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June 30, 2026

25 Easy STEM Activities for Kids Using Supplies You Already Have

Are you looking for easy STEM activities to keep your child entertained and off the screens? These ideas are not only easy but fun, and a great way to spark some creativity!

easy stem activities for kids

What is STEM?

STEM stands for Science, Technology, Engineering, and Math. While those subjects might sound intimidating, STEM activities for kids are really just fun, hands-on ways to encourage curiosity, creativity, and problem-solving through play.

Whether your child is building a marshmallow tower, making a homemade lava lamp, or testing which items sink or float, they're learning how to ask questions, make predictions, and discover how the world works. Best of all, they probably won't even realize they're learning because they'll be too busy having fun!

These simple activities are a great way to break up the usual routine of screentime and everyday toys while giving kids something exciting to create, test, and explore. You never know, one fun afternoon experiment could spark a lifelong love of science, engineering or technology. Even if it doesn't, your child will still be building confidence, critical thinking skills, and wonderful memories right alongside you.

Basic STEM Supply Kit

You may have many of these items around your house, but these supplies can make STEM activities even more fun:

  • Pipettes
  • Food coloring
  • Magnifying glass
  • Safety goggles
  • Craft sticks
  • Baking soda
  • Standard measuring cups
  • Clear cups with oz measurements
  • Plastic trays
  • Balloons
  • Toothpicks
  • Clear plastic cups

Easy Science Experiments for Kids

1. Baking Soda and Vinegar Volcano

This classic experiment never gets old. Kids love watching the fizzy eruption while learning about chemical reactions. And you're kidding yourself if you think you won't enjoy this just as much as the kids!

You'll Need

  • Baking soda
  • White vinegar
  • Small cup, bottle, or plastic container
  • Tray or baking sheet (to catch the mess)
  • Food coloring (optional, but fun)
  • Dish soap (optional for extra foam)

Instructions

Fill your cup or bottle about halfway with baking soda and place it on a tray. Add a few drops of food coloring and a small squirt of dish soap if you'd like extra foamy "lava," then slowly pour in the vinegar and watch the eruption!

What Kids Learn

This activity introduces kids to chemical reactions as baking soda (a base) reacts with vinegar (an acid) to create carbon dioxide gas. It's a fun way to observe cause and effect while making predictions about what will happen.

Try This Next

Experiment with different amounts of baking soda and vinegar to see how the eruption changes, or build a volcano around the bottle using playdough, clay, or dirt for an even more realistic experience.

2. Walking Water Experiment

Watch colored water appear to "walk" from one cup to another using only paper towels. This simple experiment is surprisingly fascinating and teaches kids that water can move in ways they can't always see.

You'll Need

  • 3 clear cups or glasses
  • Water
  • Food coloring (2 colors)
  • Paper towels

Instructions

Fill the two outside cups halfway with water and add a different food coloring to each one, leaving the middle cup empty. Fold two paper towels into strips, place one end in each water-filled cup and the other ends in the empty cup, then wait several hours as the colored water slowly travels into the center cup.

What Kids Learn

Kids discover capillary action, which is the process that allows water to move through tiny spaces. They'll also enjoy watching the colors mix together to create a brand-new color.

Try This Next

Ask your child to predict what color will appear in the middle cup before the experiment begins. Try different color combinations to reinforce both science and color mixing.

3. Sink or Float Challenge

Turn an ordinary afternoon into a science experiment by testing which household objects sink and which float. Kids love making predictions before finding out the answers.

You'll Need

  • Large bowl, sink, or plastic bin filled with water
  • A variety of small household objects (coins, toy cars, plastic blocks, corks, spoons, leaves, etc.)
  • Paper and pencil (optional)

Instructions

Gather several household items and ask your child to guess whether each one will sink or float before putting it in the water. Test each object one at a time and compare the results to their predictions.

What Kids Learn

Kids begin to understand concepts like density and buoyancy while practicing observation and prediction skills. They also learn that size isn't always what determines whether something floats.

Try This Next

Challenge kids to find five more objects around the house to test, or have them sort all the items into "sink" and "float" groups before making their predictions.

4. Rainbow Milk Experiment

This colorful experiment feels like magic as the food coloring swirls and dances across the milk. It's quick to set up and almost always gets an excited reaction.

