Third Grade Science Projects (114 results)

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.

Let us help you find a science project that fits your interests, with our Topic Selection Wizard.

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Balloon-Powered Car Challenge

Science Fair Project Idea

Engineering Design Process

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

Baking Soda and Vinegar Rockets

Science Fair Project Idea

Scientific Method

Watching a spacecraft launch is an amazing experience. It is thrilling to see it lift off and escape Earth's gravity. Did you know that it takes a chemical reaction to get a spacecraft into space? Every time you see a one blast off, you are watching chemistry at work. In this chemistry science fair project, you will also get to blast an object into the air. You will not be using the same fuel that NASA uses for the rockets that launch their spacecrafts; instead, you will use two simple… Read more

Mixing Light to Make Colors

Science Fair Project Idea

Scientific Method

You know how to make new colors by mixing paint or crayons. For example, you get green by mixing yellow and blue, or orange by mixing red and yellow. With paint, blue, yellow, and red are primary colors, which you can use to make other colors. Have you ever tried making colors with light? Are the primary colors the same ones you use for paint? Do this experiment and find out. Read more

Ball Launcher Challenge

Science Fair Project Idea

Engineering Design Process

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

Rubber Band Car Challenge

Science Fair Project Idea

Engineering Design Process

In this engineering challenge, you will build a car powered by nothing but a rubber band. The farther the car goes, and the fewer materials you use to build it, the higher your score. The 2024 Science Buddies Engineering Challenge is over, but you can check out this page to see our other past engineering challenges and what this year's challenge will be! Teachers, lesson plan versions of this challenge are also available. Read more

Big Pieces or Small Pieces: Which React Faster?

Science Fair Project Idea

Scientific Method

Some chemical reactions occur explosively fast, others may occur almost imperceptibly s-l-o-w-l-y. This project explores what effect the particle size of the reactants has on the speed of a chemical reaction: production of carbon dioxide gas by an Alka-Seltzer® tablet. Read more

Fighting the Flu: How Your Immune System Uses Its Memory

Science Fair Project Idea

Scientific Method

Being sick is no fun, especially when your friends are doing exciting activities that you have to miss out on. Thankfully, common illnesses usually last for just a few days, and then you start to feel better. Why is this? It is thanks to the immune system, which is a group of special organs and cells in your body that constantly work to keep you healthy. In this science project, you will make a simple model to investigate how the immune system defends the human body from common illnesses, and… Read more

Build a Simple Walking Robot

Science Fair Project Idea

Engineering Design Process

Humans are pretty good at building vehicles with wheels, but building machines with legs that walk like us is a lot harder! In this engineering project you will build a simple robot that walks using a single motor. How fast can you make your robot go? Read more

Making A Candy Waterfall: Can Solids Flow Like Liquids?

Science Fair Project Idea

Scientific Method

What do sand, Skittles, and cereal have in common? They are all granular materials, which means they are made up of solid particles, but they can actually flow like liquid! Imagine pouring the sand out of a bucket or pouring the cereal out of a box— a lot like pouring water, right? In this physics science project, you will investigate how the size of granular materials affect how they flow. Read more

Make a Robot Hand Using Drinking Straws

Science Fair Project Idea

Scientific Method

Imagine how cool it would be to build a robot hand that could grasp a ball or pick up a toy. In this robotics engineering project, you will learn how to use drinking straws, sewing thread, and a little glue to make a remarkably lifelike and useful robot hand. What will you design your robot hand to do? Pick up a can? Move around a ping pong ball? It is up to you! With these starting instructions, you can design any type of hand. You will simulate human finger anatomy as the basis for a… Read more

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