The purpose of this experiment was to compare the dehydration rate of
plant and animal cells exposed to anhydrous ammonia.
I became interested in this idea when a Yakima County Sheriff’s
Department drug detective showed me money that had been dehydrated by
anhydrous ammonia.
The information gained from this experiment could help people preserve
food. Also it will help with food transportation because dehydration
cuts down the weight by taking away the moisture. This could also
help space travel.
My hypothesis was that the animal cells would dehydrate more completely
and faster than the plant cells.
I based my hypothesis on an Internet site of Florida State University
that said, “plant cells have a rigid wall surrounding the plasma
membrane” it also said that “animal cells don’t have a cell wall.” This
means that the plant cell has a harder outside with the rigid cell wall
and the animal cell doesn’t, so it should be easier to take all the
moisture out.
The constants in this study were:
- Anhydrous ammonia
- Temperature
- Size
- Time
- Brand of plastic sandwich bag
The manipulated variable was the different types of food being
dehydrated.
The responding variable was the weight of the cells after being
dehydrated.
To measure the responding variable I used a digital scale calibrated in
grams.
| QUANTITY |
ITEM DESCRIPTION |
| 2 |
Steaks |
| 2 |
Pork chops |
| 2 |
Chickens |
| 2 |
Apples |
| 2 |
Oranges |
| 2 |
Celery |
| 2 |
Broccoli |
| 1 |
Triple Beam Balance |
| 1 |
Ruler |
| 1 |
Knife |
| 3 Pints |
Anhydrous Ammonia |
| 1 Box |
Plastic Sandwich Bags |
| 1 |
Sink |
| 1 |
Wooden Spoon |
| 1 |
Pot |
| 1 |
Strainer |
| 1 |
Tongs |
PROCEDURES
1. Prepare foods for drying
a) Clean and dry
b) Slice food into 2 by 2 by 8 cm
strips
c) Store in a sandwich bag and
record weight
d) Repeat until all food has been
weighed
e) For the orange take off peel
2. Find a well ventilated area
3. Put 250ml of anhydrous ammonia into the metal pot
4. Put the three pieces of beef into the same pot
5. Stir and mix the food and ammonia around with the wooden spoon
6. Take out using the tongs and/or wooden spoon
7. Put the dehydrated food back in plastic bag
8. Get new anhydrous ammonia (250ml)
9. Repeat steps 4-8 using the other foods
10. Continue until all food has been dehydrated
11. Dispose all anhydrous ammonia in a well ventilated area
12. Record new weights
The original purpose of this experiment was to compare the dehydration
rate of plant and animal cells exposed to anhydrous ammonia.
The results of the experiment were that the anhydrous ammonia
dehydrated the animal cells the most with a total of 13.75 and the
plant cells the least with a total of 12.25.
See my table and graph.
My hypothesis was that the animal cells would dehydrate more completely
and faster than the plant cells.
The results indicate that this hypothesis should be accepted.
Because of the results of this experiment, I wonder if different types
of plant and animal products would dehydrate in a similar manner.
If I were to conduct this project again I would have conducted more
trials and would have used more types of food.
Introduction
Anhydrous ammonia is used for a lot of different purposes, including
dehydrating items like food. Dehydration keeps items fresh, save
space, and doesn’t require refrigeration to preserve food. Plant
and
animal cells are similar in some ways but different in their cell wall
structure. This could affect how easily the cells can be
dehydrated.
Ammonia
The formula for ammonia is NH3. Ammonia is a compound of nitrogen
and
hydrogen. Ammonia is a non-toxic, colorless gas. It is known for its
irritating odor. It is extremely soluble in water. If one is going to
breathe in ammonia make sure it is heavily diluted. If mixed with metal
it makes a compound called ammines. During evaporation 1 gram of
anhydrous ammonia requires 327 calories of heat. Ammonia is used in a
lot of things.
Uses
Ammonia with more nitrogen is used for crop production. Ammonia also
makes alkaline. Ammonium hydroxide is used in house cleaners and
artificial fertilizers. It is used in dynamite, TNT, and other
explosives. It is used to dye and scour wool, to make nylon, cotton; it
is also in some vitamins, plastics, drugs, and chemicals. Anhydrous
ammonia is also used for a lot of useful things.