You'll Need

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

Instructions

Pour enough milk into a shallow dish to cover the bottom, then add several drops of food coloring around the surface. Dip a cotton swab into dish soap and gently touch the center of the milk to watch the colors burst into motion.

What Kids Learn

The dish soap reacts with the fat in the milk, creating movement that makes the food coloring move around. Kids get a simple introduction to surface tension while enjoying a beautiful swirling visual experiment.

Try This Next

Try using different types of milk, such as skim or 2%, and compare the results. Ask your child which one they think will create the most colorful reaction before testing.

5. Grow Beans in a Clear Cup

Watching a seed sprout is a wonderful way to explore how plants grow. Since the roots are visible through the clear cup, kids can observe changes they normally wouldn't see underground. I loved this kind of thing as a kid! 

You'll Need

  • Clear plastic cup or jar
  • Dry bean (such as lima or pinto bean)
  • Paper towel
  • Water

Instructions

Place a damp paper towel inside the clear cup and tuck a bean between the paper towel and the side of the cup. Keep the paper towel moist and place the cup near a sunny window, checking each day for roots and sprouts.

What Kids Learn

Kids observe the stages of plant growth and learn that seeds need water, sunlight, and time to grow. Watching the roots develop first is often a fun surprise.

Try This Next

Measure your plant every few days and record its height in a simple journal or on a homemade growth chart. Once it has sprouted, transplant it into soil and continue watching it grow.

6. Ice Melting Race

This simple experiment encourages kids to make predictions while discovering how different materials affect the speed at which ice melts. It's an easy activity that uses supplies you probably already have.

You'll Need

  • Ice cubes
  • Several small plates or bowls
  • A variety of materials (such as aluminum foil, plastic, fabric, paper towel, wood, or a metal spoon)
  • Timer or stopwatch (optional)

Instructions

Place one ice cube on each material and ask your child to predict which one will melt the fastest. Observe the ice over the next 15 to 30 minutes and compare the results to their predictions.

What Kids Learn

Kids get an intro to heat transfer and discover that some materials conduct heat better than others. They also practice making observations and comparing results.

Try This Next

Repeat the experiment in a sunny spot and then in the shade to see how the environment affects melting time.

Another idea- after testing different materials, sprinkle salt on one ice cube and leave another plain. Ask your child which one they think will melt first, then compare the results.

7. Static Electricity Balloon Experiment

Who knew a balloon could perform magic tricks? This activity introduces kids to static electricity by showing how invisible electrical charges can make objects move. Kids love this one!

You'll Need

  • Balloon
  • Small pieces of tissue paper or paper confetti
  • Optional: an empty soda can

Instructions

Blow up the balloon and rub it against your kid's hair or a wool sweater for about 20 seconds. Hold the balloon near the paper pieces or an empty soda can and watch them move without being touched.

What Kids Learn

Children discover static electricity and learn that electrical charges can attract lightweight objects. They'll also begin to understand that not everything in science can be seen.

Try This Next

See if you can make the balloon stick to a wall or compare what happens after rubbing it on different fabrics.

8. Homemade Lava Lamp

Remember how much we loved our lava lamps? Create your own bubbling lava lamp with just a few kitchen ingredients. Kids love watching the colorful bubbles rise and fall over and over again- just like we did!

You'll Need

  • Clear bottle or jar
  • Vegetable oil
  • Water
  • Food coloring
  • Effervescent tablet (such as Alka-Seltzer)

Instructions

Fill a clear bottle about three-quarters full with vegetable oil, then add water until it's nearly full. Add several drops of food coloring, then drop in pieces of an effervescent tablet one at a time to create colorful bubbles. Let kids try different color combinations for extra fun.

What Kids Learn

Kids observe that oil and water don't mix because they have different densities. They also see how the gas produced by the tablet carries the colored water upward before it sinks back down.

Try This Next

Try different food coloring combinations or shine a flashlight behind the bottle to create an even cooler lava lamp effect.

Try making a second lava lamp using a different bottle or changing the amount of oil and water. Which version creates the biggest or longest-lasting bubbles?

