What an exciting age to be a young scientist! 3rd grade science is a fantastic time to get engaged in all kinds of science projects that explore the living world and how things work! There are so many great skills that kiddos in this age group have already been working on and will continue to develop as they explore, investigate, and discover through hands-on science experiments for 3rd graders.



So what exactly does science for 3rd graders look like and how can you encourage your kids to learn without a whole lot of effort, fancy equipment, or too difficult activities that cause confusion rather than curiosity?

Kids are naturally curious, and 3rd grade is an opportune time to introduce and practice the scientific method through fun, hands-on and easy science projects. Good science projects for 3rd graders help them ask scientific questions and make predictions, and with guidance, plan and carry out investigations to answer those questions.

Topics that 3rd graders may cover in science include:

  • Changes in motion by forces such as gravity and friction
  • Magnetism
  • Weather
  • Solids, liquids, gases and changes in states of matter
  • Plants and animals, and the relationships between them

Below you will find over 25 of the best science project ideas, covering many of these science topics and more.

Our science activities have you, the parent or teacher, in mind!  Easy to set up, quick to do, most projects will take only 15 to 30 minutes (or longer if kids want to experiment further) to complete, and are heaps of fun!  Plus, our supply lists usually contain only free or cheap materials you can source from home.


Click on the projects below for the full supply list and step-by-step instructions for each activity. Also, check out our helpful tips for putting together a 3rd grade science fair project!

Acid Rain Experiment

What happens to plants when rain is acidic? Set up an easy science project with flowers in vinegar. Get kids thinking about what causes acid rain and what can be done about it.

Air Resistance

A quick and easy way to introduce kids to independent and dependent variables. Fold some paper and compare the air resistance they have when you drop the paper from a height.

Apple Browning Experiment

How do you keep apples from turning brown? Do all apples turn brown at the same rate? Grab some apples and lemon juice and let’s find out.

Why Do Apples Turn Brown?

Art Bots

Use your engineering skills to come up with a cool pool noodle robot that can do art too!

Art Bots

Bottle Rocket

Make a rocket from a water bottle with a cool chemical reaction that is sure to send it flying! Fun chemistry kids will want to do again and again!

Coastal Erosion Model

Ever noticed what happens to the coastline when a big storm rolls through?  Set up this beach erosion activity to investigate what happens.

Coastal Erosion Experiment

Color Wheel Spinner

Can you make white light from all the different colors? Find out by making your own spinning color wheel.

Color Wheel Spinner

Crayon Rock Cycle

Explore all the stages of the rock cycle with one simple ingredient, old crayons. Kids will have a blast exploring all the stages, and they can even color with their new rock crayons if you make a few!

Crayon Rock Cycle

Chromatography (with markers)

This chromatography lab is a fun way to explore separating mixtures using everyday supplies!

Drops Of Water On A Penny

How many drops of water can you fit on a penny? The answer might surprise you! Fun and easy way to learn about the surface tension of water.

Drops Of Water On A Penny

Dry Erase Marker Experiment

Is it magic or is it science? Either way, this floating drawing experiment is sure to impress! Create a dry-erase drawing and watch it float in water.

Dry Erase Marker Experiment

Electric Cornstarch

This cornstarch experiment is a fun example of static electricity. Mix up some goop or oobleck, and watch what happens when you bring it near a charged balloon.

Electric Cornstarch


Explore the molecules in water and oil and create a tasty chemistry experiment that you can pour on your veggies too!


Engineering: Marble Run (Coaster)

Dig deep into the recycling bin and grab all the cardboard you can find to create a unique ball run or marble coaster! Explore the engineering design process along the way! Make it as small or as elaborate as you want!

Marble Roller Coaster

Food Chains

All living plants and animals need energy to live on earth. Get kids thinking about how to represent this flow of energy in a simple food chain.

Food Chain Activity

Freezing Water

Explore the freezing point of water and find out what happens when you freeze salt water. All you need are some bowls of water, and salt.

Growing Crystals

Crystals make for fascinating science! Follow our borax crystal recipe to grow crystals overnight for a cool science experiment any rock hound or science enthusiast will love!


