Easy Science Fair Project for 3rd Graders

Want to see your third grade science students' eyes light up? Tell them they're going to do an experiment! These activities are easy enough for any classroom or kitchen, and they're full of science concepts kids need to learn.

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1. Make glowing flowers

Flowers with their vascular systems glowing blue and green under black light

This one will make kids' eyes pop out of their head! Use highlighters and a blacklight flashlight to reveal the vascular system of flowers.

Learn more: Tamara Horne

2. Flick pennies to learn about inertia

Third grade science student flicking an index card out from underneath a stack of pennies suspended over a cup of water

This is one of those science experiments that kind of looks like magic, but it's really all about the laws of motion. It might take a little practice to get the index card flick just right, but the results are always cool!

Learn more: Frugal Fun For Boys and Girls/Penny Inertia

3. Find your way with a DIY compass

DIY compass made from a needle floating in water

Here's an old classic that never fails to impress. Magnetize a needle and float it on the water's surface, and it will always point north.

Learn more: STEAM Powered Family

4. Separate salt and pepper with static electricity

Spoon charged with static electricity separating pepper from salt

When you mix up salt and pepper, you'd think it would be almost impossible to separate them again. But using a little static electricity and a plastic spoon, it's surprisingly simple.

Learn more: Science Kiddo

5. See the temperature rise in a chemical reaction

Steel wool in vinegar in a beaker, with a thermometer (Third Grade Science)

When iron meets oxygen, rust forms. Use vinegar to remove the protective coat from steel wool and watch the temperature rise from the chemical reaction.

Learn more: 123Homeschool4Me/Thermal Reaction

6. Design a candy-delivery machine

Candy delivery machine built of drinking straws (Third Grade Science)

Learn about inclined planes with this fun simple machines project. Kids can get creative and develop any kind of delivery system they like!

Learn more: 123Homeschool4Me/Candy Machine

7. Mix up your own silly putty slime

Blob of bright pink slime sitting on clear zipper bags (Third Grade Science)

Kids adore slime, and it's actually a terrific way to teach them about polymers. This third grade science experiment plays around with different formulations to create slime with varying properties.

Learn more: Science Buddies/Slime Chemistry

8. Craft fossils from glue

Create clay molds of natural objects, then fill them with school glue to make your own "fossil" casts. This is a great project to try before a trip to the natural history museum.

Learn more: Education.com/Glue Fossils

9. Float an iceberg

Paper boat floating in a dish with a large chunk of ice

Use a balloon to make an iceberg, then float it in a dish of water to learn how much you can see above and below the waterline. Try experimenting with saltwater to see how the density changes things.

Learn more: Science Sparks/Icebergs

10. Defy gravity with magnets and paper clips

Cardboard strip supported by colorful blocks, with paper clips suspended from magnets underneath (Third Grade Science)

Magnets are always a hit in the classroom. Use this simple experiment to discover more about gravity and the effects of magnets on metal objects.

Learn more: Buggy and Buddy/Magnet Gravity

11. Take a Play-Doh core sample

Playdough colors layered, with holes punched in the top green layer

Learn about the layers of the Earth by building them out of Play-Doh, then students can take a core sample with a straw. (Love Play-Doh? Get more learning ideas here.)

Learn more: Line Upon Line Learning

12. Spin a disappearing color wheel

Spinning disk on a string, showing a beige color

Color a paper disk with the six primary and secondary colors. Then thread a string through the middle and make it spin. The colors will seem to disappear!

Learn more: Crafts Guru on YouTube

13. Crystallize some pretty fall leaves

Colorful fall leaves covered in crystals (Third Grade Science)

Every kid loves making crystals. In this third grade science project, learn about supersaturated solutions by crystallizing some colorful fall leaves. Then use them as fall classroom décor!

Learn more: Schooling Active Monkeys

14. Find a robot's center of gravity

Print out, cut, and color this free paper robot. Then glue some coins to the back and have your students try to find its center of gravity!

Learn more: Buggy and Buddy/Balancing Robot

15. Find the most waterproof roof

Third grade science student spraying water on a LEGO house with a wood roof

Calling all future engineers! Build a house from LEGO, then experiment to see what type of roof prevents water from leaking inside.

Learn more: Science Sparks/Waterproof Roof

16. Run marble races with pool noodles

Pool noodle cut in half horizontally, with cardboard finish line sign at one end

Crack open a pool noodle or two and create your own marble racetracks. Experiment with angles, force, and surface materials to find the fastest way to get the marble to the bottom. (Find more fun ways to use pool noodles in the classroom here.)

