Chemical Change
Lesson 2
Describe Density as a
Physical Property of Matter
Make Accurate Measurements of
Mass and Volume
Calculate Density of Matter
Brainstorm part 1
Why do some things float in water and other
objects don’t?
 Discuss what objects sink and others float.
?

Did you observe any sinking, floating, or
layering in the previous activity?
Density Anticipation Guide

Check out the materials displayed on the table.
1. Wood Cube
2. Ebony Wood Cube
3. Plastic Cube
4. Steel Ball
5. Wooden Ball
6. Rubber Stoppers with and without holes
7. Cork
8. 10 paper clips
9. Packing Peanut
10. 2” X 2” Aluminum Foil
11. 4” X 4” Aluminum Foil
Teacher Demonstration


Q: How can we find out more about why
things float or sink?
A: MEASUREMENT!
1. Using a digital scale to measure mass
2. Using displacement to measure volume
3. Using math to measure volume
Length X Width X Height
4. Using multiples to measure the mass of
small items
Ok, Let’s start our investigation.



We will be measuring the mass and
volume of each item in the float and sink
bag.
Let’s do a trial run using the rubber
stopper.
And the answer is…………


Now measure the mass and volume of the
other items.
Ask each other:
1. What have you observed so far?
2. What did you expect to happen?
3. What patterns do you notice?
4. Can you draw a conclusion about all
the items that float?.......sink?
5. Have you compared the mass of
each item?.......the volume?
6. How are mass and volume related to sinking and
floating?
Continue your investigation.
Part 2
But first let’s double check our data.


Plot the data on the coordinate plane.
FLOAT
SINK
Draw a line separating the floating items
from the sinking items. (where X =Y)
Let’s Calculate Density
d=m/v


Does this tell you why some things sink and
others float?
Explain.
When mass is less than volume then it floats.
When mass is greater than volume it sinks.
Continue your investigation.
Evaluate
What
trends do you see in the data?
Why
does the stopper measure a greater
mass than the cork?
Does
size alone determine whether
something floats or sinks?