Third Grade STEM Activities for Kids (223 results)

Build a Mini LED Lightsaber

STEM Activity

147 reviews

Build your own mini LED lightsaber with a straw in this quick Star Wars-themed STEM activity. May the Force be with you! Read more

Making Homemade Bath Bombs

STEM Activity

95 reviews

Have you ever had a refreshing bath using a bath bomb? It can be quite the relaxing experience, especially if your bath bomb has a nice fragrance or includes some bath salts. Have you ever wondered what causes a bath bomb to become so fizzy when it touches the water in the bathtub? It is due to a chemical reaction taking place between different ingredients within the bath bomb. In this activity, you will get to make your own homemade bath bombs and explore how changing the amounts of the… Read more

Oobleck: A Recipe for a Mesmerizing Mixture

STEM Activity

171 reviews

Have you ever wondered what whipped cream, jelly, and milk have in common? Aside from all being tasty, they are also all made up of tiny particles that are dispersed, or distributed, in water. This type of mixture is called a heterogeneous mixture. Some of these have very interesting physical properties, such as acting like a solid and a liquid at the same time! In this activity, you will get to create Oobleck, a mixture that is made using cornstarch and water, and then explore these… 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

Stacking Liquids

STEM Activity

63 reviews

Did you know that not only can solid objects sink or float, but liquids can, too? It is actually possible to stack different liquids on top of each other in layers. The key is that all the different layers must have different densities. You can stack them by either picking several liquids with a range of densities, or by varying the density of one liquid by adding chemicals like sugar or salt to it. If you choose colored liquids, or add food coloring to each layer, you can even create a whole… Read more

Build A Wall Marble Run

STEM Activity

145 reviews

In this activity, you will use recyclable materials to make your own wall marble run. A marble run is a fun toy and a great way to learn about physics concepts like kinetic and potential energy. Do you think your marble will make it to the end of the track? Read more

Color-changing Cabbage Chemistry

STEM Activity

60 reviews

What if you could take a single liquid, and change it into a rainbow of colors without using food dye. You can! In this activity you will use red cabbage to make what is called an indicator solution. Indicator solutions can change colors depending on what you add to them. In this case adding something acidic (like lemon juice) will change it to one color while adding something basic (like bleach) will change it to another. Try and see how many colors you can make using different household… Read more

Dissect a Flower

STEM Activity

93 reviews

Springtime is when nature comes back to life. Trees are growing their leaves again and flowers are sprouting, displaying their beautiful colors and spreading their delightful smell. But have you ever looked at a flower in more detail? What parts do flowers consist of? Are all flowers alike? In this activity, you will find out by dissecting, or taking apart, a flower piece by piece. How many plant parts do you think you can identify? Read more

Make Marbled Cards Using Science!

STEM Activity

86 reviews

Do you like both, arts and science? Then this is the perfect activity for you! You will create beautiful marbled paper cards and practice science at the same time! The only materials you need are shaving cream, food coloring, and sheets of paper. It might get a bit messy, but that is part of the fun! Read more

Build a River Model!

STEM Activity

118 reviews

Earth is a very watery place! More than 70% of the Earth's surface is covered by water. This is due to the many water bodies that can be found everywhere on our planet. What types of water bodies do you know? They are all very distinct from one another in their appearance, size, shape, and movement. In this activity, you will explore the distinct characteristics of a river by creating a river model inside a pan with sand, pebbles, and real water! After that, you can continue to model other… Read more

Build a Rubber Band Paddle Boat

STEM Activity

56 reviews

Build your own bathtub or pool toy from simple craft materials in this fun activity! You will build a rubber-band-powered boat that can zip across the surface of the water after you wind up the rubber band. Read more

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