Third Grade STEM Activities for Kids (223 results)

Build a Brushbot

STEM Activity

120 reviews

Brushbots are a simple, fun type of robot that you can build out of arts and crafts materials. They are easy to build and you do not need any previous experience with robotics. You can build them yourself, build two robots with a friend and race them against each other, or even make them sumo wrestle! Go to the Materials section to see what parts you need to build a brushbot, and see the instructions for a step-by-step guide on how to build one. Read more

Build A Vortex Cannon!

STEM Activity

69 reviews

Here is a riddle for you: I am everywhere but you don't see me—what am I? The answer is: air! It is all around us, but it is usually invisible. We can, however, see the effect air has—for example when wind is moving tree branches. Air can move gently to create a nice breeze or turn into a wild and destructive hurricane. Not only can wind move objects with air, you can do it, too—as long as the objects are not too heavy! You can, for example blow on something—or you can… Read more

Foaming Fake Snow

STEM Activity

137 reviews

If you live where there is snow, it can be fun to play in it for a while—but it can get quite chilly! Or maybe you live in a place that does not get snow. In this fun activity, you can experience something similar to snow anytime, in the comfort of your own home. You will mix together common kitchen supplies to make a sculpted object, and then, whenever you decide, you can let your snow creation "melt" away into a white surface. Curious about how kitchen chemistry can look like snow? Try… Read more

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Make String from Algae

STEM Activity

210 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

Make Your Own Stethoscope

STEM Activity

117 reviews

Have you ever wondered what happens to the heart as we exercise intensely? How does its beating change? A doctor can figure this out by using a tool called a stethoscope, which is a long, thin plastic tube that has a small disc on one end and earpieces on the other end. In this activity, you will make a homemade stethoscope and use it to measure peoples' heart rates at rest and after exercising. Read more

3D Print with Sand: No 3D Printer Required!

STEM Activity

45 reviews

Don't have your own 3D printer? No problem! In this fun activity you will make your own colorful 3D prints using craft sand and glue. No 3D printer required! Read more

Build a Two-Stage Balloon Rocket

STEM Activity

62 reviews

If you have ever watched a rocket launch on TV, you might have noticed that rockets have multiple stages. Some parts of the rocket fall off and burn up in the atmosphere whereas the rest of the rocket keeps going. Why does this happen? Try this activity to find out and build your own two-stage rocket using balloons! Read more

Build an Archimedes Screw

STEM Activity

78 reviews

The Archimedes screw is an ancient device used to lift water from one location to another. They are so useful that they are still in widespread use today! After a quick trip to the hardware store, you can build your own Archimedes screw in this fun activity. Read more

Make a Rubber Band Guitar

STEM Activity

164 reviews

Did you know that the modern guitar is an instrument that dates back over 4,000 years? The first guitar music was published in 1546, during a time when guitars still had strings made from animal intestines! While guitars have a long history, they are still extremely popular in modern day music. Have you ever wondered how they make the music you listen to everyday? In this activity we're going to make our own guitars, and experiment with the different sounds we can create. Read more

Model Your Blood Flow

STEM Activity

63 reviews

Why is it important to eat healthy and exercise? If you don't, you might end up with a cardiovascular disease. These diseases are conditions that affect your heart and blood vessels. The job of your cardiovascular system is to transport blood through your heart, veins, and arteries, to provide oxygen and nutrients to your body. If this blood flow doesn't work properly anymore, it can have serious consequences. In this activity, you will find out what happens to the blood flow of people that… Read more

Paper DNA Model

STEM Activity

75 reviews

Ever wondered how DNA, the genetic blueprint of a life-form, can encode and pass on the information on how to grow and maintain that life-form? Just like a cookbook contains a complete recipe for a dish, DNA stores the recipe for the life of an organism. Although each human has a unique DNA sequence, the DNA in all of us is about 99.9% identical! In this activity, you will make a model for a short section of DNA—enough to get a sense of what DNA is like and how it encodes life. Read more

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