Exciting and Easy 3rd Grade Science Fair Projects for Kids

Getting involved in 3rd grade science fair projects is a powerful way to nurture curiosity and critical thinking in young learners. With hands-on activities ranging from growing plants to building simple machines, students gain a deeper understanding of science through real exploration.

This guide offers classroom-friendly, exciting science fair ideas that are easy to set up, fun to run, and rich in learning. Let’s dive into projects your students will love!

Biology 3rd Grade Science Fair Projects

Biology gives kids a chance to study living things—from plants to their own senses! These projects are simple, visual, and full of discovery.

1. Do Plants Grow Better With More Light?

Objective: Determine how varying light conditions affect plant growth.

Do plants grow better with more light?

Materials:

• Three small potted plants of the same species
• Measuring tape​
• Notebook for observations​

Procedure:

• Place each plant in a different light condition: direct sunlight, partial sunlight, and low light.​
• Water the plants equally and observe their growth over two weeks.​
• Measure and record the height of each plant every two days.​

Learning Outcome: Plants exposed to more light should exhibit more growth compared to those in low-light conditions.

2. Exploring the Five Senses

Objective: Test how well our senses help us identify the world.

Exploring the five senses experiment

Materials:

• Various objects with distinct textures, smells, and tastes​
• Blindfold​
• Notebook for observations​

Procedure:

• Blindfold the participant.​
• Present different objects for them to feel, smell, or taste.​
• Ask them to identify the objects based on the sense being tested.​
• Record their responses and discuss the findings.

Learning Outcome: Students will gain insight into how sensory information is processed and the reliance on multiple senses for accurate perception.

3. Investigating Mold Growth on Bread

Objective: See what conditions help mold grow.

Investigating mold growth on bread

Materials:

• Slices of bread​
• Seal-able plastic bags​
• Water​
• Notebook for observations​

Procedure:

• Lightly moisten a slice of bread and place it in a plastic bag.
• Seal the bag and store it in a warm, dark place.​
• Observe and record mold growth daily.​
• Compare with a dry slice of bread stored under similar conditions.​

Learning Outcome: Students will learn about fungal growth and the factors that influence it.

Simple Physics and Engineering Projects

Physics and engineering projects introduce students to fundamental principles through interactive experiments.

1. Building a Balloon-Powered Car

Objective: Demonstrate Newton’s Third Law of Motion using a balloon rocket.

Building a balloon-powered car experiment

Materials:

• Small plastic bottle​
• Straws
• Bottle caps​
• Balloon​
• Tape​
• Skewers​

Procedure:

• Construct a simple car using the bottle as the body and bottle caps as wheels.​
• Attach a balloon to the rear of the car, ensuring it can inflate and deflate freely.​
• Blow up the balloon and release it, propelling the car forward.​
• Observe the distance traveled and discuss the forces at play.​

Learning Outcome: Students will understand action and reaction forces and how they influence motion.

2. Creating a Simple Circuit

Objective: Learn the basics of electrical circuits.

Creating a simple circuit experiment

Materials:

• Battery​
• Light bulb
• Wires
• Switch

Procedure:

• Connect the battery, light bulb, and switch using the wires to form a complete circuit.
• Test the switch to see if it turns the light bulb on and off.
• Try different setups—like using two batteries—to see how the brightness changes.

Learning Outcome: Students will grasp how electricity flows in a circuit and how components like switches control power.

3. Paper Bridge Challenge

Objective: Understand engineering principles related to weight distribution and design.

Paper bridge challenge

Materials:

• Sheets of paper
• Books or blocks (to support ends)
• Small weights (coins, washers)

Procedure:

• Create bridges using different paper folds (flat, accordion, triangular beams).
• Place the bridge between two supports.
• Add weights gradually and observe when the bridge collapses.
• Compare different designs for strength.

Learning Outcome: Students explore how structure affects strength, laying groundwork for civil engineering concepts.

Chemistry Science Fair Projects for 3rd Grade

Chemistry is all about fun reactions! These experiments are safe, visual, and sure to wow your 3rd graders.

1. Making a Homemade Volcano

Objective: Observe a chemical reaction that mimics a volcanic eruption.

Make a homemade volcano experiment

Materials:

• Baking soda
• Vinegar
• Dish soap
• Food coloring
• A small bottle
• Tray or large dish

Procedure:

• Place the bottle on the tray and fill it halfway with vinegar.
• Add a few drops of dish soap and food coloring.
• Add two tablespoons of baking soda and watch the eruption!

Learning Outcome: The mixture will bubble and foam over, mimicking lava as carbon dioxide gas is released from the reaction between vinegar (acid) and baking soda (base).

2. Magic Milk Experiment

Objective: Explore surface tension and chemical interaction.

Magic milk experiment

Materials:

• Whole milk
• Food coloring
• Dish soap
• Cotton swabs
• Shallow plate

Procedure:

• Pour milk into a plate and add drops of food coloring.
• Dip a swab in dish soap and touch the milk surface.
• Watch colors swirl and move!

