Baffling Beaters
FOOD SCIENCE EXPERIMENT: EGGS
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The following experiment is designed to supplement activities in already
existing food and nutrition projects. First read the section "Caution-Be
Science Wise" and then help 4-H members work through the experiment.
CAUTION - BE SCIENCE WISE!
Before you begin any science experiment, you should always follow these basic
rules:
1. Be sure to read ALL directions before starting the experiments.
2. In many experiments, a "control" is used. The control is the standard
against which you compare the experimental food.
3. When doing the experiments, keep everything the same as the control except
for the one thing the directions say to change. Use the same size pans,
the same type of bowls and the same mixing speeds. Be sure that just ONE
thing changes each time.
4. Be sure to label each food when conducting these experiments. Use a piece
of masking tape, a marking pencil, a crayon or anything that will help you
remember which food is which. In some experiments, you'll have no trouble
telling the foods apart. In others, the foods may look the same.
5. The experimental food is not meant to be perfect. Since you are purposely
doing something wrong, you can't expect it to be perfect! So it's all
right when something turns out "bad." That's what is SUPPOSED to happen.
6. Not all experiments in food science yield products that can be eaten.
NEVER SAMPLE PRODUCTS IN AN EXPERIMENT UNLESS YOUR LEADER SAYS THEY ARE
SAFE TO EAT.
7. Records are an important part of any scientific project. You should write
down what happens in each experiment. Experiments may not turn out exactly
the same every time. Recording your results will help you and others who
may try to repeat your experiment.
BAFFLING BEATERS
INTRODUCTION
Egg whites are made up of water, protein, and small amounts of minerals and
sugars. When egg whites are beaten, air gets added. The air bubbles are then
surrounded by the egg white protein, causing the egg white foam to become
stiff and stable. When an acid such as cream of tartar is added to an egg
white foam, the foam becomes even more stable.
This experiment will help you understand this baffling mystery!
INGREDIENTS
2 egg whites from equal-size eggs at room temperature
1/8 teaspoon cream of tartar
EQUIPMENT
2 mixing bowls, same size
Electric mixer or rotary beater
2 clear glasses (10 ounces or larger), same size
PROCEDURE
1. You will need to record the exact time as you begin to beat each egg white.
Record the time on the chart.
2. In a mixing bowl, beat one egg white with the electric mixer or rotary
beater until stiff peaks form when the beaters are lifted out of the egg
white. Record the minutes and seconds this took. Keep this egg white for
comparison.
3. As you begin to beat the second egg white, record the time. Beat the
second egg white in the remaining bowl until it is foamy. Add the cream of
tartar and immediately start beating again at the same speed until stiff
peaks form. Record the total beating time.
4. Pour each beaten egg white into a clear glass. Label the glasses "with
cream of tartar" and "without cream of tartar." Let the egg whites stand
for one hour.
5. Pour off the accumulated liquid and measure the liquid in the measuring
cup. Record the amount.
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Egg White without Egg White with
Cream of Tartar Cream of Tartar
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Starting time
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Total amount of beating time
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Amount of accumulated liquid
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6. See if you can answer the following questions based on what you observed:
* Did it take longer to beat to stiff peaks the egg white with cream of
tartar or the egg white without cream of tartar?
* Which egg white lost LESS liquid after one hour?
* What can you conclude about how cream of tartar affects egg whites when
beaten?
* Why would you want egg whites to be stable after beating?
EXPLANATION
The white of an egg is approximately 10 percent protein and 85 percent water.
By beating air into an egg white foam, the protein coats the air bubbles and
holds in the water. When an acid like cream of tartar is added to the foam,
this helps the protein to continue to coat the air bubbles and holds in the
water. Adding an acid increases the time it takes to beat the egg white foam
to stiff peaks but makes the foam more stable and therefore less likely to
lose water.
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AN "EGGASPERATING" SITUATION
Help! Your little brother (or sister) has mixed udp the uncooked eggs with
the hard-cooked eggs you had prepared for egg salad. What should you do?
Spin the eggs on their pointed end. A hard-cooked egg will spin like a top.
An uncooked egg will fall over. Try it and see!
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SOURCE: Food Mysteries, Michigan State University
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Updated 8/15/05