HOW TO WHIP CREAM
What is whipped cream? It's a foam. "That's cool," you might say, "but what exactly is a foam?"
A foam is a liquid that is mixed with air. You see foam at the seashore, when waves crash against the beach. The foam forms when seawater mixes with air.
If your dad or brother shaves with a manual razor instead of an electric one, he might use shaving cream, another kind of foam. Shaving cream is a soap or a detergent that gives a high-volume, very light, white foam when mixed with air. It almost looks good enough to eat, but you'll be sorry if you taste it!
Whipped cream is a mixture of cream, sugar, and a little vanilla extract. First, the cream is whipped or beaten in the presence of air (or nitrous oxide). The cream has enough structural integrity (meaning it is strong enough) to hold trapped air for a while. When the cream forms peaks, it is ready. The other ingredients are carefully folded in to create a tasty treat. Look for whipped toppings in the refrigerated or freezer sections of your supermarket. Read the contents. REDDI-WHIP™ is whipped cream in a can. Many other whipped toppings contain little or no cream.
EXPERIMENT 15
Materials
½ pint (240 mL) whipping cream
A small mixing bowl that has been stored in the freezer for about 1 hour
An electric mixer
A watch (a stopwatch would be great)
Sugar
Vanilla extract
A spoon
Two small plates
A can of REDDI-WHIP
A refrigerator
Procedure
1. Pour the cream into the bowl.
2. Place the mixer in the bowl.
3. Start the watch and turn on the mixer. Begin at a low setting, and slowly increase the speed to the highest setting.
4. When the cream begins to stiffen and forms peaks, look at the watch. Record the time. How long did it take to whip the cream?
5. Remove the mixer and delicately fold in sugar until you think the whipped cream is just sweet enough. Add a small amount of vanilla extract. Now you have a mass of tantalizing, taste-tempting, majestic whipped cream.
5. Using a spoon, place a dollop of whipped cream on a small plate.
6. Squirt about the same amount of REDDI-WHIP onto another small plate.
7. Put both plates in the refrigerator. Check them every hour or so. Which whipped cream starts to "melt" first?
Results
This "melting" is called weepin The cream that weeps first has less structural integrity. If you prepare desserts that are topped with whipped cream ahead of time, you should remember that the cream will weep. If you don't, you might end u with a dessert covered with globs of yucky-looking, watery white stuff. Read the ingredients of the REDDI-WHIP. Compare these ingredients to the ingredients in the whipped cream that what are they? You made. Are there differences? If, so what are they??
BEFORE IT'S BUTTER
Butter, like cream, is a byproduct of milk. It is made of cream that has been churned. Churning is a process in which the cream is agitated (vibrated, mixed, or shaken) vigorously.
During the churning process, most—if not all of the fat blends together in large clumps. According to a law passed in 1923, butter must contain at least 80 percent milk fat. It may also contain salt and/or artificial coloring.
EXPERIMENT 16
Materials
A 12-ounce (360 mL) jar with a screw-on cap and a rubber ring on the inside
½ pint (240 mL) heavy cream
A friend
Procedure
1. Pour the cream into the jar.
2. Screw the lid on tightly.
3. Shake the jar vigorously.
4. When you get tired, have your friend take over. When your friend gets tired, it's your turn again. In a few minutes, the cream should start to look like foam, sort of like whipped cream. Keep on shaking!
5. After a while, you'll see little clumps forming. Continue shaking and shaking! (Now you know why you need a friend's help.)
Results
The clumps you see are small pieces of butter. When the clumps are about the size of grains of rice, your butter is ready. To recover the butter, pour off the liquid buttermilk and then add some cold water to the jar. Rinse the butter off the sides, and carefully pour off the water. Collect all the clumps of butter in a dish and mash them together. Spread some on bread and taste some really fresh butter.
I SCREAM, YOU SCREAM,
WE ALL SCREAM FOR ICE CREAM
When I was a kid, I screamed for ice cream once in a while, but most of the time I whined.
Maaaaaaaaaa!!!! I waaaaannnnnt ice creeeeeeam. Come on, maaaaaaaaaaaaaaaa! Please, maaaaaaaaaaaa. I promise I'll be goooooooooood!!!!
Ice cream is one of my favorite—if not my absolute favorite science— related supermarket items.
Ben & Jerry's™, Haagen-Dazs™, Sealtest™, Breyer's™, and a whole lot of other folks prepare one of America's favorite treats. Part of the reason they can make ice cream so delicious is because they know something about science.
At one time, ice cream was eaten only by royalty. Not only was no one else allowed to eat it, but very few people knew how to make it. They didn't know the formula. Yeah, that's right formula. Lots of foods are made from secret (and not so secret) formulas. Have you ever looked through a cookbook?
It's loaded with formulas called recipes. Following a recipe is very similar to performing the steps of a chemistry experiment. The only difference is that you shouldn't eat the final product of a chemistry experiment.
You can make ice cream at home. It's easy. Here's a recipe, I mean formula, that should lead to success.
EXPERIMENT 17
Materials
1 cup (240 mL) heavy cream
¼ cup (60 mL) sugar
½ teaspoon (2.5 mL) vanilla extract
A large mixing bowl
A 4- or 6-ounce (1 25- or 180-mL) paper cup
A Styrofoam soup container (pint or quart-size)
Crushed ice
¼ cup (60 mL) kosher salt (or other coarse salt)
Two clean teaspoons
Procedure
CAUTION: Ask an adult for permission to perform this experiment. It should be done in a sink.
1. Combine the cream, sugar, and vanilla extract in the mixing bowl. Stir well.
2. Pour this mixture into the paper cup until it is about two-thirds full.
3. Fill the Styrofoam container halfway with the crushed ice, and add a little salt.
4. Mix the ice and the salt with a spoon to create a slushy mixture.
5. Hollow out the center of the slushy mixture with the spoon.
6. Place the paper cup into the hollow area. Do not let any ice slush fall into the cream-sugar mixture inside the cup. The level of the slushy ice outside the cup should be at least as high as the cream-sugar mixture inside the cup.
7. Using the other spoon, gently stir the cream-sugar mixture. Use the edge of the spoon to scrape the hardened ice cream off the walls and bottom of the cup. After 15 to 20 minutes, the ice cream-oops! I mean your experiment should be ready to undergo the taste test.
Results
Water from the tap freezes at 32˚ F (0˚ C). The cream-sugar mixture freezes at 26 to 24˚ F (-3 to -4˚ C). To make ice cream, you must find a way to lower the temperature of the ice a little bit. Adding a little salt does the trick.
Saltwater freezes at a lower temperature than tap water. Adding salt to the ice makes it possible to lower the temperature of the slushy ice-salt mixture just enough to freeze the cream-sugar mixture.
Appendix
English and Metric Measurements
ENGLISH UNITS OF LENGTH
1 foot = 12 inches
1 yard = 3 feet
1 mile = 1,760 yards
1 mile = 5,280 feet
METRIC UNITS OF LENGTH
1 millimeter (mm) = 1/1,000 meter
1 centimeter (cm) = 1/100 meter
1 decimeter (dm) = 1/
10 meter
1 kilometer (km) = 1000 meters
CONVERSION TABLE FOR UNITS OF LENGTH
English to Metric
1 inch = 2.540 centimeters
1 foot = 0.305 meter
1 yard = 0.914 meter
1 mile = 1.609 kilometers
Metric to English
1 centimeter = 0.39 inch
1 meter = 39.37 inches = 3.28 feet = 1.094 yards
1 kilometer = 0.62 mile
ENGLISH UNITS OF AREA
1 square foot = 144 square inches
1 square yard = 9 square feet
METRIC UNITS OF AREA
1 square centimeter (sq cm) = 1/10,000 square meter
1 square decimeter (sq dm) = 1/100 square meter
CONVERSION TABLE FOR UNITS OF AREA
English to Metric
1 square inch = 6.451 square centimeters
1 square foot = 0.093 square meter
1 square yard = 0.835 square meter
1 square mile = 2.588 square kilometers
Metric to English
1 square centimeter = 0.152 square inch
1 square kilometer = 0.384 square mile
Glossary
absorb to take up another kind of matter, as when sugar (a solid) dissolves in water (a liquid).
