Monday, 30 October 2017

Frozen Fun: Try These Cold-Weather Science Experiments

With absurdly low temperatures gripping the eastern half of the United States and Canada, several cities and towns have cancelled school for the day, leaving parents with youngsters stuck indoors — a recipe for cabin fever.

For those looking to keep their kiddos occupied, there's a way to use the extreme cold for some entertainment (and sneak in a little science education, too). Here, LiveScience has rounded up a few fun experiments that can be done with just a little time outdoors (make sure to bundle up!), from making frozen soap bubbles to creating your own colorful snow. (There's also one experiment to make sure the little ones don't try.)

Frozen bubbles
Kids love bubbles. And while summer is typically the time to crack open a bottle of bubbles, there's a way to make them work in the winter. If it's cold enough outside (this post at the blog Apartment Therapyrecommends temperatures below about 9 to 12 degrees Fahrenheit, or about minus 11 degrees Celsius), you can make the bubbles freeze. The trick is to blow them up in the air so that they have time to freeze before hitting the ground or another surface. The bubbles will form crystalline patterns and some might break, looking a bit like the shell of a cracked egg. Don't have any bubble solution handy? The post also has a simple homemade recipe. 

Maple syrup candy
Do just like Half Pint did in the "Little House on the Prairie" books and make your own maple syrup candy. Just heat butter and syrup together, according to this recipe, and after it cools, you can pour it onto fresh snow and it will harden into something like maple taffy. Yum!

Magic balloons

Okay, so maybe they're not magic, but they will seem that way to the kids, and this one is quite easy. Just inflate and tie up a balloon, then stick it outside and watch it deflate. Bring it back inside to warm up and watch it re-inflate. (This is a nice lesson in the volume of a gas, in this case, air volume, changes with temperature, shrinking in the cold, as its density increases, and expanding in the heat, as its density decreases.)

Make your own snow

This one is for those of you experiencing really cold temperatures. Meteorologist Eric Holthaus demonstrates it nicely in a video posted to Youtube (see it also below): If it's cold enough outside, you can take some boiling water throw it up in the air (make sure it will blow away from you), and it will freeze into snow. When Holthaus did his experiment in Viroqua, Wis., it was minus 21 F (minus 29 C) with a wind chill of minus 51 F (minus 46 C).

How does water turn into snow? Colder air holds less water vapor than warmer air, while the boiling water is giving off lots of water vapor (that's the steam you see rising from the pot). When the hot water is thrown into the cold air, the air gets more water vapor than it can hold, Mark Seeley, a climatologist at the University of Minnesota, explained previously to LiveScience's Life's Little Mysteries, so the water vapor clings to tiny particles in the air, crystallizing into snow. Seeley says it has to be quite cold to attempt this one, somewhere in the region of minus 30 F (minus 34 C) or lower.

Do NOT try this at home

One "experiment" to make sure the kids don't attempt is triple-dog daring anyone into sticking their tongue to that frozen flagpole. Maddie Gilmartin, 12, of East Kingston, N.H., gave this one a try and, sure enough, her tongue was frozen to the pole, as the New York Daily News notes. Her parents tried to blow warm air on her tongue and douse it with warm water to get it unstuck, but to no avail. Eventually the paramedics were able to free her; and her tongue is expected to recover, though it could take up to six months for the swelling to go down.
Why does this happen? The tongue is warm, and when it touches the frigid pole, the pole saps that warmth and cools the tongue, causing the body to send more heat to the cooled area. But the high thermal conductivity of the metal pole means it sucks up that warmth faster than the body can resupply it to the tongue. The upshot: The moisture on the tongue freezes in the pores of the tongue and the metal and, voila, you're stuck.

This is the first step on Mars / यह मंगल ग्रह पर पहला कदम है

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