Building and Engineering Activities for Kids

9. Popsicle Stick Bridge

Can your child build a bridge that's strong enough to hold a small toy or a handful of coins? This engineering challenge encourages creativity, problem-solving, and persistence. Kids can compare designs and discover which structures are strongest. 

You'll Need

  • Craft sticks (popsicle sticks)
  • School glue or a hot glue gun (adult use only)
  • Small objects for testing (toy cars, blocks, or coins)

Instructions

Challenge your child to build a bridge using only craft sticks and glue. Once the glue has dried, test how much weight the bridge can hold before it bends or breaks.

What Kids Learn

Kids explore engineering by designing, building, testing, and improving their creations. They'll also see how strong structures often use triangles and evenly distributed support.

Try This Next

Build a second bridge using a different design and compare which one holds the most weight.

10. Marshmallow and Toothpick Tower

This activity turns simple snacks into an exciting engineering challenge. Kids will quickly discover that sometimes the strongest designs aren't the tallest ones.

You'll Need

  • Large marshmallows or mini marshmallows
  • Toothpicks

Instructions

Challenge your kid to build the tallest free-standing tower they can using only marshmallows and toothpicks. If the tower falls over, encourage them to redesign it and try again.

What Kids Learn

Kids practice engineering, spatial reasoning, and problem-solving as they test different building techniques. They also learn that improving a design often takes several attempts.

Try This Next

Give everyone in the family the same number of marshmallows and toothpicks and see who can build the tallest tower, or challenge kids to build a tower that can support a small toy on top.

11. Paper Airplane Contest

Paper airplanes are a classic activity, but turning them into a STEM challenge makes them even more exciting. Kids will have fun testing different designs to see which one flies the farthest or stays in the air the longest.

You'll Need

  • Printer paper
  • Measuring tape (optional)
  • Paper and pencil (optional for recording results)

Instructions

Fold one or more paper airplanes using different designs. Fly each airplane from the same starting point and compare how far each one travels or how long it stays in the air.

What Kids Learn

Kids explore aerodynamics, including how wing shape, weight, and balance affect flight. They'll also practice making predictions and comparing results.

Try This Next

Once you've found the best-performing design, make one small change- such as longer wings or a folded nose- and test it again. See if the change helps or hurts its flight.

12. Cardboard Marble Run

Transform empty cardboard tubes into an exciting marble race. Kids can experiment with different layouts while discovering how gravity and angles affect speed.

You'll Need

  • Empty paper towel or toilet paper rolls
  • Painter's tape or masking tape
  • Marbles or small balls
  • Wall, large piece of cardboard, or the side of the box

Instructions

Tape the cardboard tubes to a wall or large piece of cardboard, creating a path for the marble to travel from top to bottom. Test your marble run, then adjust the angles or add more tubes until it rolls smoothly.

What Kids Learn

This activity introduces gravity, momentum, and engineering design. Kids also learn that testing and improving a design is an important part of the engineering process.

Try This Next

Challenge your child to build a longer marble run or add twists, turns, or jumps without letting the marble fall off the track.

13. Balloon-Powered Car

Turn everyday household materials into a car powered only by air. Kids are always amazed to watch their homemade vehicle zoom across the floor.

You'll Need

  • Small cardboard box or sturdy piece of cardboard
  • Four bottle caps
  • Two wooden skewers
  • Two drinking straws
  • Balloon
  • Tape
  • Scissors (adult assistance may be needed)

Instructions

Attach the bottle caps as wheels using the skewers and straws as axles. Tape a balloon securely to a straw on top of the car, inflate the balloon through the straw, pinch it closed, place the car on a smooth floor, and let go to watch it race away.

What Kids Learn

Kids see Newton's Third Law of Motion in action as the escaping air pushes the car forward. They'll also discover how small design changes can affect how well the car moves.

Try This Next

Encourage kids to adjust the wheel placement, balloon size, or weight of the car and test again to see how each change affects its speed and distance.

14. Aluminum Foil Boat Challenge

Can your child build a boat that holds dozens of pennies without sinking? This simple challenge is surprisingly fun and encourages creative problem-solving.

You'll Need

  • Aluminum foil
  • Large bowl, sink, or plastic bin filled with water
  • Pennies or other small coins

Instructions

Give each child a sheet of aluminum foil and challenge them to build a boat that floats. Place the boat in the water and slowly add pennies one at a time until it sinks, counting how many it was able to hold.