adhesion the sticking together of two surfaces.
aerosol a suspension of fine solid or liquid particles in a gas.
buoyancy the tendency of a body to float in water.
capillary a small hollow tube that carries fluids in plants and animals
centrifuge a machine that uses a force created by spinning motion to separate substances with different densities.
churn (verb) to agitate. In the case of milk, churning separates the oily globules (butter) from the watery liquid.
cohesion the tendency of a material to hold together as a result of attractive forces between molecules.
concave rounded inward. A bowl has a concave shape.
convex rounded outward. A globe is convex.
density the ratio or fraction of the mass of a material compared to its volume; the quantity of substance per unit of space.
displace to move an object to a new position.
distillation the process of purifying water or another liquid by heating it until it boils and then cooling it until it condenses.
elastic capable of being deformed (stretched or squeezed) and then returning to its original shape. A rubber band is elastic.
evaporation the process that occurs when a liquid turns into a gas.
filler a substance added to a product to increase its bulk.
homogenize to blend two or more substances into a uniform mixture.
hydrophilic a term used in physics and chemistry when something readily forms a solution with water.
hydrophobic a term used in physics and chemistry when something does not mix easily with water.
hygroscopic readily taking up moisture.
meniscus the curved shape that forms at the surface of a liquid held in a container.
ozone layer the layer of ozone molecules in the upper region of Earth's atmosphere.
pasteurize to destroy bacteria and other microorganisms in milk.
pathogenic disease-causing, such as germs, bacteria, or viruses.
pressure the action of a force against an opposing force.
propellant a gas kept under pressure in a bottle or a can. It is used to expel the product that is in the container.
ratio the relationship in quantity, amount, or size between two or more things.
saturate to dissolve the maximum amount of one substance that can be dissolved in another.
solute a substance dissolved in another material.
solution a homogeneous mixture of two or more substances.
surfactant a substance, like soap or detergent, capable of acting on two types of substances simultaneously.
Resources
BOOKS
Gonnick, Larry. The Cartoon Guide to Physics. HarperCollins, New York, 1990.
Macauley, David. The Way Things Work. Houghton Mifflin, Boston, 1988.
McGraw Hill Concise Encyclopedia of Science and Technology. McGraw Hill, New York, 1984.
Walker, Jearl. The Flying Circus of Physics. John Wiley, New York, 1977.
INTERNET SITES
Due to the changeable nature of the Internet, sites appear and disappear very quickly. These resources offered useful information at the time of publication.
Dr. Internet is a guide to science experiments and science sites on the Internet.
http://ipl.sils.umich.edu/youth/Drlnternet/
The Fruit and Vegetable Nutrition Center has all kinds of interesting information about fruits and vegetables-popular supermarket items. The site is sponsored by Dole Food Co.
http://www.dole5aday.com/NUTINFO.html
Helping Your Child Learn Science is an online book full of activities and experiments that can be done at home.
http://www.ed.gov/pubs/parents/Science/index.htmI ICE Picks is an online guide to science activity books.
http:// jchemed.chem.wisc.edu/-icehe-Pickshp-titleindex.html
The Super Science site provides help for scientific experiments and has tips for experiments with everyday things.
http://www.superscience.com/home.html
Yahooligans! Science and Oddities is a great place to search for additional science sites.
http://www.yahooligans.com/Science~and~Oddities/
If you visit the YES Mag: Canada's Online Science Magazine site, you can find out about science news, projects, and more.
http://www.islandnet.com/-yesmag/homepage.html
About the Author
Bob Friedhoffer has a master's degree in the history and philosophy of science from the City University of New York. Also known as the Madman of Magic, he has been performing for children and young adults for 30 years. He lectures frequently on science and magic. His entertaining approach to science can be found in more than a dozen books written for Franklin Watts. Several of these books have won awards. Bob lives with his wife and daughter in New York City.
Science Lab in the Supermarket (Illustrated) Page 5