Third Grade STEM Activities for Kids (223 results)

Make Your Own Harmonica!

STEM Activity

300 reviews

Can you name the bestselling musical instrument in the world? If you said harmonica, you are right! The harmonica was said to be patented in 1821 by Christian Buschmann, a 16-year-old German boy. Since then, it has become the top-selling instrument in the world and a household item in many places. Luckily, creating beautiful noise is not just an art—it is also a science! In this activity, you will design and explore your own harmonica-like instrument made from household items. Time to… Read more

Build a Bristlebot, a Tiny Toothbrush Robot

STEM Activity

179 reviews

Do you think you could build a robot on the head of a toothbrush? Bristlebots are simple, tiny robots that buzz around like bugs. They are easy to build and fun to play with, and you do not need any previous experience with robotics to make one. You can even build two bristlebots and race them against each other! Move on to the Materials section to see what parts you need to build bristlebots, and the instructions for step-by-step directions on how to build them. Read more

Generate Electricity with a Lemon Battery

STEM Activity

258 reviews

Can you imagine how your life would change if batteries did not exist? If it were not for this handy storage of electrical energy, the radio in a car would not function, nor would the lights. A pacemaker or hearing device would need to be plugged into a wall outlet in order to function, and do not forget all portable electronic devices like phones, digital music players, or tablets, which are all powered by batteries. With all the frustration you might have endured coping with dead batteries,… Read more

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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

Grow Rock Candy Crystals

STEM Activity

202 reviews

Did you know you can grow your own lollipop? In this activity, you'll learn how to grow your very own rock candy. It is an easy process and not labor-intensive. So, what are you waiting for? See how large you can grow your sugar crystals before temptation takes over. Read more

Measure Up with a Homemade Thermometer

STEM Activity

252 reviews

Are you eager to understand how everyday items work, or interested in making useful objects and instruments yourself? Have you ever imagined you could build your own thermometer? In this activity, you will make a liquid thermometer to track how temperatures vary with location, indoors or outdoors. What will turn out to be the hottest spot in your home? What about the coolest? Your very own homemade thermometer will be able to tell you! Read more

Launching Homemade Baking Soda Rockets

STEM Activity

129 reviews

Have you ever enjoyed watching something lift off into the air, like fireworks at a show or a spacecraft launching? It can be an amazing experience. It is thrilling to see something lift off against Earth's gravity. To launch a spacecraft, its rockets give it a strong push that is due to a chemical reaction. This means that every time you see a spacecraft launch, you are watching chemistry at work. In this activity you will get to blast an object into the air using two simple… Read more

How Do We Breathe?

STEM Activity

176 reviews

We breathe a lot—roughly 12 to 16 times a minute for adults and even more for children! Have you ever wondered how the process of breathing works so smoothly? Our lungs allow us to inhale the oxygen our body needs, but they do much, much more. They also allow us to get rid of carbon dioxide, the waste product created in the body, and they play a vital role in singing, shouting and even giggling. In this activity you will make a model of a lung and use it to discover how air flows in… Read more

How to Make a Homopolar Motor

STEM Activity

230 reviews

What do you need to make a motor? Not much! In this quick activity, you will make a simple motor using nothing but a battery, magnet, and a piece of wire. Read more

Junkbots: Robots from Recycled Materials

STEM Activity

306 reviews

Building "junkbots" is a fun activity where you can turn recycled materials—like plastic bottles and cardboard tubes—into robots! This is a great activity for a classroom or a group of friends, because you can race your robots against each other and even make them sumo wrestle. You do not need any previous experience with robotics to build junkbots. A Science Buddies kit is available with all the electronic parts you need, including motors, batteries, and clear instructions for how… Read more

Popsicle Stick Chain Reaction

STEM Activity

142 reviews

If you enjoy chain reactions and spectacular sights, this activity is for you! Who knew weaving unspectacular tongue depressors could set off a chain reaction of sticks flying in the air? Try it out and see for yourself! Read more

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