Third Grade STEM Activities for Kids (223 results)

Build a Gumdrop Geodesic Dome

STEM Activity

89 reviews

Have you ever seen a geodesic dome? Geodesic domes are approximately sphere-like structures made up of interconnected triangles. A famous geodesic dome is Spaceship Earth at EPCOT in Walt Disney World, Florida, but geodesic domes are also commonly found as climbing domes at playgrounds. In this science activity, you will get to build a simple geodesic dome using gumdrops and toothpicks. Once it is built, you may be surprised by how strong it is! Get ready to do some tasty engineering! Read more

DIY Mini Propeller Car

STEM Activity

85 reviews

Build your own mini propeller car with craft materials and a simple circuit in this fun STEM activity! Read more

How Do Melting Polar Ice Caps Affect Sea Levels?

STEM Activity

81 reviews

Have you ever noticed that if you leave an ice cube out on the kitchen counter and come back to check on it in a while, you find a puddle? The same thing happens to ice in nature — if the temperature gets warm enough, the ice melts. In this science activity, you will explore what happens to sea levels if the ice at the North Pole melts, or if the ice at the South Pole melts. Does melting ice at either cap contribute to a rise in sea levels? It is an especially important question for… 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 a Homemade Compass

STEM Activity

93 reviews

Have you ever used a compass to help you figure out what direction to go? What about while on a camping trip — have you ever needed a compass to help you navigate your way through a forest? Magnetic compasses work based on Earth's magnetic field. In this science activity, you will get to make your own magnetic compass out of a sewing needle, piece of cork, and cup of water. How well do you think it will work? Get ready to find out! Read more

Balloon Magic with Bernoulli's Principle

STEM Activity

38 reviews

Have you ever seen pictures or videos of a roof being blown off a house during a hurricane or tornado? You might be surprised to hear that the roof is actually not pushed off by the strong winds but instead by the air inside the house! This can be explained by Bernoulli's principle, which states that fast-moving fluids or air, such as strong winds, have lower pressure than slow-moving air. In this activity you will demonstrate how balloons can be moved in a similar way. It is not quite as… Read more

Build a Bird Feeder to Study Birds

STEM Activity

43 reviews

Did you know that there are about 10,000 different types of birds in the world? You don't have to go far to see some of them. Birds live outside in backyards and parks and can even be found in a busy city! Do you know what kinds of birds live in your neighborhood? Have you ever taken a close look at the birds you see in your backyard to identify them and observe their behavior? In this activity, you will build a bird feeder to attract birds, so you can study them. Read more

Candy Core Samples

STEM Activity

46 reviews

Act like a geologist in this fun activity as you drill "core samples" from candy bars using a straw. Can you identify the type of candy bar just from a sample? Try this activity to find out! Read more

Do-Re-Mi with Straws

STEM Activity

37 reviews

Have you ever wondered how a musical instrument produces the beautiful sounds that it does? To make a certain note, the instrument has to make a certain sound wave. Depending on the instrument, the sound wave that is made can be affected by changing the length of part of the instrument, such as the strings in a piano or on a guitar, or a trombone’s air column. In this science activity, you will make your own musical instruments using drinking straws and explore how changing the length of the… Read more

Flying Helicopters on Mars

STEM Activity

64 reviews

During the Mars 2020 mission, NASA plans to explore the surface of Mars using a rover in combination with a lightweight helicopter. To be able to fly on Mars, this helicopter must be super light and have very efficient blades. If not, it will never generate enough lift to get off the ground. In this activity, you will make your own paper helicopter and test different blade designs. Will your findings be reflected in NASA's design? Try it out and see for yourself! Read more

How Fish Sink and Float

STEM Activity

61 reviews

Have you ever thought about why most fish never sink to the bottom of the ocean or float to the water's surface? How is it that they can stay so perfectly buoyant under water? You might be surprised to hear that most bony fish have a special organ to help them with that: a swim bladder. The swim bladder is a thin-walled sac located inside the body of the fish that is usually filled with gas. Besides helping the fish stay buoyant, it can also function as a sound producer and receptor or as an… Read more

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