SCIENCE WORK!!
Calculating Density
In this activity, you will calculate the densities of a number of objects
when given the mass and the volume of each.
1. In the Gizmotm, be sure the dropdown menu is set to
Styrofoam. Click Reset ( ) if that button is active. You will see a blue
block of styrofoam.
a. Drag the block to the tray labeled Material Investigation.
Details related to the object are displayed just above the tray. What is
the mass of the styrofoam block? What is its volume?
The mass is 7.28 grams. The volume is 36.4 cm3.
b. What is the density of the styrofoam block? (Density
is given by the formula shown below.)
The density of the object is 0.20 g/cm3.
c. Drag the block to the beaker of water. Does the block
sink or does it float? If it floats, about how much of the block is exposed
above the water's surface? (State your estimate as a fraction or as a percent.)
The Styrofoam does float in the beaker. The percent
of it out of the water is about 80%, or 8/10.
2. Return the block of styrofoam to its starting location.
Then select Wood from the dropdown menu.
a. Drag the wood block to the Material Investigation tray.
What are the mass and the volume of the wood block? Calculate the density
of the block. How does this value compare to the density of the block of
styrofoam?
The mass of the wood is 25.48 grams. The volume is
36.4 cm3. The density of the wood is 0.70 g/cm3. The density of the wood
is greater than the Styrofoam because the wood weighs more but the volume
is the same.
b. Drag the block of wood to the beaker. Does it float
or does it sink? If it floats, approximately how much of the block is exposed
above the surface of the water?
The wood floats in the beaker. Roughly 30% is showing
so about 1/3.
c. Which block floats higher in the water, the styrofoam
or the wood? Which of the two blocks has the greater density?
The Styromfoam floats higher becase it has the least
density out of the two objects. The wood is under the water more than the
Styrofoam because it has greater density.
3. Repeat the process with the aluminum block and the slate
block.
a. What are the densities of the two blocks? Show your
calculation.
The mass aluminum is 98.28 grams. The volume is 36.4
cm3. The density is 2.70 g/cm3. The mass of the slat is 76.44 grams. The
volume is 36.4 cm3. The density is 2.10 g/cm3.
b. Do these blocks sink or do they float?
Both these blocks sink.
c. Compare the densities of all of the objects that float
with the density of water, which is 1 g/cm3. How do the densities of the
floating objects compare with the density of water?
Well if they have a density over 1.00 g/cm then they
will sink. If they have a density of less than 1.00 g/cm3 they will float.
d. Consider the densities of the objects that sink. How
do the densities of these objects compare with the density of water?
Yes they do if ones to great they sink if to less then
it will float.
4. Return the current object to its starting location.
Select Unknown A from the dropdown menu.
a. What is the density of Unknown A?
The mass is 21.84 grams. The volume is 36.4 cm3. The
density is 0.60 g/cm3.
b. Do you expect Unknown A to float or to sink when it
is placed in the beaker?
If you expect it to float, estimate the how much of
the block will be exposed above the surface of the water. I expected it to
float in the breaker. I think that about 40%, or about 2/5.
c. Check your expectatiomn by dragging the block into the
beaker. What did you find?
I was correct about both estimates.
Slicing and Dicing
In this activity, you will explore the effect that cutting the various blocks
into smaller pieces has on the density of the pieces.
1. Return any blocks to the starting location. Select Styrofoam
from the dropdown menu. Look back in your work and find the density of the
styrofoam block (or just find its density again). Drag the block to the beaker
and remind yourself how high it floats. Then return the block to its starting
location. Click Slice to cut the block into smaller pieces. Select one of
these pieces and drag it down to Material Investigation.
a. What is the density of the smaller piece? How does this
density compare to the density of the original styrofoam block? Return this
piece to its starting location.
The density is 0.20 g/cm3. It has the same as the big
block.
b. Determine the density of another piece of the styrofoam
block. How does the density of this piece compare to that of the original
block and to the piece that you examined in the preceding step?
Yes it will have the same density as both blocks we
tested before.
c. Drag the piece of the styrofoam block to the beaker.
About how much of the floating block is exposed? How does this fraction or
percent compare to that for the original styrofoam block?
Most of the floating block is exposed about 80% is
exposed. It is about the same amount exposed.
d. Does density appear to be a property of a specific object,
or is it a property of the material from which the object is made? Justify
your answer.
It is the property of a specific object because
the object can be different and be a different density os it would have to
be the exact same material.
2. Repeat the experiment above for at least two pieces
each from the wood block, the aluminum block, and the slate block.
a. How do the densities of the smaller pieces of wood,
aluminum, and slate compare to the densities of the larger blocks of each?
Show your calculations.
They all compare because they all are the same densities.
b. Which would you expect to float, a large piece of wood,
or a small piece of slate, or both? Explain.
I would expect a large piece of wood to float because
its density is less than a small piece of slate.
3. Repeat the procedure for Unknown A and Unknown B. Do
your findings hold true for pieces of these materials? Explain.
Yes I my findings where correct because all of my answers
were correct.
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