Ask Joe | Despite feel, water weighs more than ice

June 22, 2013 

Q: Why does ice seem to be so much heavier than the same amount of water?

— Linda

A: This was a fun one to calculate and answer, but the answer is going to surprise you a bit.

Water is a very unique substance because it expands when it freezes into ice. In fact, the density of ice is about 90 percent of water.

To make things simple, let’s talk about cubes of water and ice that are a meter on each side. The cube of water would weigh 1,000 kilograms but the cube of ice would weigh 900 kilograms.

So why is your observation different? I believe it’s because we’re really not asked to lift water as much as ice. If by chance a shovel could hold the same volume of water as what you would carry as ice, it would be heavier.

Let me add a little more detail to the answer as the most common thing we shovel is snow, and you may have noticed that not every snowfall is equal when it comes to weight. We’ll stick to the same cubic meter to make comparisons.

A fresh newly fallen dry snow may weigh less than 50 kg, but if you let it settle and there is less air mixed in with the snow, it may weigh more than 200 kg. A wet snowfall can weigh almost as much as ice, 800 kg for a cubic meter.

Q: Why does the water swirled up from the ocean during a hurricane come down as fresh water and not saltwater?

— Lou

A: This is one of the most common hurricane questions that I receive. It’s good news that it is fresh water falling as the salt water would be devastating to our ecosystems.

The vast majority of the moisture that fuels rainfall from a hurricane comes from evaporation from the water in the ocean. Oceans are made of saltwater so this is what causes some of the concern; however, water evaporates, but salt does not.

You can prove this to yourself by taking a pot of water. Add salt and then boil away the water. In the end all that will be left in the pot is the salt.

Now, I will add that there is a little in the way of saltwater spray that is brought up by the wind of a hurricane. But this is really only a factor over the ocean and right near the coastline where there usually is a little saltwater spray in the air. This is one of the reasons why cars at beach locations tend to corrode at a much faster rate than places that are farther from the oceans.  

If you have a question about the weather, you can write to Joe Murgo at 5000 Sixth Ave., Altoona, PA 16602 or email him at Murgo@wtajtv.com. Some questions will be answered here and all of the questions will be entered in a contest to be shown on WTAJ News at 5 p.m..

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