 reviews

Do you think plants can grow without soil? If you've tried growing vegetables, you probably planted the seeds or seedlings in soil. Soil gives the plants the nutrients they need to grow. However, plants can grow without soil, too, using a process called hydroponics. In this activity, you will transform a bottle into a mini-garden that needs only light, air, and nutrient-rich water to grow! Read more

Make Your Drawings Float!

STEM Activity

72 reviews

Have you ever wished your drawings would come alive and the stick figures or objects on your paper could move around? What sounds impossible actually is not! In this activity, you will make your drawing move around by letting it float on water. What makes this possible is the interesting chemistry of dry erase markers. These markers are usually used to write on white boards or glass surfaces and can easily be erased to make space for more writing or drawing. It turns out that they are also… Read more

Suck It Up! How Water Moves Through Plants

STEM Activity

118 reviews

Have you ever heard someone say, "That plant is thirsty," or, "Give that plant a drink of water"? We know that all plants need water to survive, even bouquets of cut flowers and plants living in deserts. But have you ever thought about how the water moves within the plant? In this activity, you will put carnations in dyed water to figure out where the water goes. Where do you think the dyed water will travel, and what will this tell you about how the water moves in the cut flowers? Read more

Candy Rainbow

STEM Activity

110 reviews

Here is a fun project you can try with leftover candy you have. You will make some amazing art using nothing but colored candy and hot water—and a little bit of science. Save some of your candy and get started! Read more

Make a Milk Rainbow

STEM Activity

137 reviews

Have you ever seen a rainbow after a rainfall, or drawn a rainbow for fun? They can be fun to make using colorful markers or other craft supplies. But did you know you can actually make a simple rainbow using milk, liquid detergent (i.e., soap), and food coloring? How the rainbow is created by this mixture might surprise you! In this science activity, you will make your own milk rainbow and explore how detergent and surface tension are involved in its creation. Read more

Make a Straw Siphon

STEM Activity

68 reviews

What's an easy way to move liquid from one place to another? A siphon! With just a little effort to get it started, you can then sit back and watch liquid flow from one container to another, as it seemingly defies gravity by going uphill. Try this activity to make your own simple siphon using straws. Read more

Making Shadow Puppets

STEM Activity

86 reviews

Have you ever played with your own shadow? It is fascinating how it follows your every move. But why do you not see your shadow every day? Why is your shadow very long sometimes, and other times very short? In this activity, you will make your own shadow puppet and explore how you can change the shape or size of its shadow. If you like, you can even create your own shadow play! Read more

Explore Our Science Videos

Does Sense of Touch Impact a Cat's Behavior? | Science Project

Colorful Melting Ice Ball Patterns - STEM Activity

How To Balance Anything – STEM activity