Learn more: The Techy Teacher

17. Make sun prints to display

Shadow prints of scissors and key on blue sun print paper (Third Grade Science)

You'll need special sunprint paper for this project, but it's inexpensive and easy to find. Kids learn about chemical reactions as they use the power of the sun to create unique works of art.

Learn more: Science Buddies/Sunprints

18. Make your own bouncing bubbles

Have your third grade science students put on gloves and watch the bubbles bounce! Then encourage them to experiment with their own bubble solution. Try different soaps, mixing up the ratios to make the strongest bubble possible.

19. Build a better umbrella

Cupcake wrapped balanced upside-down on wood craft sticks, with water being poured on top

Challenge students to engineer the best possible umbrella from various household supplies. Encourage them to plan, draw blueprints, and test their creations, using the scientific method.

Learn more: Raising Lifelong Learners

20. Project the stars on your ceiling

Third grade science student poking holes in the bottom of a paper cup in the shape of a constellation

Use the video lesson in the link below to teach 3rd grade science students why stars are only visible at night. Then create a DIY star projector to explore the concept hands-on.

Learn more: Mystery Science

21. Blow through a water whistle

Third grade science students blowing through a straw into a cup of water

Learn about the science of sound with this easy experiment. Kids will love building their own whistles from straws and a glass of water.

Learn more: My Baba

22. Construct a marshmallow catapult

Third grade science student playing with a catapult made of a tissue box and pencils

Fling some sweet treats in the name of science! All you need is an old tissue box, pencils, rubber bands, and a few other supplies to learn about trajectory, air resistance, gravity, and more.

Learn more: Frugal Fun for Boys and Girls/Tissue Box Catapult

23. Experiment with ice, salt, and water temperature

Two glasses of water, one with ice and a thermometer

This simple experiment requires only water, ice, salt, and a thermometer. Your third grade science class can explore how ice and salt affect the temperature, a simple but effective lesson on heat transfer and freezing points.

Learn more: 123 Homeschool For Me/Ice, Salt, and Temperature

24. Blow bubbles inside bubbles inside bubbles

Large bubble with several smaller concentric bubbles inside

If there's a more fun way to learn about surface tension than bubbles, we haven't found it yet! Create a soap solution by using dissolved sugar and discover more about elasticity and volume as you blow bubbles inside bubbles inside bubbles…

Learn more: RonyesTech

25. Experiment with colors

Coffee filter flowers dyed different colors with text reading Spring Science Flowers Chromatography Science Project

Play around with colors, mix them together, and then use a little science magic to pull them apart again. This chromatography science project requires only simple supplies, like coffee filters and markers.

Learn more: 123 Homeschool 4 Me/Chromatography

26. Understand the science behind bath bombs

Bath bombs and a glass of fizzy water (Third Grade Science)

Bath bombs certainly make bath time more fun, but what makes them work? Explore chemical reactions and get squeaky clean all at the same time!

Learn more: Learning Hypothesis

27. Use water balloons to explore buoyancy

Water balloons in a large red bucket, labeled water, salt, corn syrup, oil, and more

Fill water balloons with different solutions (oil, saltwater, plain water, etc.) and place the balloons in a large bucket of water to see if they sink or float. This is a cool project to do with your 3rd grade science class on the playground on a sunny day.

Learn more: 123 Homeschool 4 Me/Balloon Density

28. Explore static electricity with jumping goop

Orange balloon next to a spoon of white liquid being drawn to the balloon by static electricity

Your students have probably tried rubbing a balloon on their heads to create static electricity with their hair. This experiment is even cooler to see, as a mix of cornstarch and oil seems to leap off the spoon in front of their eyes!

Learn more: Frugal Fun for Boys and Girls/Static Electricity

29. DIY these natural-dye markers

Collage of photos showing third grade science student filling markers with natural ink (Third Grade Science)

This is the kind of project that turns STEM into STEAM! Learn about the process of extracting natural dyes and use paper chromatography to make your own DIY markers. Kids can use these markers to create amazing masterpieces!

Learn more: Science Buddies/DIY Markers

30. Investigate the effects of erosion

Third Grade Science Erosion Third Grade Thinkers

Compare the effects of "rain" on hills of bare soil vs. those covered with grass. Have your third grade science students predict which they think will stand up to erosion better and then test their hypotheses.

