by Sarah Kinney

When winter arrives in the Northeast, the familiar world is transformed. Animals vanish, either migrating or hibernating. Frost forms delicate patterns on your windows. Temperatures drop and days get shorter. These seasonal changes create countless learning opportunities. Teach your children about winter with a few simple science projects.

1) Make instant snow. The concept is simple: parents should boil water and toss into very cold air. Staff at the Mount Washington Observatory have recorded this on several occasions. The water vapor of the boiling water freezes faster when it’s spread out from being tossed. This process is called deposition or desublimation. For best results, water temperature should be hotter than 200 degree Fahrenheit and air temperature should be colder than -20 degrees Fahrenheit. Just make sure not throw the boiling water in the direction of people. You will wow your kids with your seemingly magical snow-making skills, and you can sneak in some facts on phases of matter.

2) Be a human sundial. Use a compass to find north, draw a yard-long chalk line on the ground or use food coloring and water to paint on snow, and label the correct end with an “N.” Then, draw a line perpendicular through it to form a giant “X” and make a circle around the “X.” When the sun is out in the middle of the day, have you child stand in the middle of the circle and help them trace their shadow. Label the shadow with the date and time. Repeat over several days to see if the days are getting longer or shorter. If days are getting longer, the sun will be higher in the sky and your child’s shadow will be shorter.

3) Freeze bubbles. When the temperature dips below zero, have your children try and blowbubbles. If you don’t have a bubble-blowing kit, make the solution with six parts water, one part dish soap, and one part corn syrup, and use a straw to blow. Bubbles are formed by hundreds of water molecules stuck together with inter-molecular forces called surface tension. Depending on the air temperature and the warmth of your child’s breath bubbles can take longer to freeze. Also, observe whether the bubble’s size affects how long it lasts.

4) Identify frost. There are four commonly seen types of frost: radiation frost (hoarfrost), advection frost, window frost, and rime. Frost forms when an object cools below zero and water vapor in the air forms crystalline structures on it. Radiation frost develops on outdoor objects, like plants, as the objects become colder than the air. Advection frost is small ice spikes that form when a cold wind blows over trees, poles, and other surfaces. Window frost occurs when there is cold air on one side of the glass and warm moist air on the other side. Rime ice forms in very cold, wet, and windy climates. This is different from clear ice (think ice cubes) because it is less dense. Each type of frost has a distinct crystal structure from lacy to spikey. See if your kids can find each type.

5) Melting art. Start by freezing a block of ice in a plastic container (like a milk jug). When frozen, sprinkle one side with salt and let your kids decorate with food coloring. As the salt melts the ice, your children can watch as the colors seep into the block. Salt lowers the freezing point of water, which is why it is used to melt icy roads.

6) Capture a snowflake. Send your children outside with a sheet of black construction to catch falling flakes. Give them a magnifying glass, and let them see for themselves that no two snowflakes are the same. A single snowflake can have thousands of water vapor droplets. Snowflakes differ based on the humidity, but all are six-sided. Tip: Cool down the construction paper in a refrigerator or porch before collecting snow to make the flakes last longer before melting.

7) Who is asleep and who moved away? In the winter time, some animals migrate and others hibernate. Go exploring with your children and see what animal signs you can find. Some small animals hide out under ground. Some, like frogs, allow themselves to freeze. Some hibernate or sleep for long periods at a time, like bears and bats. Birds migrate to warmer climates. Are there any critters they expected to see, but couldn’t find? Look up what the animal’s winter routine is.