Explore magnetism through a variety of hands-on projects perfect for middle school. Our done-for-you magnet STEM pack is filled with extra projects!

Mentos and Coke

Here’s a cool fizzing experiment the kids are sure to love! You might think there’s a chemical reaction happening, but this Mentos and coke experiment is a great example of a physical reaction.

Mentos & Coke

Click here or below to get your free science ideas pack

Mini Paddle Boat

Make a paddle boat that actually moves through the water! Explore forces in motion with this simple DIY paddle boat activity.

Paddle Boat

Penny Boat Challenge

Design a simple tin foil boat, and see how many pennies it can hold before it sinks.  How many pennies will it take to make your boat sink? Learn about the force of buoyancy while you test out your engineering skills.

Penny Boat Challenge

Popsicle Stick Catapult

What kid doesn’t love to launch stuff into the air? Build a catapult from simple materials, and turn it into a fun experiment as well. Catapults are great for learning about potential and kinetic energy, and more.

DIY popsicle stick catapult Inexpensive STEM activity
Popsicle Stick Catapult

Pumpkin Clock

Although this is classically done with a potato, you can definitely experiment with other foods that are similar and test the results.

Pumpkin Clock

Red Cabbage Ph Indicator

Learn how cabbage can be used to test liquids of varying acid levels. Depending on the pH of the liquid, the cabbage turns various shades of pink, purple, or green! It’s incredibly cool to watch, and the kids love it!

Cabbage juice science experiment and making pH indicator from red cabbage
Cabbage Experiment

Salt Water Density Experiment

What happens to an egg in salt water? Will the egg float or sink? There are so many questions to ask and predictions to make with this easy saltwater density experiment.

Salt Water Density

Slime Science Experiment

Love playing with slime? Now you can turn slime-making into a fun science experiment with these easy ideas.

Basic Slime Science Information
Slime Science Project

Spaghetti Tower Challenge

Can you build a tower out of noodles? Build the tallest spaghetti tower that can hold the weight of a jumbo marshmallow. Test out those design and engineering skills with a few simple materials.

Spaghetti Tower Challenge

Strawberry DNA Extraction

Every living thing has DNA and it is the blueprint for what makes us human. Usually, you need a microscope to see DNA up close. But with this strawberry DNA extraction, you can encourage the DNA strands to release from their cells and bind together so you can see them.

Strawberry DNA Extraction

Vinegar and Milk

Kids will be amazed by the transformation of a couple of household ingredients into a moldable, durable piece of a plastic-like substance.

Milk & Vinegar

Water Filtration

Can you purify dirty water with a water filtration system? Learn about filtration and make your own water filter.

Water Filtration



Learn about the eight science and engineering practices and how they underpin all science teaching. These skills are critical for developing future engineers, inventors, and scientists!

Also, learn about the engineering design process!


3rd grade is a great time to introduce some fantastic science words to kids. Get them started with a printable science vocabulary list. You’re definitely going to want to incorporate these simple science terms into your next science lesson!


Think like a scientist! Act like a scientist! Scientists, like you and me, are curious about the world around them. Learn about the different types of scientists and what they do to increase their understanding of their specific area of interest. Discover more about What Is A Scientist


A lot of our science activities include printable worksheets. But here are our favorite science worksheets which are perfect for extending an activity, and can be used with any experiment.

Printable Science Projects Pack

If you’re looking to grab all of our printable science projects in one convenient place plus exclusive worksheets and bonuses like a STEAM Project pack, our Science Project Pack is what you need! Over 300+ Pages!

  • 90+ classic science activities with journal pages, supply lists, set up and process, and science information. NEW! Activity-specific observation pages!
  • Best science practices posters and our original science method process folders for extra alternatives!
  • Be a Collector activities pack introduces kids to the world of making collections through the eyes of a scientist. What will they collect first?
  • Know the Words Science vocabulary pack includes flashcards, crosswords, and word searches that illuminate keywords in the experiments!
  • My science journal writing prompts explore what it means to be a scientist!!
  • Bonus STEAM Project Pack: Art meets science with doable projects!
  • Bonus Quick Grab Packs for Biology, Earth Science, Chemistry, and Physics