Voume, Mass, and Density

Today we started by answering three questions after looking at this table.

Volume Mass

Most evacuted 1000g 900g

Open to air 1000g 1000g

Pumped with 1000g 1100g
air
a) What happened to the volume of the container when to you filled it with air?
The volume stayed the same because the measurements of the container stayed the same.

b) What happened to the mass of the container, when you filled it with air.
It became heavier because you added more air particles.

Then we drew particles pictures of each situation, Most Evacuated, Open to Air, and Pumped up with Air.

We then did a quick experiment like the one we did in our homework once with a balloon in a vacuum. This time though we used a glove, and when we sucked the air out of the container with the glove in it, the glove expanded. There wwere no air particles blocking it from doing so.

We then went and did two problems.

Problem:
You have two identical beakers. one has 90ml of salt water, which has a mass of 100g. The other has 100 ml of tap water, which has a mass 100 g.

a) Make a particle picture of both liquids.
b) Which is denser? How do you know?

Reason

You have a pice of aluminum that has a mass of 21.6 g. The aluminum rectangle has a height of 1cm, a width of 2 cm and a length of 4 cm. Other piece of aluminum with a mass of 32.4 g has a height of 2cm, a width of 2 cm and a length of 3 cm,

a) Make a particle picture of both pieces. Are they the same or different?
b) What is r=the volue of each block?
c) If the mass of the particles is 21.6g for 8cm cubed what is the mass of the particles in each centimeter of the aluminum?

For the rest of the of the problem check our hw for tonight.

We also defined density.

Density- the amount of particles in the same amount of space

The one that that still cinfuses me is the density part. I don't have an idea for a unit rate or radio. I can see that mass Density and volume are related, I'm just not sure how.

Videos-

Balloon in vacuum: http://www.youtube.com/watch?v=VoiimTycDy8&feature=related
Volume and Density: http://www.youtube.com/watch?v=rxb

DB (3rd Round)