When I think about summer, the first thought that comes to my mind is playing outside and enjoying life!  What better way to combine outdoor fun with science this summer to help prevent a summer slide than by creating science with chalk? Here are five outdoor STEM activities with chalk that you can try tomorrow!

1. DIY Washable Sidewalk Chalk Paint Recipe

The first step to getting summer started is by creating DIY washable sidewalk chalk paint. This recipe is a great way to bring up discussions about chemical and physical reactions and how different elements work with each other. You can use this recipe to make all the sidewalk chalk paint that you can use with the other summer chalk STEM activities in this list!


  • 7 Tablespoons of cornstarch
  • 7 Tablespoons of water
  • Food coloring of your choice
  • Small cups (one per color)
  • Spoon
  • Paint Brushes

In each cup, put one tablespoon of cornstarch and 1 tablespoon of water. Mix using the spoon, add food coloring, and mix again.

Done! Repeat the steps to complete all the different colors you want.

2. Sidewalk Chalk Calculator or 100s Chart

young girl doing math with chalk

Chalk can be a great tool for younger kids to practice their addition and subtraction skills. Have the kids write out the numbers 1-10 or 1-20. Then, have them walk up to the two numbers they want to subtract or add together and write the number sentence out in chalk. They can challenge their friends to solve the equations or solve them on their own. Finding a fun new way to look at numbers can help build math skills and help students become more passionate about math.

Kids can also create a 100s chart to practice their math skills. Having an entire 100s chart written out on the driveway is a great way to bring a visual to math, addition, and subtraction.

3. Chalk Shadows

child outline shadow with chalk

What better way is there to teach how shadows are affected by Earth’s orbit around the sun than by chalk? At 9 am, trace the outline of your shadow in a spot that is in full sun. Go back at 11 am, 1 pm, 3 pm, and 5 pm and trace the outline of your shadow each time to see how it changes as the sun rotates. Doing this will create a great discussion about how time, the sun, and the Earth are all related.

4. Draw Life-Sized Dinosaurs or Whales

life size dinosaur made from chalk

This is one of my personal favorite things to do during the summer. Research your favorite dinosaur or whale and draw the real-life dimensions of that animal. If the animal is 15 feet tall, measure out 15 feet to compare it to yourself. You can research a large variety of dinosaurs, animals, and sea creatures to compare their sizes by measuring and drawing them next to each other. This is such a fun activity to bring dinosaurs to life!

5. Blow-Up Chalk

While blowing up chalk might sound a little scary, but this is a fun activity that will help explore the scientific method and chemical reactions. This is a perfect activity for scientists of all ages.


  • White Vinegar, 1 cup
  • Cornstarch, 1 cup
  • Food coloring, several drops
  • Baking Soda, 1 tablespoon
  • Food coloring, several drops
  • Tissue
  • Quart or gallon resealable bag

First, put on safety glasses before beginning the recipe. Then start by filling a bag with one cup of cornstarch and one cup of vinegar. Mix the cornstarch and vinegar, add food coloring, and mix again well. Repeat for how many colors you would like to make.

On the tissue, place 1 tablespoon of baking soda and fold it so the baking soda will not fall out. Make one baking soda pouch for each bag that you made.

Before completing the chemical reaction, make sure you are still wearing safety glasses and that children are supervised by an adult. Open the corner of the bag and drop in the baking soda pouch. Quickly close the bag and give it a shake. Place the bag back on the ground, step a safe distance away, and watch the explosion! After shaking and prior to the explosion, you can also observe the gasses fill the bag. When baking soda mixes with vinegar, the mixture foams up with carbon dioxide gas, causing the explosion.

Looking for more summer STEM ideas? Check out these great activities on STEM Universe!