Third Grade Science Experiments (Page 3)

STEM Activity

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Have you ever wanted to send your friend a secret message that no-one else can read? Then you might know of invisible ink—a special type of ink that you can use for writing and that does not show up on paper. Only after a special treatment will it appear again magically, and the message can be read. How does this work? Find out in this activity and write your own secret messages! Read more

Build a Floating Maglev Train

Science Fair Project Idea

Scientific Method

How can you make a train without wheels? By using magnets! In this project you will build a magnetic levitation ("maglev" for short) train that floats above a magnetic track. How much weight can you add to the train before it sinks down and touches the track? 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

Build a Popsicle Stick Catapult

STEM Activity

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Catapults were mighty handy for pirates in the golden age of piracy (during the 17th century). And medieval knights used them centuries earlier for taking down massive castle walls. Even Greeks and Romans used catapults about 2,000 years ago! These simple machines are quite handy, as long as you know how to aim them! In this science activity you will try your hand at catapult technology. Can you predict where your cotton ball will land? Read more

How Far Will It Fly? Build & Test Paper Planes with Different Drag

Science Fair Project Idea

Scientific Method

Just one sheet of paper can lead to a whole lot of fun. How? Paper planes! All you have to know is how to fold and you can have a simple plane in a matter of minutes! But what design should you use to build the best plane? In this aerodynamics science project, you will change the basic design of a paper plane and see how this affects its flight. Specifically, you will increase how much drag the plane experiences and see if this changes how far the paper plane flies. There is a lot of cool… Read more

Crime Scene Chemistry—The Cool Blue Light of Luminol

Science Fair Project Idea

Scientific Method

You may have seen police investigators on TV spraying a crime scene with a liquid that glows blue if there is any blood present. Luminol is the chemical which causes the glowing. In this chemistry science fair project, you will investigate what factors make this interesting molecule "light up." Read more

Chemistry of Ice-Cream Making: Lowering the Freezing Point of Water

Science Fair Project Idea

Scientific Method

Have you ever made your own ice cream? If you have, you probably know that you need to get the ice cream mixture really cold to freeze it quickly. Ice cubes alone will not do the job, but if you add chemicals, such as salt or sugar, to the ice cubes that surround the ice cream container, the mixture gets cold enough to freeze. Why does that work? How does adding salt or sugar affect the freezing point of water? Find out with this ice-cold science project and use your results to make your own… Read more

Archimedes Squeeze: At What Diameter Does an Aluminum Boat Sink?

Science Fair Project Idea

Scientific Method

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

Investigate the Kinetics of the Color Changing Iodine Clock Reaction

Science Fair Project Idea

Scientific Method

The iodine clock reaction is a favorite demonstration reaction in chemistry classes that usually requires toxic or hazardous chemicals. During the reaction, two clear liquids are mixed, resulting in another clear liquid. After some time, the solution suddenly turns dark blue. The reaction is called a clock reaction because the amount of time that elapses before the solution turns blue depends on the concentrations of the starting chemicals. In this green chemistry project, you will use a… 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

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