Name _______________________ Date _________
Liquid Layers Challenge
Challenge: Can you determine the density of each liquid, and create a
rainbow in a straw?
Background:
Mass and volume are properties of matter.
Density is the ratio of mass and volume. The density of a specific kind of matter
helps to identify it and distinguish it from other kinds of matter.
The formula used to calculate density is:
Density = Mass ÷ Volume (D=M/V)
Part One: Determine the density of each liquid.
Materials: Liquids, beaker/graduated cylinder, scale/balance beam,
calculator
Procedure:
1.
2.
3.
4.
Use the scale to find the mass of your empty container. Record.
Add 10 ml of a liquid.
Find the mass of the container + the liquid. Record.
Subtract the mass of the container from the mass of the container + the
liquid. Record.
5. Calculate density. D = M/V
6. Repeat for all liquids.
Liquid
Liquid
1
Liquid
2
Liquid
3
Liquid
4
Liquid
5
Mass of
Container
(g)
Mass of
Container
+ liquid (g)
Mass of
Liquid
(g)
Volume
(mL)
Density
(g/cm3)
Order
(least
density to
greatest)
Name _______________________ Date _________
Part Two: Creating a rainbow in a straw.
Using what you know about density and the information you’ve gathered from the
mystery liquids, you will create a liquid rainbow in a straw.
Materials: Liquids, beaker/graduated cylinder, scale/balance beam,
calculator
Procedure:
1. Double check the “Order” column of your chart. Be sure the liquid with the
lowest density is #1 and the liquid with the highest density is #5.
2. Your goal is to make a “liquid rainbow” in your straw. Using 1-2 drops of food
coloring, color each of the liquids a different color of the rainbow.
a. (HINT: The liquid with the lowest density should be colored with the
first color of the rainbow!)
3. Place one end of the straw into the least-dense liquid – about an inch – and
place your index finger over the other end of the straw. Pull the straw out of
the liquid and notice how the liquid stays in the straw. If you release your
finger, the liquid will fall out of the straw. Make sure you can do this well
before moving onto the next step.
4. Once you have the first liquid in your straw, place the straw into the 2nd
densest liquid (about an inch below the surface).Slowly release your finger
from the top of the straw and the second liquid will push the other layer up.
Press your finger firmly on top of the straw and remove the straw. Don’t
release your finger from the top of the straw – you’ll have to start all over
again!
5. Lower the straw with the two colored layers into the third densest liquid
about an inch lower than the second liquid in the straw. Slowly release
pressure with your finger and the liquid will push the other layers up about
an inch. Seal the top of the straw with your index finger and move onto the
next liquid.
6. Continue with this until you have 5 colors of the rainbow (in order!) in your
straw.
7. Show an adult your straw for an initial on your paper.
8. When you are ready, release your finger from the straw over a sink or empty
cup. Give yourself a pat on the back. Good work.
Teacher Signature:
Rainbow in a straw complete & correct: __________________________
Name _______________________ Date _________
Analysis:
1. Why do the liquids settle in this order? (Explain using complete sentences.)
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2. Draw a diagram of your straw, labeling the liquids in the correct order. Use
color in your diagram.
3. In 5-8 sentences describe density, how it works, and what you learned about
density from this challenge. Give examples to support your claims. (You may
use additional paper, if needed. Staple extra paper to this sheet.)
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