What Kids Learn

Kids discover how shape affects buoyancy and why some designs can support more weight than others. They'll also practice engineering by improving their designs after each test.

Try This Next

Build a second boat with a completely different shape and see if it holds more pennies than the first. Ask your child what changes they think made the biggest difference.

15. Egg Drop Challenge

This classic STEM activity encourages kids to think like engineers as they design a way to protect a fragile egg from breaking during a fall.

You'll Need

  • One raw egg
  • Cardboard
  • Cotton balls
  • Paper
  • Straws
  • Tape
  • Rubber bands
  • Any household materials you'd like to use

Instructions

Challenge your child to build a protective container for a raw egg using only household materials. Once it's complete, carefully drop it from a safe height and check to see whether the egg survived.

What Kids Learn

Kids practice engineering, creativity, and problem-solving while learning that testing, failure, and redesign are all part of the design process.

Try This Next

If the egg cracks, ask your child what they think caused it and redesign the container to solve that problem. Then test it again from the same height- or an even higher one if it survived the first drop!

16. Paper Helicopter Drop

Paper helicopters are easy to make and surprisingly fun to test. Kids will enjoy watching them spin through the air while experimenting with different designs.

You'll Need

  • Printer paper
  • Scissors
  • Paper clips
  • Pencil (optional)

Instructions

Cut and fold a simple paper helicopter using printer paper, then attach a paper clip to the bottom. Drop it from a chair or staircase (with adult supervision) and watch it spin to the ground.

What Kids Learn

Kids explore gravity, air resistance, and how changing the size or weight of an object affects the way it falls.

Try This Next

Make another helicopter with longer blades or an extra paper clip. Which one stays in the air the longest?

Math Activities That Feel Like Play

17. LEGO Pattern Building

Build and extend color patterns using LEGOs. Younger children can start simple while older kids can create more complex sequences.

You'll Need

  • LEGO bricks or similar building blocks

Instructions

Start a simple pattern using different colored bricks, such as red-blue-red-blue, and ask your child to continue it. As they become more confident, create more challenging patterns using additional colors or shapes.

What Kids Learn

Children practice recognizing patterns, sequencing, and logical thinking, which are important early math skills.

Try This Next

Challenge your child to invent their own pattern and see if you can figure out the rule before they explain it.

18. Measuring Cup Water Station

Water play becomes a hands-on math lesson with this simple activity. Kids can explore measurement while having fun pouring, comparing, and experimenting.

You'll Need

  • Measuring cups
  • Measuring spoons
  • Large bowl, sink, or water table
  • Water

Instructions

Fill a large container with water and let your child use measuring cups and spoons to pour water between containers. Encourage them to compare amounts and see how many smaller cups fill a larger one.

What Kids Learn

Kids develop an understanding of volume, measurement, estimation, and basic math concepts through play.

Try This Next

Ask questions like, "How many ΒΌ cups does it take to fill one cup?" Then test their prediction together.

19. Coin Sorting Challenge

Turn spare change into a fun math activity that helps kids practice counting, sorting, and recognizing different coins.

You'll Need

  • A handful of mixed coins
  • Small bowls or cups
  • Paper and pencil (optional)

Instructions

Mix several coins together and ask your child to sort them by type. Older children can count how many of each coin they have and calculate the total value.

What Kids Learn

Kids practice sorting, counting, identifying coins, and building early money skills.

Try This Next

Hide a few extra coins around the room and turn it into a coin hunt before sorting and counting everything together.

20. Shape Hunt Around the House

Learning about shapes becomes much more exciting when kids discover them in everyday life.

You'll Need

  • Paper
  • Pencil or crayons
  • Clipboard (optional)

Instructions

Choose a shape, such as a circle, square, or triangle, and search your home for objects that match. Draw or write down each item as you find it.

What Kids Learn

Children strengthen shape recognition while realizing that math is all around them in everyday objects.

Try This Next

After finding basic shapes, challenge your child to look for three-dimensional shapes like cubes, cylinders, and spheres.

