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Sink or
Float...and other Good Stuff with Density!!
A Webquest
for Science Students
Focus Questions and Links
Your group of four to six students will decide how to find the necessary
information to answer all of the questions below and integrate those
answers into you final project.
I have some great links below. You should visit each of
the links, which answer most of the questions below. You can also use
any other links that you find, but you must reference those links
in
your project.
•Focus Questions
The questions listed below AND contained in the website descriptions
are intended to get you STARTED. Your group
will split these questions up, so you will each have several questions
for which you are accountable. You need to let the teacher know which
questions each group member will cover. You don't have to do all of
the work for your questions, but you need to make sure that your
questions get answered well.
Group A
1. What is the definition of density?
2. How is density calculated? How could you alter the formula for
density to calculate mass or volume?
3. After completing one or more of the on-line quizzes below, create 6
problems that could be used to create a fourth quiz.
4. Why do swimmers float better in the ocean (or the Dead Sea) than
in freshwater? Be sure to THOROUGHLY explain this, including exactly
what
causes the differences and how it got this way.
Group B
1. What is the definition of density?
2. How is density calculated? How could you alter the formula for
density to calculate mass or volume?
3. After completing one or more of the on-line quizzes below, create 6
problems that could be used to create a fourth quiz.
4. What is Archimedes's principle? Explain it in your own words. How
does Archimedes's Principle relate to buoyancy and density?
Group C
1. What is the definition of density?
2. How is density calculated? How could you alter the formula for
density to calculate mass or volume?
3. After completing one or more of the on-line quizzes below, create 6
problems that could be used to create a fourth quiz.
4. Why would an engineer need to know about density/buoyancy? Try to
find at least three uses of density by people other than ship building
(outside of our class!).
Group D
1. What is the definition of density?
2. How is density calculated? How could you alter the formula for
density to calculate mass or volume?
3. After completing one or more of the on-line quizzes below, create 6
problems that could be used to create a fourth quiz.
4. What would happen to aquatic life if the density of solid water
(ice) was greater than the density of water (which is true of most
substances)? Make sure your explanation is thorough and specific.
Group E
1. What is the definition of density?
2. How is density calculated? How could you alter the formula for density to
calculate mass or volume?
3. After completing one or more of the on-line quizzes below, create 6 problems
that could be used to create a fourth quiz.
4. What is the fourth state of matter and why hasn't it always been studied?
Describe what molecules are doing in all four states of matter. Be specific and
include drawings or diagrams to help your audience understand.
Group F
1. What is the definition of density?
2. How is density calculated? How could you alter the formula for density to
calculate mass or volume?
3. After completing one or more of the on-line quizzes below, create 6 problems
that could be used to create a fourth quiz.
4. How do you determine if an object
will sink or float? How does a heavy, iron ship float?
•Links (I
would like you to visit all of these links...I think they're
pretty good!!)
IPPEX:
INTERACTIVE: Matter
An interactive introduction to the concept of density and its
determination. This site begins with a very nice overview of the
states of matter. You will also be able to complete a short lab in
which you test the buoyancy in a liquid whose density you control.
What relationship did you notice between density and an object's
ability to float in a liquid? What would be some consequences if ice
did NOT float in water? (Note: You will need the Shockwave plug-in
to
complete this activity.)
Weight Mass, Volume, Density
Sing this song. Go ahead, try it (just sing it, don't try to buy it in class).
Volume, Mass, and Density
This site offers a very basic review and practice for finding the
volume of an object, both by the displacement method and the L x W x H
calculation method. You are then led to determine the mass of the
object using a triple-beam balance. Finally, you calculate the density
to determine the identity of the substance. Which method of
determining volume would likely be the most accurate? Explain why you
think this is more accurate. During what situations will density NOT
be conclusive in determining the substance?
Archimedes's
Principle
Archimedes is probably the most famous scientist who ever studied
density and buoyancy. This website thoroughly covers his principle and
how to calculate if something will float. The second half of this site
contains some rather technical information; focus on the first half
and read through the second half.
Buoyancy
Another Archimedes site with a quicktime movie to show what Archimedes was talking about.
Buoyancy Flash Activity
You will examine whether the liquid in which an object
is placed affects the state of the object in the liquid. To examine
this, you can you use the following model. You will be experimenting
with three liquids each with a different density and many different
balls with different densities. See which ones float and which
ones sink in which liquid.
Density
and Buoyancy
Here's a nice youtube video on density and buoyancy. I think it will clear up some questions you didn't even know you had.
Buoyancy Brainteasers
OK. So you think you're getting this buoyancy stuff? This site offers
some basic information about buoyancy that you will want to read.
When
it all makes sense, try your hand at the three buoyancy brainteasers
(the last one even through me a curve!). You may want to click on
"Buoyancy Basics" before you begin for some more good information.
If you are floating on a raft in a swimming pool and you jump off the
raft and into the water, will the water level of the pool go up or
down (it would do one or the other, although probably not much!)? Why?
Trade Topics: How do ships float?
Here's a good answer to the question. Check it out.
On-Line Quiz from Quia
Quiz #1
So you still haven't had enough practice on density? Try your hand
at this interactive quiz. After you have completed this quiz, create
6 problems that could be used to create another quiz. Include two
questions
each for determining mass,
volume, and density when given the other two variables. Be sure to
proofread your questions, and include UNITS on all numbers!
Search Engines
Most of you are familiar with searching the net for information.
I've done nearly all of the searching for you (above). You will
only need to search the net when searching for COMMERCIAL APPLICATIONS
of density. Some of the search engines that I've used are Google,
Lycos, Alta Vista, and Metacrawler. Feel free to use any of these
in addition to your favorite search engine. Some keywords that
you may want to consider are density, buoyancy, Archimedes' Principle,
and flotation. (Hint: You may also want to add "education" to
each of these to narrow your searches somewhat.)
Credits and References
Background pattern used by permission.
Clipart (balance) used by courtesy of
ZDNet, a division of ZD Inc.
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