Stuck at Home 3: Make orange slushies; find out what's in snow; dance!
Posted February 12, 2014
Updated February 13, 2014
Never fear! The N.C. Museum of Natural Sciences offers up these home-based activities to keep you busy.
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.
Dancing is a great way to stay warm and active on these cold winter days. There's still time to enter the N.C. Museum of Natural Sciences' Birds of Paradise dance video contest. The submission deadline is Feb. 17. Click here for the details!
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)
Phase Change Exercises
Solid: Have the kids stand up (shake off those cobwebs!). First wiggle and move as much as possible while still keeping your feet firmly planted. This motion represents the molecular vibration of a typical solid.
Liquid: Next, let’s increase the energy, imagine a bit of heat was added. Now everyone gets to move as much as possible, but can only move one foot at a time. This motion represents the liquid phase; note that the individual molecules are occupying more space and the room suddenly seems more crowded.
Gas: In the gas phase simulation, students can move freely and each individual is encouraged to move the entire length of the room. CAUTION! The gas phase can be a bit unruly if you have an especially rambunctious group.
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: