Third Grade STEM Activities for Kids (223 results)

Fruits Gone Bad? Discover Enzymatic Browning

STEM Activity

54 reviews

Have you ever wondered why apple slices turn brown once you cut them or why a yellow banana gets dark spots over time? Both of these phenomena have the same cause: enzymatic browning triggered by an enzyme called polyphenol oxidase (PPO). In this activity you will find out how this enzyme works by turning a banana from yellow to brown in just a matter of seconds. Then you will explore how you can keep your apple slices looking fresh! Read more

Model the Rock Cycle with Crayons

STEM Activity

148 reviews

Use crayons to model the rock cycle in this fun activity! You will make colorful sedimentary, metamorphic, and igneous "rocks" from crayon shavings. Read more

Protect Your 'Eggstronaut': Build an Egg-Drop Lander

STEM Activity

170 reviews

The egg-drop project is a classic and time-honored tradition in many science classes. The goal is usually to build a device that can protect an egg when dropped from a high location. This activity puts a twist on the classic project, motivated by real-world advances in space exploration. Can you build a reusable egg-drop lander that can survive repeated falls from the same height? Try this activity and find out 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

Foaming Fake Snow

STEM Activity

139 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

Homemade Slushies

STEM Activity

109 reviews

Do you enjoy ice-cold drinks? A slushy is about as close as you can get to liquid ice: colder than water, but more drinkable than ice! Using some common household items, a little bit of patience, and the help of science, you can make this delicious, sweet drink at home. Try the activity, and you will be rewarded with a delightful treat! Read more

How Big Are the Planets in Our Solar System?

STEM Activity

149 reviews

Did you know that there are more planets than stars in our galaxy? All of these planets circle around a star, but only eight of them—Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune—circle around the Sun—the star in our solar system. This activity explores the relative size of these eight planets. Is one bigger than the others, or are they all about the same size? Read more

Make Your Own Stethoscope

STEM Activity

126 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

Paper DNA Model

STEM Activity

85 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

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

STEM Activity

49 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 Brushbot

STEM Activity

130 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

Explore Our Science Videos

Detect Litter with Machine Learning: YOLO Python Tutorial

Harvest Water from Fog Science Project

Make 3D Printed Fabric | STEM Activity