Warmup 9/2/15
How do you know if you got the right answer in a lab
experiment?
Objective
To learn about calculating
density hands-on
Tonight’s Homework
Read section 2.2
Do p 30: 1, 2, 3, 4
Lab on Mass, Volume, Density
Today we’re going to do a lab on investigating
mass, volume, and density. (In pairs)
Mr. C. is going to do an example or two with you guys,
then let you loose to do the rest by yourselves.
But first, let’s go over a few pre-lab questions:
1) How would you get the density for one of the wood
blocks? (How are you going to measure mass and
volume?)
2) How would you get the density for water?
3) How would you get the density for something like the
glass stopper? (Hint: what would you see if you put it
into a graduated cylinder of water?)
Lab on Mass, Volume, Density
To get the density for a block, we need to measure
its mass and its volume. We can get mass by placing it on
the scale. We can get volume by measuring the sides and
multiplying.
To get the density of water, we also need mass and
volume. We can get the volume by looking at the
graduated cylinder and writing how many milliliters we
have. To get mass, we need to compare an empty
graduated cylinder with the one that has water. We need
to look at their difference in mass. That’s how much the
water weighs.
Lab on Mass, Volume, Density
To get the glass stopper, we need mass and volume. We
can get mass by putting it on the scale. Volume is harder,
though. To get volume, we need to put it in a graduated
cylinder that has water. After we put it in, the water level
will go up. The difference in how much it went up tells us
the stopper’s volume in milliliters. Yep, we’re getting the
volume of a solid in milliliters. Weird!
Lab on Mass, Volume, Density
Let’s go ahead and start setting up our lab write
up as a class.
Let’s do:
Purpose
Hypothesis
Materials
Data (table)
Lab on Mass, Volume, Density
Purpose
To find the density of several different materials.
Hypothesis
(Compare each thing to water (which equals 1). If it
floats, it probably has a density less than 1. If it sinks,
it’s more than 1. If it really sinks fast, maybe its 6 or 7!)
Materials
Plastic cube, wooden cube, glass stopper, cork, penny,
water, mineral oil, scale, ruler, graduated cylinder
Data (table)
plastic
Mass
Volume
Density
wooden
glass
cork
penny
water
oil
Lab on Mass, Volume, Density
Ok. From here, you’re ready to start doing your
experiment. Take careful measurements as you go.
Also, as you work, write down as precisely as possible
what you’re doing. Later, we’ll make our procedures. Mr.
C. will watch as you work, and help if you need it.
Find the density of the penny, the plastic cube, and the
wood cube. (volume of a penny = ∏r2h)
Find the density of the cork and the glass stopper
Find the density of water and of the oil.
Lab on Mass, Volume, Density
Ok. From here, you’re ready to start doing your
experiment. Take careful measurements as you go.
Also, as you work, write down as precisely as possible
what you’re doing. Later, we’ll make our procedures. Mr.
C. will watch as you work, and help if you need it.
Find the density of the penny, the plastic cube, and the
wood cube. (volume of a penny = ∏r2h)
Find the density of the cork and the glass stopper
Find the density of water and of the oil.
Lab on Mass, Volume, Density
For our analysis, let’s look over the answers we got
and see if they make sense. For each object, tell me
if the density you got was more or less what you
expected. Also, tell me what you could do to make your
answers better if you had to do this lab again.
For your conclusion, tell me what you learned about
density.
Exit Question
What was the density of the penny?
3.0
4.7
5.5
6.1
7.2
8.8
g/cm3
g/cm3
g/cm3
g/cm3
g/cm3
g/cm3