Fun and Easy Science Project Ideas for 3rd Graders

Looking for the best 3rd grade science ideas that go beyond baking soda volcanoes? Whether it’s a cool science trick with slime, a bubbly chemistry experiment with homemade toothpaste, or a sprout growing challenge in an earth science setup, there’s a cool project for every curious mind. These 3rd grade science fair projects are fun, accessible, and rooted in the scientific method, helping elementary students think critically while having a blast.

From launching a paper airplane to mixing cornstarch into a bouncy solid, each 3rd grade science project below is designed to excite and engage. Every science fair project comes with a clear goal, easy materials, and optional printable worksheets—perfect for home or classroom use.

Whether you’re guiding your child through a last-minute easy science fair project or planning ahead with standout science fair project ideas, these hands-on activities will make learning stick.

Hands-On Science for 3rd Graders Using Simple Materials

Hands-on experiments encourage problem-solving and critical thinking in young learners. These activities require minimal preparation and use of items commonly found at home.

Everyday Items for 3rd Grade Science Experiments at Home

Many exciting science experiments can be performed using everyday household materials, making it easy for kids to explore scientific concepts. Baking soda is commonly used in volcano reactions and balloon inflation experiments. Vinegar plays a key role in acid-base reactions and is also useful for cleaning-related experiments. Food coloring helps demonstrate diffusion and is often used in chromatography activities. Dish soap is great for testing surface tension, as seen in the magic milk experiment. Eggs can be used to explore buoyancy and osmosis, showing how different liquids affect their floating ability.

How Simple Materials Make Learning Fun

Using everyday items makes science accessible and engaging. Kids can explore how substances interact, test hypotheses, and observe real-time results. Interactive learning helps them retain concepts better than reading about them in textbooks.

Buoyancy Science Project for 3rd Graders with Floating Egg Experiment

Buoyancy explains why some objects float while others sink. This simple experiment with an egg and saltwater demonstrates how density affects floating.

How to Make an Egg Float in Water 🥚💦

📌 What You Need:

• 1 raw egg
• 1 tall glass
• Water
• Salt (about 6 tablespoons)

📌 Steps:

1. Fill the glass with water and place the egg inside. Observe how it sinks.
2. Remove the egg and gradually add salt to the water, stirring until it dissolves.
3. Place the egg back into the glass—this time, it floats!

Why Saltwater Changes Density

Adding salt increases water density, making it denser than the egg. This allows the egg to float. This experiment helps kids visualize the concept of density and how different liquids impact buoyancy.

 

Chemical Reaction Science for 3rd Graders with Baking Soda Volcano

Chemical reactions occur when substances interact to create new materials. This volcano project demonstrates an acid-base reaction using common kitchen ingredients.

Erupting a Mini Volcano with Baking Soda and Vinegar 🌋

📌 What You Need:

• Baking soda
• Vinegar
• Dish soap (optional, for extra foam)
• Red food coloring (optional)
• Small container (like a cup or bottle)

📌 Steps:

1. Place baking soda into the container.
2. Add a few drops of red food coloring and dish soap (for a more dramatic eruption).
3. Pour vinegar over the baking soda and watch the reaction!

What happens when you added the vinegar into the plastic bottle with baking soda and dishwashing liquid?

Baking soda (a base) reacts with vinegar (an acid) to produce carbon dioxide gas. The gas creates bubbles, causing the foamy eruption. This experiment introduces the basics of chemical reactions and gas formation in an engaging way.

Surface Tension Science for 3rd Graders with Magic Milk Experiment

The magic milk experiment is a simple yet fascinating way for 3rd graders to explore surface tension and chemical reactions. Using everyday materials, kids can watch colors swirl in milk as soap interacts with fat molecules, breaking the surface tension.

How Soap Affects Liquid Surface Tension 🧼💧

Surface tension is the invisible force that keeps liquid molecules close together. When dish soap is added to milk, it disrupts this force by breaking up fat molecules. This reaction causes the milk to move, carrying food coloring along with it, creating a swirling effect.

