Stuck at Home 3: Make orange slushies; find out what's in snow; dance!

Are your kids wondering why trucks are laying down salt on the roads? This explains the reason why and turns out a tasty treat! 

Fill about half of a sandwich baggie with orange juice. Seal it tight. Place this baggie in a bigger, gallon baggie and fill the rest up with ice. Then pour about 2 tablespoons of table salt into the ice and seal it tight. Kids can take turns shaking, turning and squishing the double baggie concoction for five to 10 minutes. The juice turns into a super thick slushy. 

The science behind this: Basically, salt lowers the freezing point of water, so salt on the roads means that the salty water can stay liquid at, say, 28 degrees. You might remember that the Titanic victims froze to death in 28 degree water because it was saltwater (ocean). Salt also lowers boiling point – the reason why you put salt in a pot of water to make it boil quicker.

Kids always want to eat snow, but do any of us really know what's in it? Bring some samples from different layers of the snow inside where you can melt it on a burner, then pour the melted snow through a coffee filter. Students are always amazed at how much dirt there is in even the whitest snow. This helps quite a bit in deterring them from eating it. On the other hand, when it’s at its freshest and untouched, sometimes bringing along sugar-sweetened Kool-Aid and making snow cones can be a great treat!

Estimate the fall speed of snowflakes. Watch snowflakes as they fall past an object of known height, e.g. a building. Speed = distance/time. If a building is made of 2.75” thick bricks with ½” of mortar between rows of bricks, then every 10 rows of bricks equals approximately three feet (32.5” to be exact). On average, snowflakes fall at a speed of approximately 3 feet per second or 10 rows of bricks every second. Activity extension: Calculate how long it takes snowflakes to fall to the ground from the cloud base. (idea courtesy of Marcia Politovich, National Center for Atmospheric Research, Boulder, CO)

Sublimation: It is also fun to try sublimation, where students imitate the motion of gas molecules, and then quickly switch to solid molecule motion without the intermediate liquid phase. Remember sublimation can go in both directions (solid to gas or gas to solid).

The museum staff also shared some other sites with fun indoor activities: