Indoor STEM Activities for Snow Days

Illustration of stained glass snowflakes on a window. The title reads "Indoor STEM Activities for Snow Days".

Most everyone loves the first weeks of winter and even the first few days of a snowstorm, but soon STEMists become bored with cold, winter activities.  Keeping STEMists entertained while they are on holiday, or at home for a snow day, is a test for any parent. Check out these 5 indoor STEM activities that will keep your STEMists entertained, engaged and challenged, all while having a cool and groovy time!

Exploding Sandwich Bag

A chemistry STEM activity using everyday items.

Animated GIF that shows an exploding sandwich bag.  It shows baking soda folded into a paper towel and then dropped in a baggie with a vinegar and water solution.  The bag gets sealed and then a chemical reaction happens that causes the bag to POP.


  • Paper towels
  • Sandwich bag that seals completely and has no holes
  • 1 ½ tablespoons baking soda
  • ½ cup white vinegar
  • ¼ cup warm water
  • Scissors

First, ask your STEMists to draw, then cut, a 15 cm square onto a paper towel. Next, measure and scoop the baking soda onto the middle of the towel. Fold the towel inwards on four sides creating a small packet of powder.  Then, mix warm water and vinegar in a small cup or bowl, and pour into the sandwich bag. Seal the bag, leaving an opening big enough for the baking soda packet.

Ask your STEMist to quickly but carefully drop the folded paper towel filled with baking soda into the bag, then immediately seal it closed.

In your yard, let your child shake the bag. Then put it on the ground and stand clear! Your STEMists will witness the awesome chemistry of the ingredients as they produce carbon dioxide (vinegar + baking soda = carbon dioxide). The carbon dioxide will cause the bag to inflate and then burst at its seams, creating a loud popping noise.

Play the Memory Game

Test your memory with this STEM activity.

Illustration of a memory game.  A blue tray with a zebra toy, a spoon, a truck, a ping pong ball, a pencil, coins, paperclip and a popsicle stick.

Create your own memory game and test your STEMists observation skills. Gather 10 – 20 everyday household items (paper clip, small toy, pencil, dice, spoon, etc.) and place them on a tray.

Ask your STEMists to look at the items for one minute (younger children may need more time to look at the items). 

Now, ask your STEMists to close or cover their eyes while you remove several items from the tray.

Your STEMists will have to use their powers of observation to try and memorize all the items on the tray, and then challeng their memory when you remove several items and ask them which ones are missing!

Make this a true scientific experiment and record your observations on a chart to compare results. You could also do this activity at a different times of day and see how that changes the outcome.

Stained Glass Snowflake Window

Create snowflakes and decorate with this STEM activity.

Illustration of stained glass snowflakes on a window.


  • Colored Cellophane (cello sheets)
  • Scissors
  • Paintbrush
  • Dish soap
  • Water

Cut snowflake patterns using your cellophane sheets. Check out our instructions on how to cut a six point snowflake. After snowflakes are made, mix two parts dish soap to one part water, and apply to a window.  Then, place your cellophane snowflakes on the window. Step back and enjoy your groovy winter window art!

Chocolate Slime (NOT edible)

With this STEM activity you will create delicious smelling slime (but don’t eat it!).

Illustration of hands stretching chocolate slime.


  • 8 oz. clear washable school glue
  • 1 bottle liquid starch
  • Unsweetened cocoa powder
  • Brown food coloring/liquid watercolors 

This chocolate-y slimy goo will provide hours of play for your STEMists. 

  1. Empty glue into a bowl and add 3 Tbsp of unsweetened cocoa powder and 1/8 tsp of brown food coloring or liquid watercolor (if you think you need more color).  
  2. Stir until the cocoa powder is combined with the glue.  
  3. Next, add 10 oz. of liquid starch and mix.  If slime is sticky, add small amounts of liquid starch until your chocolate slime is no longer sticky and starts to pull away from the bowl.
  4. STEMists will have loads of fun with this brown stretchy slime. Have your STEMists take turns stretching and then measuring their slime to see who can stretch it the farthest. Keep an observation chart to compare who stretches the farthest. Your STEMists can also experiment with adding more or less starch and seeing if that makes the slime more or less sticky.

    Note: warm water will remove slime off hands and toys. Remember this chocolate slime is NOT edible.  Your slime can be stored in a sealed plastic bag for several weeks for more groovy time with slime! 

Play Minute-To-Win-It Style Games

These STEM activities provide fun for everyone!

Illustration of cups stacked in a pyramid.

Gather your neighbors and friends, or invite your whole family, to play Minute to Win It style games. The fun is not only in the playing of the games, it’s in the creation and engineering of the games that will really get your STEMists going.  You can use a timer for each game or to make the games accessible for STEMists of all abilities, play the games without a timer just for the fun of it.

Materials Suggestions for Minute to Win It Games:

  • Cups
  • Ping Pong Balls
  • Empty Kleenex Box
  • Straws
  • Skittles or other small round candy
  • Sandwich Cookies
  • Index Cards
  • Balloons
  • Panty hose
  • Tennis ball (or a wool dryer ball)

Here are some of our favorite Minute to Win It Games.

Stack Attack

Stack 24 cups into a pyramid and then take it down before 1 minute is up. To make it extra challenging use more cups (36 or 48).

Movin’ On Up

Use a stack of 8-12 cups of one color and 1 cup of a different color. Put the different colored cup on top of the stack. Set the timer and have your STEMist take the bottom cup and move it to the top and keep going until the different colored cup is on top again.

Yank Me

Place a cup face down and put an index card on top. Keep stacking cups and index cards until you have 5 cups in the stack. Then, try and remove each index card so that the cups fall into a collapsed stack.

Cookie Face

This is a game everyone can play at the same time. Line up your STEMists and have them tilt their heads back. Place cookie on each STEMist’s forehead. They have to get the cookie to their mouth without using their hands!

Chocolate Unicorn

Have the STEMists find a partner. One STEMist sits down and puts their head back. The other STEMist will stack cookies on their forehead (making a unicorn or narwhal horn). Keep stacking and see how many can be stacked before they fall down.

Junk in the Trunk

This game takes a little prep work. First, take an empty tissue container and cut a small slit on either side of the box bottom. Pull a string through one hole and out the other and make sure you have enough string to tie around your STEMists’ waist. Make two or more so that more than one STEMist can play at a time.

Tie the boxes around your STEMists’ waists and fill them each with 6-8 ping pong balls. Turn on some music and have them shake and shake some more to see who can get all of the ping pong balls out of their “trunk” first!

Suck it Up

Each STEMists gets two plates and a straw. Place 10-15 skittles on one of their plates. Have them move the skittles to the empty plate with only the straw.

Defying Gravity

Blow up one or two balloons per STEMist. Have them each keep their balloon(s) in the air for a minute. For more of a challenge have each STEMist keep two balloons in the air using one hand.

Elephant March

Place a tennis ball or wool dryer ball in one leg of a pair of pantyhose.

Place cups around the floor. The STEMist who will be the elephant will put the pantyhose on their head and swing the ball to knock over the cups.

For more challenging play during cold, winter snowy days, try a monthly-themed Groovy Lab in a Box.  There is no better way to educate your STEMists than to keep their minds working to create, design and solve, through the engineering design process and STEM-related activities. Our monthly box activates thinking, questioning, inquiring and original creation as we guide children through scientific inquiry and engineering design process.

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