📌 What You Need:

• Whole milk (higher fat content works best)
• Food coloring (various colors)
• Dish soap
• Cotton swab or toothpick
• Shallow plate

📌 Steps:

1. Pour milk into the plate, making sure it covers the bottom evenly.
2. Add several drops of different food colors in separate spots.
3. Dip a cotton swab into dish soap and gently touch the milk’s surface.
4. Observe how the colors swirl as the soap disrupts the surface tension!

How does dish soap work in a water surface tension experiment?

Food coloring alone does not mix with milk because milk’s fat content creates a stable surface. However, when soap is introduced, it reduces the surface tension, allowing the food coloring to move freely. This visually striking experiment demonstrates how liquids interact at a molecular level.

Diffusion Science for 3rd Graders with Skittles Experiment

Diffusion is the process where molecules move from areas of higher concentration to lower concentration. The Skittles experiment is a simple and colorful way to observe diffusion in action.

Observing How Colors Spread in Water 🌈💦

Skittles have a sugar coating that dissolves when placed in water. As the sugar dissolves, the food dye moves outward, creating vibrant color patterns.

📌 What You Need:

• A white plate
• Skittles (various colors)
• Warm water

📌 Steps:

1. Arrange Skittles in a circle along the edge of the plate.
2. Slowly pour warm water into the center, just enough to touch the candies.
3. Watch as the colors spread towards the center without mixing immediately.

How does the Skittles experiment show diffusion?

When water comes into contact with Skittles, sugar dissolves, and the colored dye diffuses outward. Because no stirring occurs, the colors remain separate for some time before eventually blending. This experiment visually explains how molecules naturally move and mix over time.

Color Separation Science for 3rd Graders with Chromatography

Chromatography is a scientific technique used to separate different components of a mixture. With a simple experiment using markers and water, kids can see how colors break apart into their primary pigments.

Experimenting with Marker Ink on Coffee Filters ✍️🧪

Certain marker inks are made from a mix of colors. By using chromatography, these hidden colors become visible as water carries the ink across the coffee filter.

📌 What You Need:

• Coffee filters
• Washable markers (black and other dark colors work best)
• A cup of water
• Tape or a pencil

📌 Steps:

1. Cut a strip of coffee filter paper.
2. Draw a thick dot of marker ink near the bottom of the strip.
3. Tape the top of the strip to a pencil and rest the pencil across a cup so that the bottom of the strip barely touches the water.
4. Watch as the water travels up, separating the ink into different colors.

How is chromatography used to separate colors?

Markers may appear to be a single color, but they are actually made of multiple pigments. As the water moves up the filter, the pigments separate based on their solubility, revealing different shades. This technique is commonly used in forensic science, chemistry, and even art restoration!

Surface Tension and Germs Science for 3rd Graders with Glitter Experiment

The glitter germs experiment is a great way to demonstrate how soap helps remove germs from hands. Using glitter as a stand-in for bacteria, kids can see how soap breaks surface tension and disperses contaminants.

How Soap Breaks Surface Tension and Repels Germs 🦠🧴

Water has strong surface tension, which allows light objects, like glitter, to float on the surface. However, adding soap disrupts this balance, causing the glitter to scatter and sink.

📌 What You Need:

• A bowl of water
• Glitter (fine works best)
• Dish soap

📌 Steps:

1. Sprinkle glitter onto the surface of the water.
2. Dip a clean finger into the water—notice how the glitter sticks.
3. Now, dip a soapy finger into the water and watch the glitter move away instantly!

What happens when you put glitter in water?

Glitter behaves like bacteria on the skin—it sticks easily and is difficult to remove with water alone. When soap is introduced, it breaks down oils and surface tension, making it easier to wash away dirt and germs. This experiment visually reinforces the importance of using soap for effective handwashing.

