# 3.1-3.5

## 3.2 Mass and Volume

Purpose: To determine if the mass of a 1cm3 object will depend on its shape or the substance it is made of.

Procedure:

1. Find the volume of each long cylinder using water displacement in a graduated cylinder
3. Clean pan/zero balance
4. Mass 3 aluminum cylinders separately
5. Mass smaller aluminum cylinder
6. Mass brass cylinder
7. Answer the rest of the blue dots
Materials:

• 3 long aluminum cylinders
• 1 short aluminum cylinder
• 1 brass cylinder
• Water
• Balance
Blue Dots:

1. Yes, because they are the same size and are the same substance.
2. The new cylinder would have a mass of 5.404 grams.
3. The new cylinder would have a volume of 2.0 cm3.
4. I can find the mass of 1 cm3 of this new cylinder by dividing its mass by 2.
5. The short aluminum cylinder has a mass of 2.793 grams.
6. The shape of the piece does not affect the mass.
7. No, the brass cylinder cannot have the same mass and volume as a piece of aluminum because they are different substances.
Post Lab:

Same mass within sensitivity of balance

Experimental Errors:

• Mix up long cylinders
• Cylinder could be wet during Mi, increase in mass
• Water splashes out of graduated cylinder, decrease in volume

## Mass and Volume Notes

1. Objects that are made of the same substance that have the same volume, will have the same mass (regardless of their shape) (ex: tall and short aluminum cylinders)
2. The mass of an object will double if its volume doubles.
3. Objects that have the same volume but are made of different substances will NOT have the same mass.
Density:

• Always the same, determines what a substance is
• D = m/v
• g/cm3 (grams per cm3)
• Brass is more dense than aluminum

## Box Questions pages 46, 47, 48

46:

3. 8.1 g (C)

4. 5.1 g (A)

5. aluminum (B)

47-48:

6a. Yes, because wheels are part of automobiles so the amount of automobiles affects the number of wheels.

6b. No, the number of wheels per automobile does not depend on the number of automobiles. It depends on the type of automobile.

6c. Yes, the number of wheels per automobile does distinguish 1 automobile from another.

8. The graph would be a horizontal line because all aluminum has the same density.

## 3.5 The Density of a Solid

Purpose: To utilize density to determine if 3 metal objects are made of the same substance.

Procedure:

1. Clean pan/zero balance
2. Mass 2 cubes on balance
4. Mass the slab and compare its mass to that of the 2 cubes
6. Measure the dimensions of the 3 and calculate the volume and density of each
7. Find volume and mass of a rock
8. Calculate density of a rock

Materials:

• Rock
• Ruler
• 3 metal objects
• Water
• Balance

Blue Dots:

1. Cube 2 has a greater density. (if the volume is the same, the greater mass means a greater density)
2. No, because we do not know what the slab's volume is. (and it's bigger)

Histogram:

• Shows that cube 1 and the slab are most likely the same substance. Cube 2 is a different substance.
Rock:

• All of the rocks have different densities because the rock is formed by many substances being compressed together.
• Different substances = different densities
• If a substance is pure, even if it's broken up, every piece will have the same density

Experimental Errors:

• Water splashes out of graduated cylinder
• Paint is chipped off of object, lose mass
• Measure same slab side twice
• Find volume of rock before mass, greater mass and density

## Box Questions page 51

13. 1.7 g/cm3

14a. 10.5 g/cm3

14b. 2.14 g/cm3

14c. 0.82 g/cm3

15. 1. Zero balance/clean pan

2. Mass block

3. Measure dimensions with a ruler

4. Multiply l x w x h

5. Calculate density (m/v)

16. No, density depends on the substance, not size.

17. Yes, density is the same (both limestone), so mass/volume must be the same.