Cold Weather Experiments

When the temperature drops below freezing, head outside for these fun winter science experiments. They're perfect for snow days!

By Sarah Pottieger





What you’ll need:

  • Pipe cleaners (white if possible)
  • Scissors
  • String
  • Pencil
  • Wide-mouth jar
  • Borax (available in the laundry aisle; try 20 Mule Team)
  • Boiling water
  • Blue food coloring (optional)
  • Gloves to protect your kids’ hands (Borax can be an irritant)

What kids will learn: How crystals form over time

  1. Cut the pipe cleaner into three equal sections.
  2. Twist the sections together at the center to form a six-sided snowflake. Trim the edges if they’re uneven or can’t fit into the jar.
  3. Tie the string to one end of the “snowflake.” Tie the other end of the string to a pencil.
  4. Fill the jar with boiling water.
  5. Add three tablespoons of borax one at a time, making sure each spoonful dissolves before adding the next.
  6. Add food coloring if you want.
  7. Place the pencil across the jar’s mouth so the snowflake hangs inside the jar. It should be completely covered by liquid but not touch the bottom. (If it does, adjust the length of the string.)
  8. Leave overnight.

Ta-da! In the morning, your child will wake up to find a crystallized snowflake! Explain that crystals are formed when identical molecules join together and create repeating shapes that grow larger. In the case of this snowflake, the molecules are the compounds in Borax; in real snowflakes, the molecules are water. Talk about other types of crystals — diamonds, table salt. After your discussion, take your snowflake and hang it up on the tree (or wrap it up for the next holiday season)!


What you’ll need:

  • Bubble-blowing solution
  • Bubble wand
  • Temperatures below 32°F (the colder, the better)
  • Magnifying glass

What kids will learn: Why ice crystals form

  1. Bundle up and head outdoors.
  2. Have your child slowly blow a bubble, then catch it with his wand.
  3. Wait a few minutes for its soapy sheen to crystallize as the bubble begins to freeze — this will take anywhere from a few seconds to a few minutes, depending on the bubble’s size and how cold it is outside.
  4. As your child examines the crystal patterns with a magnifying glass, explain that water molecules move constantly, but when temps fall below freezing, they stick together and form ice crystals.
  5. Shatter your icy creation and blow some more bubbles. Blow some high into the air and see if they freeze before landing on the ground. Blow a bunch at once, then take turns guessing which bubble will freeze first.



What you’ll need:

  • Notepad
  • 12-inch (or higher) clear container
  • 12-inch ruler
  • Snow
  • Foil

What kids learn: Why liquid water is denser than ice

  1. Ask children to guess how much water is in a foot of snow and write their predictions on a piece of paper.
  2. After everyone’s made a guess, bundle up, grab the container, and head outdoors.
  3. Have your child place the ruler in the container; fill to the 1-foot mark with snow.
  4. Bring the container indoors and cover the top with foil to prevent melting snow from evaporating.
  5. Once snow melts, remove foil and measure the water with the ruler. If kids are baffled by how little remains, point out that as water freezes, the molecules form crystals, which expand and take up more space. When they melt, the space between them shrinks back down.



What you’ll need:

  • Weather app
  • Thermometer
  • Mitten
  • Timer

What kids learn: An understanding of how our body heat and insulators keep us warm

  1. Find out how cold it is outside with a weather app or outdoor thermometer.
  2. Have your child place an easy-to-read thermometer inside a mitten.
  3. Leave the mitten (with the thermometer inside) outdoors. Set a timer for five minutes.
  4. After a few minutes, have kids predict whether the mitten will “warm” it up. Surprise! The thermometer will read the same temperature as the air outside. Next, discuss how mittens are insulators; they keep hands toasty because they trap heat generated by our bodies.



What you’ll need:

  • Bucket or large plastic bowl
  • Ice
  • 4 plastic zip-lock bags (large enough to cover your kid’s hand)
  • Butter or shortening
  • Rubber bands

What kids learn: How blubber (the layer of fat between an animal's skin and muscles) helps whales and other marine mammals survive frigid waters

  1. Fill a big bucket halfway with cold water and ice.
  2. Coat the inside of a plastic zip-lock bag with four spoonfuls of butter.
  3. Have your child put a plastic bag on each hand, then stick one of his hands into the butter-filled pouch. Put the remaining empty bag over your child’s other hand.
  4. Secure the edges of both bags onto your child’s wrist (so no butter escapes) with rubber bands.
  5. Have your child dip both hands into the bowl, being careful to make sure no water gets inside. Which hand can they keep in the icy water longest? Explain how blubber acts as insulation, trapping body heat, and other ways animals (and people) can stay warm during the winter.

Source: Sean Musselman, K–5 science specialist for the Burlington, MA, public schools

Photo Credit: KidStock /Blend Images/Corbis Images

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