Buoyancy and Density Science for 3rd Graders with Dancing Corn

The dancing corn experiment is a fun way for 3rd graders to explore buoyancy and density using common kitchen ingredients. When corn kernels interact with carbonated liquid, they appear to “dance” as bubbles attach and detach from them.

How Carbon Dioxide Gas Makes Objects Move 🍿💨

When carbon dioxide gas is released in a liquid, it forms small bubbles that stick to the surface of objects submerged in the liquid. As bubbles build up on a corn kernel, they create enough buoyant force to lift it upward. Once the bubbles pop at the surface, the corn kernel sinks again, creating a continuous up-and-down motion.

📌 What You Need:

• Unpopped corn kernels
• A clear glass
• Club soda (or vinegar + baking soda mix)

📌 Steps:

1. Fill the glass with club soda or prepare a mixture of vinegar and baking soda.
2. Drop a handful of corn kernels into the liquid.
3. Watch as the kernels rise and fall repeatedly!

What was the conclusion of the Dancing popcorn experiment?

This experiment illustrates how density changes impact movement in liquids. Corn kernels are denser than water, so they initially sink. However, when carbon dioxide bubbles stick to them, the added buoyancy makes them float. Once the bubbles burst, the kernels become heavy again and sink.

Water Density Science for 3rd Graders with Hot and Cold Water

Water density changes based on temperature, and this experiment allows kids to see how warm and cold water behave when combined.

Why Hot and Cold Water Don’t Mix Easily 🌡️💦

Hot water is less dense than cold water because heat causes molecules to spread out. Cold water molecules are packed more tightly, making it heavier. When hot and cold water meet, they form distinct layers rather than mixing immediately.

📌 What You Need:

• Two clear glasses
• Hot water (dyed red)
• Cold water (dyed blue)
• An index card or plastic sheet

📌 Steps:

1. Fill one glass with hot red water and another with cold blue water.
2. Place an index card over the hot water glass and carefully flip it onto the cold water glass.
3. Slowly remove the card and observe the water layers.

What happens when hot water and cold water mix?

If the hot water is placed on top, the layers stay separate, as the hot water remains floating above the denser cold water. However, if the cold water is on top, the two mix quickly because the cold water sinks while the hot water rises.

Newton’s Laws Science for 3rd Graders with Balloon Rocket Race

Newton’s Third Law of Motion states that for every action, there is an equal and opposite reaction. A balloon rocket race is an exciting way to see this principle in action.

How Balloons Demonstrate Action and Reaction 🎈🚀

When air is released from an inflated balloon, the balloon moves in the opposite direction. The force of the escaping air pushes against the surrounding air, propelling the balloon forward.

📌 What You Need:

• A long string
• A balloon
• A straw
• Tape

📌 Steps:

1. Thread the string through the straw and secure both ends tightly to create a straight track.
2. Inflate the balloon without tying it, then tape it to the straw.
3. Release the balloon and watch it zoom along the string!

How does Newton’s third law apply to a balloon?

This activity helps kids visualize thrust and propulsion. By experimenting with different balloon sizes or adding weight, they can observe how force affects motion. This experiment introduces fundamental physics concepts in a hands-on way that makes learning fun.

Liquid Density Science for 3rd Graders with Lava Lamp Experiment

The lava lamp experiment is an exciting way to explore liquid density and immiscibility (when liquids don’t mix). Using household ingredients, kids can create a colorful, bubbling effect that mimics a real lava lamp.

Why Oil and Water Don’t Mix 🛢️💧

Oil and water have different densities and do not dissolve in each other because of their molecular structures. Water molecules are polar, meaning they have a slight electrical charge that makes them stick together. Oil molecules are nonpolar, meaning they don’t interact with water and stay separate.

📌 What You Need:

• A clear plastic bottle or glass
• Water
• Vegetable oil
• Food coloring
• Alka-Seltzer tablets

📌 Steps:

1. Fill the bottle about one-third full with water.
2. Pour vegetable oil on top until the bottle is almost full. Wait for the oil and water to settle into two layers.
3. Add a few drops of food coloring—it will sink through the oil and mix with the water.
4. Drop in a piece of Alka-Seltzer tablet and watch bubbles rise and fall like a lava lamp!

