Nothing engages kids in science more than hands-on activities! Important concepts are much easier to understand when you see them in action. These 3rd grade science activities are fun in the classroom or at home, and also make neat science fair projects for kids to explore on their own.

1. Take a Play-Doh core sample.

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

2. Make sun prints to display.

Third Grade Science Sunprints Science Buddies

You’ll need special 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

3. Project the stars on your ceiling.

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

4. Defy gravity with magnets and paper clips.

Third Grade Science Gravity Buggy and Buddy

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

5. Craft fossils from glue.

Third Grade Science Fossils Education

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:

6. Use water balloons to explore buoyancy.

3rd Grade Science Buoyancy Balloons 123 Homeschool 4 Me

Fill water balloons with different solutions (oil, salt water, 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

7. Explore static electricity with jumping goop.

Your students have probably tried rubbing a balloon on their head 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

8. DIY these natural-dye markers.

Third Grade Science Markers Science Buddies

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

9. Make your own bouncing bubbles. 

Have your 3rd 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. 

10. Crystallize some pretty fall leaves.

Third Grade Science Crystals Schooling a Monkey

Every kid loves making crystals. In this 3rd grade science project, learn about supersaturated solutions by crystallizing some colorful fall leaves. Then use them as fall classroom decor!

Learn more: Schooling Active Monkeys

11. 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

12. Build a better umbrella.

Third Grade Science Umbrellas Raising Lifelong Learners

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

13. 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 3rd grade science students predict which they think will stand up to erosion better and then test their hypotheses.

Learn more: Third Grade Thinkers

14. Teach the scientific method with milk and cookies.

Third Grade Science Scientific Method Around the Kampfire

This 3rd 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. 

Learn more: Around the Kampfire

15. Blow through a water whistle.

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

16. Construct a marshmallow catapult.

Third Grade Science Catapult Frugal Fun

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

17. Experiment with ice, salt, and water temperature.

3rd Grade Science Ice Salt Water 123Homeschool for Me

This simple experiment requires only water, ice, salt, and a thermometer. Your 3rd 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

18. Mix up your own silly putty slime.

Third Grade Science Silly Putty Science Buddies

Kids adore slime, and it’s actually a terrific way to teach them about polymers. This 3rd grade science experiment plays around with different formulations to create slime with varying properties.

Learn more: Science Buddies

19. Run marble races with pool noodles.

3rd Grade Science Gravity Techy Teacher

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

20. Put together a compost bottle.

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

21. Experiment with colors.

Third Grade Science Chromatography 123 Homeschool 4 Me

Play around with colors, mix them together, and then using 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

22. Blow bubbles inside bubbles inside bubbles.

Third Grade Science Bubbles Steve Spangler

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: Steve Spangler Science

23. Understand the science behind bath bombs. 

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 

24. Sprout sweet potatoes.

Third Grade Science Sweet Potatoes Science Buddies

Potatoes grow from tuberous roots, and under the right conditions, new shoots appear from those roots. This 3rd grade science experiment explores the biological science behind cloning.

Learn more: Science Buddies

25. Explode colorful paint bags.

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

26. Turn crayons into rocks.

Third Grade Science Crayon Rocks The Owl Teacher

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

27. Go green with recycled paper.

3rd Grade Science Paper Undercover Classroom

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

28. Learn how water temperature affects density. 

 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: Schooling a Monkey 

29. Dissolve cups to learn about types of change.

Teach your 3rd 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

30. Grow bacteria from common surfaces. 

Germs are gross, but also fascinating! Take samples from a variety of surfaces, then watch bacteria grow in petri dishes just like grown-up scientists. 

Learn more: Happiness is here

31. Take friction for a ride.

Third Grade Science Friction PorterGaudCyclones

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

32. Step through an index card.

Third Grade Science Surface Area Steve Spangler

This is one science experiment that never fails to amaze. 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: Steve Spangler Science

33. Filter sediment from dirty water.

Third Grade Science Filtration Teach Beside Me

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

34. Send secret messages with invisible ink.

3rd Grade Science Invisible Ink Steve Spangler

This simple experiment never fails to amaze. Have kids write messages with a paintbrush dipped in lemon juice, then hold the paper over a heat source and watch the invisible become visible as oxidation goes to work.

Learn more: Steve Spangler Science

35. 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: More Than a Worksheet

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

Looking for more science? Find experiments and projects for every grade K-8 here.

35 Hands-On Third Grade Science Activities