Learn more: Third Grade Thinkers/Erosion

31. Learn how water temperature affects density

Jars of water with colorful layers of water

Looking for a simple, quick, and colorful science experiment? This one just requires some mason jars, hot and cold water, and food coloring. Kids will be amazed at the results!

Learn more: Steamsational

32. Dissolve cups to learn about types of change

Collage of styrofoam cup siting in a tin and same cup dissolving

Teach your third grade science class about the differences between physical and chemical changes with this quick and easy experiment involving styrofoam cups.

Learn more: The Owl Teacher/Dissolving Cups

33. Grow bacteria from common surfaces

Collection of petri dishes growing mold, labeled fridge, hand, fish tank, and more

There's never been a better time to learn about the way germs spread! Take samples from a variety of surfaces, then watch bacteria grow in petri dishes just like grown-up scientists.

Learn more: Happiness is here

34. Take friction for a ride

Third grade science student sitting in a wood tray, pulling himself along with a rope

Your students will love pulling their way across the floor as they discover more about friction and its effects on motion. Build your own "sled" or use a pre-made box or tray.

Learn more: PorterGaudCyclones on YouTube

35. Step through an index card

Man holding an index card cut in a way that allows it to create a large opening

With carefully placed scissor cuts on an index card, you can make a loop large enough to fit a (small) human body through! Kids will be wowed as they learn about surface area.

Learn more: Mess for Less

36. Explode colorful paint bags

Sealed plastic bag filled with pink paint, swelling with air

Experiments with acids and bases are always fun for kids. You'll want to take this one outside because it's bound to make a mess. Mix colored chalk with vinegar and watch the colors fly!

Learn more: Growing a Jeweled Rose

37. Turn crayons into rocks

Collage of crayon shavings, labeled igneous, sedimentary, and metamorphic

Demonstrate the effects of heat and pressure on crayon shavings to explain the different types of rocks to students. It's a colorful intro to geology!

Learn more: The Owl Teacher/Crayon Rocks

38. Go green with recycled paper

Third grade science student pressing paper pulp into a wood photo frame

We talk a lot about recycling and sustainability these days, so show kids how it's done! Recycle old worksheets or other papers using screen and picture frames.

Learn more: Undercover Classroom

39. Filter sediment from dirty water

Child pouring dirty water into a cup propped over a jar

Explore sediments and water filtration with this easy third grade science experiment. It's a fun way to learn more about the water cycle.

Learn more: Teach Beside Me

40. Send secret messages with invisible ink

Flashlight shining on piece of paper with lines written in both regular and invisible ink (Fifth Grade Science)

Kids will love swapping secret messages with their friends in this acid-base science project. Mix the water and baking soda and use a paintbrush to write a message. Then use grape juice to expose the message or hold it up to a heat source.

Learn more: ThoughtCo

41. Teach the scientific method with milk and cookies

Glass of milk and stack of cookies sitting on a plate next to text reading Milk & Cookies and the Scientific Method

This third grade science project is sure to be a slam dunk—cookie dunk, that is! Kids experiment by dipping cookies in milk, using the scientific method to document their findings. Check out our other edible science experiments, too.

Learn more: Around the Kampfire

42. Put together a compost bottle

Compost bin built in a two liter soda bottle, with child pouring water into it

Learn about the decomposition of food and how composting can provide nutrients for growing more food with this easy earth science project.

Learn more: Busy Mommy Media

43. Sprout sweet potatoes

Sweet potato halves propped on plastic cup limbs by toothpicks

Potatoes grow from tuberous roots, and under the right conditions, new shoots appear from those roots. This third grade science experiment explores the biological science behind cloning.

Learn more: Science Buddies/Sweet Potatoes

44. Stab a straw through a potato

Man's hand stabbing a sweet potato with a drinking straw

Plastic straws may seem flimsy, but by using the power of air pressure, you can make one strong enough to stab all the way through a potato!

Learn more: KiwiCo

45. Shake up some ice cream

Third Grade Science Ice Cream More Than a Worksheet

Get kids up and moving when they shake their way to ice cream, made from scratch using ice and plastic zipper bags! Talk about heating and cooling as well as condensation while you enjoy your snack.

Learn more: Mom of 6

Keep up the STEM enthusiasm with these fun and engaging third grade math games.

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45 Fun Third Grade Science Activities Anyone Can Do

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