Anhydrous Ammonia
Anhydrous means without water so when it touches something with water
in it; it takes out all the moisture. Anhydrous ammonia is 82%
nitrogen. It has to be handled by workers who have been educated on how
to correctly use this dangerous chemical. The liquid state of the
anhydrous ammonia has to be stored in tanks. The tanks have to be able
to stand pressures of at least 250 PSI (pounds per square inch). If a
valve is opened for the liquid to get out it turns it into the gas and
can get into your body. Anhydrous ammonia is used for quite a few
things.
Uses
Anhydrous ammonia is used in a lot of fertilizers and ice packs. If
there is a mold growth in grain with high moisture, then some people
put anhydrous ammonia on it. All the moisture will be removed and the
mold will go away without the moisture. It is also used to keep crops
cold while they are in storage getting ready to ship to stores. One
reason anhydrous ammonia is used is for dehydration, which is a way of
preserving food.
Preservation
Today someone can go to the store and pick up almost any kind of food
that is preserved in some kind of package or container. Before
preserving food was an option the food someone could get from the store
had to either be fresh or there was probably something wrong with it
because bacteria had most likely attacked it. The three main ways of
preserving are freezing, canning, and dehydrating or drying.
Dehydration and Drying
Drying has been used for a very long time. Some of the reasons we have
dehydrating and drying is to keep food items fresh, to save space, and
dried food doesn’t have to be refrigerated.
Cells
Most cells are so small you can only see them under a microscope. All
cells have a specific job to do. Cells are like people with some
things, like they need oxygen to live and need to get rid of the carbon
dioxide that comes in with the air. All cells will eventually die too.
There is a membrane outside every cell. The nucleus is the thing that
controls genetic program. Outside the nucleus is the cytoplasm.
DNA
stands for Deoxyribonucleic Acid. All plants, animals, and humans have
lots and lots of cells.
Plant Cells
Plant cells are unique among eukaryotes. Chlorophyll gives plants their
green color. It also makes it so the plants use sunlight to turn water
and carbon dioxide into sugar and carbohydrates, which they use for
fuel. Plant cells have a protective cell wall like prokaryotic
ancestors. Plant cells don’t have centrioles, lysosmes, cilia or
flagella unlike animal cells. They do have chloroplast, central
vacuole, plasmodesmata, and a rigid cell wall. There are about
250,000
species of plants. A small percent of plants are used for human needs,
such as food, shelter, medicine, and fiber. Plants are the basis for
the food web and ecosystem. Without plants no animals or human would
have evolved. Animals also have a lot of cells.
Animal Cells
Animal cells do not have a cell wall. An animal cell’s nucleus and
organelles have a membrane surrounding them. Animals have a greater
variety of different cell types, organs, and tissues. All organisms in
animals are incredibly different. Three quarters of the earth species
are animals. Plants can make their own food but animals are unable to
produce their own food so they rely on plants for a lot of things.
Summary
Dehydration has been used for centuries to preserve items, especially
food, and to save space. Plant and animal cells are similar but
different in their cell wall structure, which probably affects how
easily the cells can be dehydrated. Anhydrous ammonia is used for
several industrial purposes, often to remove water from items.
With
care it could be used for dehydrating food.
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Armbruster, David C. “Ammonia.” World Book Encyclopedia. 1995.
Beck, Laurence H. “Dehydration.” World Book Encyclopedia. 1998.
Davidson, Michael W. “Animal Cell Structure.”
http://micro.magnet.fsu.edu/cells/animalcell.html.
Davidson, Michael W. “Plant Cell Structure.”
http://micro.magnet.fsu.edu/cells/plantcell.html.
“Dehydration.” http://quickcare.org/gast/dehydrate.html.
Johnson, Taylor J. “Anhydrous Ammonia,” World Book Encyclopedia.
1999.
Knepp, Brian. "Nitrogen and Phosphorus." Grolier Education, 1996.
Shutske, John M. “Using Anhydrous
Ammonia Safely on the Farm.”
http://www.extension.umn.edu/distribution/cropsystems/DC2326.
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I would like to thank the following people for helping make my project
possible:
- My parents for buying the materials needed for my
experiment
- Mr. Newkirk for helping me through my project
- Mrs. Helms for answering my questions
- My friend Baylee for encouraging me to keep persevering
when I thought my project got too hard
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