What is the science behind the lava lamp experiment for kids?

Alka-Seltzer reacts with water to create carbon dioxide gas, forming bubbles that carry colored water droplets to the top. Once the bubbles pop, the water sinks back down, creating a continuous lava lamp effect. This experiment visually demonstrates gas formation, density, and solubility in an engaging way.

More Fun Science for 3rd Graders to Try at Home

Encouraging hands-on science experiments helps kids develop curiosity, problem-solving skills, and a deeper understanding of scientific concepts.

Encouraging Curiosity with Easy Experiments 🔍

Simple experiments help children ask questions and make observations about the world around them. Some other easy activities include:

• Egg in Vinegar Experiment: Watch how an eggshell dissolves over time.
• Paper Towel Color Mixing: Learn about capillary action by watching colors move through paper.
• Balloon and Static Electricity: Use a balloon to make hair stand up or move small objects.

Expanding Science Knowledge with Hands-On Learning

Engaging in hands-on science helps kids apply concepts in real-life situations. Encouraging them to experiment, make predictions, and discuss results strengthens their critical thinking and reasoning abilities. Whether testing density, chemical reactions, or forces of motion, these fun projects make science an exciting adventure.

 

Making Science Fun and Memorable

Hands-on science projects provide 3rd graders with an exciting way to explore the world around them. By engaging in simple experiments, kids develop problem-solving skills, curiosity, and a love for discovery. These activities introduce foundational scientific concepts in a way that is both interactive and easy to understand.

Encouraging young learners to ask questions, test ideas, and observe results fosters critical thinking and creativity. Whether exploring buoyancy, chemical reactions, or density, each experiment offers a valuable learning experience. Science isn’t just about facts—it’s about wonder, exploration, and the excitement of discovery. Check you our summer school guide for parents to further develop your child’s interest in science!

For more reliable science resources and experiment ideas, check out these trusted sources:

✅ American Chemical Society’s Science Activities
✅ Science Buddies – Free Science Project Guides
✅ National Geographic Kids Science Experiments

Still Have Questions?

What are some of the best science projects for 3rd graders that use the scientific method?
Great 3rd grade science experiments include the bouncy egg, raisin dance, and red cabbage pH test. Each project requires clear steps to form a hypothesis, conduct an experiment, and analyze results—perfect for using the scientific method in an engaging way.

How can I find an easy 3rd grade science fair project with common household items?
Many easy 3rd grade science fair ideas involve common household supplies like vinegar, baking soda, or dish soap. Try fizzy reactions with antacid tablets, make oobleck to study non-newtonian fluids, or test air pressure with a balloon and bottle setup.

What are some cool 3rd grade science topics that explore physical and chemical changes?
Simple chemistry experiments like Play-Doh vs. baking soda reactions, sugar crystals growing, and identifying physical and chemical changes in cooking are all excellent ways to teach these science concepts to early elementary students.

Are there printable science resources or worksheets that go with these projects?
Yes, many science projects for 3rd grade include printable science worksheets to help students track the steps of the scientific method, write observations, and reflect on results. These support learning and can be used for both classwork and science fairs.

What are fun experiments that teach about living things or environmental science?
Try sprouting seeds to observe living things, create a mini water cycle bag for weather science, or explore how germs spread using glitter. These fun experiments connect real-world topics with hands-on experiments and activities.

Can you recommend a STEM challenge that fits a simple science theme?
Build a magnet maze to explore magnetism, design a testable paper airplane challenge, or compare materials for making the strongest bridge—these are excellent STEM challenges for curious minds.

What makes a project the best science fair project for 3rd grade?
The best 3rd grade science projects are age-appropriate, simple science activities that encourage kids to explore science independently. A strong project clearly follows the scientific method, uses familiar materials, and answers a question that’s both fun and testable.