The Marathon Battery Story printable pdf download

The Marathon Battery Story

Name ______________________

Date ___________

The Marathon Battery Story

What does one part per million look like?

Serial Dilution Activity

To help you visualize the scale of parts per million, you will dilute food coloring with water until you

have a liquid that is one part per million food coloring. Note that1 ppm = 1:1,000,000.

Materials: Spot plate with at least seven wells; dark food coloring, color pencil of the same color; water;

dropper; grease pencil

Procedure:

Set up the food coloring:

a) Label seven wells on your spot plate from #1 to #7 with the grease pencil.

b) Put 10 drops of food coloring in well #1.

c) Put 9 drops of water in each of the other wells, #2 – #7.

d) Color well #1 below to show 100% strength food coloring.

Conduct the serial dilutions:

e) To begin the serial dilutions, use the dropper to take one drop of food coloring from well #1 and add it to

well #2. Stir gently. In #2, you now have a liquid is 10% food coloring. One way to represent this is to

write the ratio 1:10, or one drop of food coloring to 10 drops of liquid. Color well #2 to show 10% food

coloring.

f) Next use the dropper to put one drop from #2 (not from #1) into well #3. What percent of the solution is

food coloring? ____________ What is the ratio of food coloring to liquid in #3? ____________ Record

the ratio below and color well #3.

g) Continue the serial dilution in sequence, always adding one drop from the previous well, until you have

added one drop of #6 to #7. Record the ratio of food coloring to liquid for each dilution and shade in the

circle to match the color of the liquid in each well.

Student Worksheet

Marathon Battery: Serial Dilutions

The Marathon Battery Story