21. Graph Your Favorite Snacks

Collecting data becomes much more fun when it's about favorite foods! Kids get an introduction to graphing while learning how information can be organized visually.

You'll Need

  • Paper
  • Markers or crayons
  • Family members to survey

Instructions

Ask each family member to vote for their favorite snack, then create a simple bar graph showing the results. Talk about which snack received the most and fewest votes.

What Kids Learn

Kids practice collecting data, counting, comparing numbers, and interpreting graphs.

Try This Next

Survey something new, like favorite animals, colors, or ice cream flavors, and compare the results with your first graph.

Screen-Free Coding Activities for Kids

22. Human Coding Game

This activity is basically Simon Says with a coding twist. Kids learn that computers must follow directions exactly, making it a great introduction to programming concepts.

You'll Need

  • Open space to move
  • Paper and pencil (optional)

Instructions

This activity is basically Simon Says with a coding twist. Give your child simple commands like "Take three steps forward," "Turn left," or "Hop two times." If they miss a step or do something different than instructed, call out "Bug Found!" and have them return to the last correct step before trying again, just like programmers debugging computer code.

What Kids Learn

Kids begin thinking like programmers by following precise instructions and learning how small mistakes can change the outcome.

Try This Next

Have your child become the "programmer" and give you the commands instead. Pretend to accidentally make a mistake and see if they can find your "bug."

23. Obstacle Course Algorithms

Kids become programmers by creating step-by-step directions for navigating an obstacle course.

You'll Need

  • Pillows
  • Chairs
  • Tape
  • Stuffed animals
  • Any safe household objects for obstacles

Instructions

Build a simple obstacle course, then challenge your child to write or say the exact steps someone would need to follow to complete it. Then have a parent or family member go through it and see if the directions were accurate! They quickly discover why clear instructions matter.

What Kids Learn

Children discover the importance of giving clear, detailed instructions while practicing sequencing and logical thinking.

Try This Next

See if your child can improve their instructions after watching someone else attempt the course. Were any important details missing?

24. Binary Name Bracelet

Computers use binary code to store information, and this activity lets kids create their own secret message bracelet while learning about this fascinating concept.

You'll Need

  • Two colors of beads
  • String or elastic cord
  • Printed binary alphabet chart

Instructions

Choose one bead color to represent 1s and another to represent 0s. Use a binary alphabet chart to translate your child's name into code, then string the beads together to create a one-of-a-kind bracelet. Kids love creating secret message bracelets while learning one of the basic ways computers store information. Free binary code chart can be found online.

Brace yourself to hear all the boop-boop-beeps during this one.

What Kids Learn

Kids discover one of the ways computers represent letters and numbers while practicing careful observation and following patterns.

Try This Next

Once they've mastered their name, challenge them to spell a sibling's name or a favorite word. See if someone else can decode the bracelet using the binary chart.

25. Secret Code Treasure Hunt

Turn your house or backyard into an exciting treasure hunt by hiding clues written in a secret code. Kids will love solving each clue to find the next one.

You'll Need

  • Paper
  • Pencil or markers
  • Small prize or treasure
  • A simple secret code or cipher

Instructions

Create a simple code by assigning each letter a different symbol or shifting each letter one place in the alphabet (for example, A=B, B=C, and so on). Write several clues using your code, hide them around the house, and place a small prize at the final location. Give your child the code key so they can decode each clue before moving on to the next. Kids feel like real detectives while they try to figure out the words in the clues!

What Kids Learn

Kids strengthen problem-solving, critical thinking, and pattern recognition while discovering how codes are used to send hidden messages.

Try This Next

Once your child understands how the code works, let them create their own coded treasure hunt for a sibling, friend, or parent to solve.

Our Favorite STEM Supplies for Kids

If your kid loved these activities, there are lots of ways to foster their interest in STEM topics- the ideas are endless. Here are some fun things to introduce that also make amazing gifts for birthdays and holidays!

  • Magnetic tiles
  • Kids microscope (this is so fun to use outside!)
  • STEM challenge cards
  • Snap circuits
  • Magnet movers kit
  • Science kit (my kids ask to do these activities on a regular basis!)

This post was all about fun and easy STEM activities for kids that you can do at home to beat boredom and foster curiosity and creative thinking in your kids.

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