Comment

Comment by Boothby171 on December 12, 2011 at 10:49am

What I want to know is: if you take a half-full glass of water and put it in the freezer, is it still half full, or is it now half empty?

Comment by Boothby171 on December 12, 2011 at 9:32am

Thanks, Clarence; I was about to step in, myself......

Comment by Lary9 on December 12, 2011 at 6:30am

Cool link. Thanx, Ruth.

Comment by Clarence Dember on December 12, 2011 at 5:18am

mass/atom vs mass/ unit of volume .

Comment by AtheistTech on December 12, 2011 at 3:49am

Yes sir, Chris G, we are in agreement. I took a look at your profile and did not see math as one of your fortes. If you understood algebraic math better, I could give a better explanation why a 1/2 glass water has the same mass as the ice created from that 1/2 glass water, but surely has a different density. I am not an educator either, but I feel I have a good handle on Mass, Weight, and Density. Merry Hanukkah! Oops! Is it Happy Christmas? Or maybe Pleasant Kwanzaa? Oh shit on it! Happy Holidays! (including Happy New Year!)

Comment by Chris G on December 12, 2011 at 3:35am

We probably are in agreement.

Check this out.

Comment by AtheistTech on December 12, 2011 at 2:53am

@Chris G    I think we are in agreement.

Density=Mass/Area

If the Density changes, then either the Mass or the Area or both change.

In the example of the freezing of half a glass of water, the water does not lose or gain any mass. The Mass stays the same, but the Density and Area change.

1kg/centimeter cubed (Density)=1Kg (Mass)/1 centimeter cubed (area)

In this 1/2 cup water example: If the Density changes to .5kg/centimeter cubed, the Mass will stay at 1kg, but the Area will change to something like 2 centimeters cubed.

.5 kg/centimeter cubed = 1kg/2 centimeters cubed or .5=1/2 The Mass doesn't change, but the Density does.

Comment by Chris G on December 12, 2011 at 2:40am

Check out this web site about rubber expansion.

Air in a tire expands because of friction therefore the tire expands that doesn't mean that the rubber expands. The above web site says that rubber contracts with heat as written below:

Whether a material expands or contracts when it is heated can be ascribed to a property of the material called its entropy. The entropy of a material is a measure of the orderliness of the molecules that make up the material. When the molecules are arranged in an ordered fashion, the entropy of the material is low. When the molecules are in a disordered arrangement, the entropy is high. (An ordered arrangement can be thought of as coins in a wrapper, while a disordered one as coins in a tray.) When a material is heated, its entropy increases because the orderliness of its molecules decreases. This occurs because as a material is heated, its molecules move about more energetically. In materials made up of small, compact molecules, e.g., the liquid in a thermometer, as the molecules move about more, they push their neighboring molecules away. Rubber, on the other hand, contains very large, threadlike molecules. When rubber is heated, the sections of the molecules move about more vigorously. In order for one part of the molecule to move more vigorously as it is heated, it must pull its neighboring parts closer. To visualize this, think of a molecule of the stretched rubber band as a piece of string laid out straight on a table. Heating the stretched rubber band causes segments of the molecules to move more vigorously, which can be represented by wiggling the middle of the string back and forth. As the middle of the string moves, the ends of the string get closer together. In a similar fashion, the molecules of rubber become shorter as the rubber is heated, causing the stretched rubber band to contract

Read more: http://wiki.answers.com/Q/Why_does_heated_rubber_expand#ixzz1gJ54OlRp

If you fill a cup half full of water and put it in the freezer you will see it expands. Ice takes up more volume making is less dense. It has less mass or density per volume. 

Sorry I'm not able to explain this in writing very well. I'm not a teacher.

Comment by AtheistTech on December 12, 2011 at 1:35am

Yes, the ship building site had a definition of density that is 100% true. So the ice at the bottom of a glacier has more atoms in a cubic centimeter than a cubic centimeter of ice at the top of the glacier. All true, but what I was saying is that a one cubic centimeter of water has the same mass as the resulting ice. 

I would agree with you if you said "Ice has less mass per cubic centimeter than water that's why it floats.: Or "Ice is less dense than water that's why it floats."  Not "Ice has less mass than water that's why it floats." 

What you said confuses me because I think there is not enough information in your sentence: Ice has less mass than water that's why it floats.

Comment by Chris G on December 12, 2011 at 1:18am

I'm familiar with mass and inertia, and a mass of people. 

Look up mass, weight, density, and volume under shipbuilding to see another definition.

Maybe this will help.

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