Classroom modifications for Rutgers Experiment
The following experiment is recommended for Grades 5-8. It is a simpler version of the Rutgers Experiment with instructions on how to measure the cell growth count. Directions for the chlorophyll absorption are the same as the Rutgers Experiment if you are able to secure a spectrophotometry from a neighboring hospital or university.

A. Classroom version of Rutgers Experiment
For those of us not fortunate enough to have at out fingertips all the wonderful equipment/supplies listed in this experiment, we, as teachers, know how to improvise! Follow the yellow brick road!

Order the following:

• A package of "Instant Ocean" or some comparable substance from your local pet store. If you want to work with fresh water, no problem. See the Materials (#8) and you will find the procedure for sterilizing fresh or salt water. Green algae: may be marine or freshwater depending upon your course objectives.
• Whirl packs

• Sterilize your medium. (Make sure you leave time between sterilizing the medium and the time when you add the green algae. Unless you are using an autoclave, some of the chemicals used in sterilizing will be harmful fatal- to your green algae.
• Add algae to nutrient medium sterilized fresh or marine medium.
• Leave the mixture in a place where it will receive maximum sunlight.
• At the end of one 24 hour period, use a pipette to check the numbers of algae. You may have a sufficient number to begin working with immediately, or you may have to take out a portion and concentrate them to obtain a sufficient number for counting.. OR you can just leave them for another day or two, and by taking samples at specific (your choice) intervals, determine when the number is right to work with. "Right to work with" = sufficient number to count easily, not too many algae because vast numbers will cause them to use available oxygen and die off before your experiment is over.

• Label Whirl Packs with permanent marking pens. (You will place the written part facing the bottom of your container kiddy pool, topless ice chest, or others after you have put the cultures in them.)
• Place container in a sunny spot.
• Fill container with water does not matter if it is marine or fresh it will not be mixing with your culture. It will used simply as a flotation device for your Whirl Packs filled with cultures.
• Fill Whirl Packs approximately half full of culture. (Make sure they have oxygen.)
• Place Whirl Packs in kitty pool, etc., with writing on the packs facing bottom of the container. This eliminates one variable of something interfering with amount of sunlight available to each Whirl Pack.
• Check the next day, make your count, and record your results. You will see a pattern develop over time. If your experiment runs long enough you just may find that their environment crashes and dies. What a wonderful way to get over to your students the concept of sustainability!

B. How to make a simplified version of a hemocytometer for the classroom version of the Rutgers Experiment and how to measure its cell growth.

	Use an ordinary slide. Using plastic cover slips, cut four strips from this cover slip.
	To make a chamber, glue (using clear fingernail polish) the four strips onto the slide with the smooth edges facing inward.
	Fill the chamber with a well mixed sample of phytoplankton. Cover with a cover slip (make sure it is the same dimensions of the one you used to make the chamber).

How to measure cell growth using simplified version of the hemocytometer.
1. Measure length and width of the chamber and obtain the depth of the chamber from the cover slip box.
2. Multiply L x W x H to obtain volume of your self-constructed counting chamber.
3. Fill the chamber with a well mixed sample of phytoplankton.
4. Cover with a cover slip (make sure it is the same dimensions of the one you used to make the chamber).
5. Count the number of cells per chamber and apply your own factor.
6. An alternate method is to count the number of cells per chamber and record your count as "cells per chamber." This method is crude but will work to show the increase in number of cells over time.

C. Spectrophotometry Procedures for chlorophyll absorption in the classroom

Extension: Using different kinds of sunscreens
1. Do the classroom version of the Rutgers Experiment.
2. Apply sunscreen on both sides of the Whil Pak.
3. Take cell growth count and compare results from the different brands.

Extension: Demonstration of chlorophyll fluorescence
Purpose: To see how photons not used during photosythesis are released as fluorescence in green plants.
1. Measure 500 grams of spinach leaves chopped into small pieces and put into a tall glass jar(1 liter), 3/4 filled with rubbing alcohol.
2. Let stand in the freezer for 2-3 days.
3. The liquid will change to a dark green fluorescence.
4. Shine the flashlight on one side of the container. The dark red fluoresence will be observed on the same side.

What is happening: When chlorophyll captures light energy(photons), it releases the energy through two channels.  One way it is releasing energy is through photosynthesis and the other is through fluorescense.If photosynthesis occurs under optimal environmental conditions there will be more photosynthesis and less fluorescence. However if the  environmental conditions are not optimal as too much radiation, too little nutrients or too much carbon then there will be more fluorescence and less photosynthesis.

Extension: Investigating the foods you eat to determine what algae derivatives they contain.

http://seawifs.gsfc.nasa.gov/OCEAN_PLANET/HTML/education_lesson1.html
http://seawifs.gsfc.nasa.gov/OCEAN_PLANET/HTML/education_lesson1.html

Rutgers Experiment	Main Page	Materials	Websites
Standards, Inquiry Assessment	Glossary	Mahalo (Acknowledgements)	Ask an Expert

 

b

The Woodrow Wilson National Fellowship Foundation CN 5281, Princeton NJ 08543-5281 - Tel:(609)452-7007 - Fax:(609)452-0066 Technical contact: lpt@woodrow.org