Eyeing an Icicle

 

            Today's Snack: Make mini-popsicles in the freezer! Take an empty ice-cube tray and fill it with your favorite flavor of juice. Put one or two pieces of fruit into each little compartment. Grapes and cherries work great! Stick a wooden toothpick into each piece of fruit so that it sticks straight up, or at least out of the compartment. Freeze. It takes about an hour to freeze solid.

 

Supplies:

 

Icicle

Measuring tape, yardstick or ruler

Glass measuring cup

Scale

 

 

            When icicles form and hang down from the rooflines, they often look smaller than they really are. Next time you have a chance, if you live in a colder climate, be sure to have a grownup help you get a ladder or stepstool ready, and then when you see icicles, run outside and break one off.

 

 

Rush inside with it and measure its length in inches. Write down your measurement. You can wrap a cloth measuring tape around it at its thickest point, too, if you want to record its circumference - how many inches around it is.

 

            Now place it inside a measuring cup, and weigh the cup containing the icicle. Record that weight. Also, write down your guess: which weighs more, ice or water? We're going to find out by purposely melting our icicle.

 

But first, estimate how much water there is, frozen in your icicle. Is it one tablespoon? One cup? One gallon? Write down your estimate.

 

            Also estimate how much that water weighs. Record your estimate.

 

            When you're ready to start melting your icicle, keep it in the glass measuring cup so that it sticks straight up. You might have to prop it up.

 

            While it's melting, let's talk about icicles. They're spikes of ice that have formed when water is dripping from above, hits air temperatures below freezing, and the water re-freezes into ice. The most spectacular icicles are "ice columns," which are icicles that are so long that they touch the ground.

 

The good news about icicles is that they're pretty. The bad news is, they can signal that there is too much heated air escaping from the interior of a building. There should be more insulation added, most likely, when you see rows of long icicles on a house or building.

 

Worse, icicles are heavier than you think, and if they get too long and break off, they can do serious damage to anyone or anything that's below them. They also can literally tear off the overhangs, eaves or gutters that they are hanging from. And when icicles hang from tree branches, as we've seen all over the country in bad ice storms, if the icicles get too heavy, they can break off tree branches - even very large ones.

 

When your icicle is totally melted, get out your estimates, and get ready to see how you did.

 

First, how close did your estimate come to how much water is in the measuring cup? Did you think it would melt down into a lot more water than it did? Are you surprised, since your icicle seemed to be so long? Or did it create less water than you expected?

 

Second, weigh the measuring cup on the scale, and then pour out the water and weigh it again. Subtract the difference, and that will tell you how much the water that formed your icicle weighed. How close did your estimate of the weight of that water come to the actual figure you recorded, of the weight of the icicle?

 

Also, did you guess that the icicle would weigh more, or the melted water? They should weigh the same, because ice and water weigh the same. This exercise should teach you that molecules are molecules - even though the icicle seemed heavier because it was so long, its weight is exactly the same as the amount of water it melted down into. The melting process does not make it heavier or lighter.

 

 

           

Here's one more exercise:

 

Can you figure out how much water per inch of your icicle there was? For example, there are 8 ounces in a cup. If your icicle was 16 inches tall, and melted down into one-half of a cup of water, that's 4 ounces of water. If you divide 4 ounces by 16 inches, you get .25. That means that every inch of that icicle melted down into one-fourth of an ounce of water.

 

            It has a lot to do with the circumference of your icicle. Remember, that's a term for how big around your icicle is. Do you think thick icicles use more water per inch, or less?

 

Go ahead and guess how much water per inch your icicle melted down into. Then, using your records of how many inches long it was, and how much water it melted down into, figure it.

 

            If you got it right, or pretty close, congratulations. You not only ACED it - you ICED it!