The purpose is to compare the fat content of different grades of ground beef. Too much fat in our diet may be unhealthy, especially if we do not get enough exercise. We should be aware of fat in the foods we consume, so we can make healthier choices when purchasing such items as ground beef (lean or extra lean) and milk (whole or skim).
Fats are substances found in animals and some vegetables. Fats are used by the body for energy. When the body's demand for heat increases, as it does during the winter or in cold climates, more fat is required by the body. Eskimos, for example, consume a great amount of fat in their diet. When more fat is eaten than the body currently needs for growth or energy, the fat is stored in tissues.
Fats are made up of carbon, hydrogen, and other elements. The carbon and hydrogen give fats their capability to give off huge amounts of heat. Have you ever cooked chicken still in its skin on a barbecue grill? If so, you probably noticed that when the chicken fat fell into the fire, it caused a flare-up of flames.
Hypothesize there is significantly more fat in standard ground beef than in ground beef labeled extra lean.
- Adult supervision (exercise caution around a hot stove)
- Package of ground beef
- Package of lean ground beef
- Package of extra lean ground beef
- Small cooking pot
- Kitchen gram-weight scale
- Three paper plates
- Measuring cup
- Clock or watch
- Pencil and paper
- Use of a kitchen stove
- Use of a refrigerator
Fats can be liquefied by heat. When you fry bacon in a pan, you have no doubt noticed all the fat that appears in the pan. Heating bacon in a microwave oven yields the same result.
The mass of each meat patty, the cooking time, and the amount of water used for boiling are all constant. The fat grade of ground beef is the variable.
Obtain three small packages of ground beef, one simply labeled "ground beef," one labeled "lean," and one labeled "extra lean."
From each package of meat, mold a hamburger-shaped patty. Use a small kitchen scale to make sure each patty weighs the same.
Place the first patty in a pot and put it on a stove burner. Add one or two cups of water as needed to completely cover the patty. Record the amount of water added.
Note the time on a clock or watch. Turn the burner on its highest heat setting. Bring the water to a boil. Carefully break up the patty into small pieces as it is boiling, so the boiling water can reach all parts of the meat. Use extreme caution when working around boiling water. The heat will extract the fat from the meat, and the fat will rise to the top of the water.
After several minutes of boiling, turn the burner off and note how much time has passed on the clock.
Weigh a paper plate on a kitchen gram weight scale and record the weight.
Place the pot and its contents in a refrigerator. As the fat cools, it will coagulate (change into a thickening mass). After the coagulated fat has cooled for several hours, scoop it off the top with a spoon and place it on the paper plate. When all the fat is on the plate, weigh it. Subtract the weight of the paper plate (the tare weight) to determine the weight of the collected fat.
Clean out the pot and repeat the process for each of the remaining two grades of ground beef. Use an equal amount of water to boil each patty and boil each for the same length of time.
Compare the weights of the fat collected from each grade of meat. Is the amount of fat significantly less in the extra lean grade than the other grades?
You know the original weight of the patties and the weight of the collected fat. What percentage of each patty was fat? Divide the fat weight by the patty weight and multiply by 100.
Write down the results of your experiment. Document all observations and data collected.
Come to a conclusion as to whether or not your hypothesis was correct.
- Compare the fat content in meat mixtures (beef and pork are often sold together).
- Ground beef that contains more fat may not be as healthy, but is it tastier?