Learning Outcome: Kids learn how soap breaks surface tension and how molecules interact.

3. Making Invisible Ink with Lemon Juice

Objective: Discover how heat reveals hidden writing.

Making invisible ink with lemon juice

Materials:

• Lemon juice
• Cotton swab or paintbrush
• White paper
• Heat source (lamp or iron)

Procedure:

• Dip the swab in lemon juice and write a message on the paper.
• Let it dry completely.
• Hold the paper near a heat source to reveal the hidden writing.

Learning Outcome: The message will slowly appear in brown as the heat oxidizes the lemon juice.

Environmental Projects for 3rd Grade

These projects show kids how science applies to the planet they live on and how they can help protect it.

1. Water Filtration Model

Objective: Show how dirty water can be cleaned using simple materials.

Water filtration model

Materials:

• 2-liter bottle (cut in half)
• Gravel, sand, cotton balls, coffee filter
• Dirty water (muddy water)
• Container to catch filtered water

Procedure:

• Invert the top half of the bottle into the bottom.
• Layer cotton balls, coffee filter, sand, and gravel inside.
• Pour dirty water through the top and watch it filter.

Learning Outcome: Cleaner water drips through, showing how natural filtration works.

2. What Decomposes Fastest?

Objective: Investigate decomposition rates of various materials.

What decomposes fastest?

Materials:

• Banana peel, plastic bag, paper, leaves
• Clear containers with lids
• Soil

Procedure:

• Fill containers with soil and place one material in each.
• Seal and leave in a warm spot for 2–3 weeks.
• Check which materials break down the fastest.

Learning Outcome: Organic materials like leaves and banana peels decompose quickly; plastic remains unchanged.

3. Solar Oven S’mores

Objective: Learn how sunlight can be used as energy.

Solar oven S’mores experiment

Materials:

• Pizza box
• Aluminum foil, black paper, plastic wrap
• Graham crackers, marshmallows, chocolate

Procedure:

• Line the inside of the pizza box with black paper.
• Cover the lid with foil and create a clear plastic window.
• Assemble s’mores inside and place them under the sun.

Learning Outcome: The sun’s heat melts the chocolate and marshmallow—delicious science!

Tips to Help Students Succeed at the Science Fair

Science fairs are about more than just cool experiments—they’re a chance to build confidence and communication skills. Here are some ways teachers can support student success:

Science fair tips for students

1. Choose Projects Based on Student Interests

Whether it’s plants, explosions, or building things—choose a project kids will love. Enthusiasm leads to deeper engagement.

2. Encourage the Scientific Method

Teach students to ask a question, form a hypothesis, conduct an experiment, and analyze results. Even simple experiments can use this structure.

3. Use a Visual Display Board

Let kids organize their project on a tri-fold board: include the problem, hypothesis, procedure, results, and conclusion. Photos and charts make it fun and clear!

4. Practice Presenting

Encourage kids to explain their project to classmates or parents. It builds confidence and deepens understanding.

5. Keep It Safe and Age-Appropriate

Ensure all experiments use safe materials and require minimal adult supervision. Always supervise heat or sharp objects.

6. Highlight Creativity

Let students personalize their display with colorful visuals, drawings, and even costumes to match the theme of their experiment.

Frequently Asked Questions

1. What science topics are in third grade?

Third-grade science often includes earth science (weather, planets), life science (plants, animals, ecosystems), physical science (force, motion, matter), and environmental science. These broad topics allow for a wide range of science fair projects that align with the curriculum.

2. How to do an elementary school science fair project?

Start by explaining each step clearly. Help them form a hypothesis, encourage them to conduct experiments, and assist in documenting observations accurately.

3. What are the topics for science in grade 3?

Key third-grade topics include:

• Forces and motion
• Plant life cycles
• Animal habitats
• Earth processes (volcanoes, erosion)
• Simple machines
• Weather and climate

These provide the foundation for many fun and educational science projects.

4. What are the top 10 science fair projects for 3rd grade?

While many projects are great, here are 10 favorites:

• Plant growth under different lights
• Moldy bread experiment
• Balloon-powered car
• Magic milk
• Baking soda volcano
• Crystal growing
• Water filter
• Compost jar
• Solar oven
• Paper bridge challenge

These combine educational value with wow-factor fun!

Final Thoughts

Science fairs are a fantastic way to nurture curiosity and confidence in 3rd grade. These projects encourage hands-on learning, help kids apply the scientific method, and make science fun and memorable. Whether your child loves nature, explosions, or simple experiments, there’s something exciting for every interest and skill level. We hope these 3rd grade science fair projects spark new ideas and inspire young learners to explore the world around them.

Want printable worksheets to support every step? Check out Worksheetzone for engaging resources to extend the learning and make science even more fun!