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Science Buddies' third grade science projects are the perfect way for third grade students to have fun exploring science, technology, engineering, and math (STEM). Our third grade projects are written and tested by scientists and are specifically created for use by students in the third grade. Students can choose to follow the science experiment as written or put their own spin on the project.

For a personalized list of science projects, third graders can use the Science Buddies Topic Selection Wizard. The wizard asks students to respond to a series of simple statements and then uses their answers to recommend age-appropriate projects that fit their interests.

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Science Fair Project Idea
Do you think you could build a car powered by nothing but air? A balloon-powered car is pushed forward by air escaping from a balloon, and it is fun and easy to build with materials you already have around your house. Can you imagine how you would want your own balloon-powered car to look? Can you design a car that will travel as far as possible? You can even measure your car's speed using your smartphone and a special sensor app. Get ready to grab some simple supplies to bring your idea to… Read more
Science Fair Project Idea
Some objects float on top of the ocean, and other objects sink to the bottom. Why? Try this eggsperiment to find out! Read more
Science Fair Project Idea
Try your hand at this engineering challenge. Can you build a "launcher" device to launch a ball as far as possible and a "receiver" to catch it? Building a receiver provides an extra twist to a traditional catapult project. Add to the challenge by using a limited set of materials to build your machine and calculate a score based on your throw distance and materials used. Read more
Science Fair Project Idea
Does green apple juice taste the same as red apple juice? That might seem like a silly question. Food coloring does not have any flavor—so how could it change how something tastes? Find out whether it does in this food science project! Read more
Science Fair Project Idea
"Plastic made from milk" —that certainly sounds like something made-up. If you agree, you may be surprised to learn that in the early 20th century, milk was used to make many different plastic ornaments —including jewelry for Queen Mary of England! In this chemistry science project, you can figure out the best recipe to make your own milk plastic (usually called casein plastic) and use it to make beads, ornaments, or other items. Read more
Science Fair Project Idea
In this engineering challenge, you will build a ball run from paper and tape, but there's a twist! You want to make your ball run as slow as possible. How long can you make it take for the ball to get from the entrance to the exit? Follow the contest rules to try it out and enter the 2022 Fluor Engineering Challenge! Read more
Science Fair Project Idea
Imagine telling your friends about your latest science project: using a battery to make a light turn on. You might get some blank stares...sounds a little boring and basic, right? Now tell them you will do it with a potato! Yes, you can actually use fruits and vegetables as part of an electric power source! Batteries power many things around you, including cell phones, wireless video game controllers, and smoke detectors. In this science project, you will learn about the basics of battery… Read more
Science Fair Project Idea
Have you ever suffered from poor Wi-Fi reception for your smartphone, tablet, or laptop? Certain materials can actually block a Wi-Fi signal; do you think that could be part of your problem? In this science project, you will do an experiment to find out which materials cause the biggest drop in signal strength from a wireless router. Read more
Science Fair Project Idea
Where do you get your best ideas? At school with your friends? When you are out for a bike ride? Over 2,200 years ago, a scientist named Archimedes got one of his best ideas when he sat down in his bath. Eureka! He went running through the streets without even bothering with his clothes. What was he so excited about? He had discovered that when objects, like his body, are placed in water, water is pushed out of the way. Have you noticed that, too? The weight of the water that is pushed out of… Read more
Science Fair Project Idea
What do plants need to grow? Most of us would answer that they need light, air, water, and soil. But by using a process called hydroponics, you can grow plants without soil! How does it work? Try this project and see for yourself! Read more
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Free science fair projects.