Potato Decibel Lab
Else Gerber, Zoe Wheeler, Mari Torii-Karch, and Jonathan Vonderlage
Period 6
Research Question:
How does the initial temperature of a potato affect the volume in decibels reached when it’s cooking?
Introduction:
The goal of this lab was to see if there was a measurable difference in the decibels recorded when placing potatoes of different starting temperatures into hot oil. The previous knowledge brought into this lad was that each group member had personal experience with the sound associated with frying food that was initially colder that the hot oil. It was suspected that there would be a correlation between how cold the potato was and how loud it would be when a cold potato met hot oil. Temperature is the average kinetic energy of the molecules in an object, where sound is vibrations that travel through the air in the form of sound waves. Decibels are the units that measure the intensity or power level of the sound. Finally, sublimation is when a substance skips the liquid phase and goes straight from ice to gas. The purpose of this lab was to determine whether colder things made more noise and whether or not it corresponded to how cooked it became.
Variables:
Independent Variable: Initial temperature of the potatoes in degrees Fahrenheit
Dependent Variable: Volume, in decibels
Controlled variables:
Original oil temperature
Time oil was on hot plate
Time of the potatoes were cooking before the decibels were measured
All in the same day
Amount of oil
Beaker size
Size of potato
Temperature of hot plate
Type of potato
The decibels app
Hypothesis:
The colder the starting temperature of the potato, the louder the sizzling will be. This is predicted because the temperature of the water in the potato will be at a greater contrast to the hot oil and the movement of molecules would be more rapid, thus generating a greater decibel level.
Materials:
9 pieces of potato: 3 frozen, 3 refrigerated, 3 at room temp, size range: 1 ½ x 1 x 1 4/10 – 2 x 1 ½ x -1 ½ cm
Meat thermometer to measure the potatoes internal temperature
Beaker
Canola oil (50 milliliters)
Thermometer to measure temperature of oil
Tongs
Hot plate
Graduated cylinder
Decibel measurement app: Decibel X
Procedure:
Separate the potatoes into nine pieces
Put three potatoes into three different bags
Set one bag in the refrigerator, one in the freezer, and one out on the counter and leave all overnight.
The next day, using a graduated cylinder, measure 50 milliliters of canola oil and put into a medium-sized beaker
Pour the oil into the beaker and set it onto the hot plate
Put hot plate to 5 and wait 5 minutes for the oil to heat up.
Make sure the oil has reached a temperature of 90 degrees Celcius or above.
Measure the temperature of the set of potatoes chosen using the meat thermometer
Using the decibels app, measure the starting sound level of the room
Put in one room temperature potato.
After 15 seconds, measure the decibels
Repeat steps 8-11 for the other two temperatures of potatoes: the fridge potatoes and frozen potatoes and record data.
Safety Precautions:
Five is the highest setting on the hot plate
Always use tongs to put in potato and remove beaker
Wear goggles and apron at all times & long hair must be put up
Keep safe distance from oil
Watch oil at all times
No eating/ drinking
2 drops max of water added to the oil
Tell Ms. Allen if anything breaks or if anyone gets hurt
Fire blanket if someone is on fire
Main office number #: 2-3880
No sitting near hot plate
No more than 50 mL of oil in large beaker
Data Tables:
The volume reached, in decibels, of potatoes of different temperatures after about 15 seconds of being put in hot oil.
Room Temp.
Fridge
Freezer
Trials
Starting Temp.
(°F)
Original Volume
(decibel)
After cooking
(decibel)
Starting Temp.
(°F)
Original Volume
(decibel)
After cooking
(decibel)
Starting Temp.
(°F)
Original Volume (decibel)
After cooking
(decibel)
1
66
50
57
51
50
62
35
52
67
2
66
56
54
51
50
60
35
50
63
3
66
56
56
51
50
57
35
50
63
The Percentage of Change in the Volume Released of Different Temperature Potatoes
Room Temp.
Fridge
Freezer
Trials
Starting Volume
(decibel)
After Cooking (decibel)
Percentage of increase of volume
Starting Volume (decibel)
After Cooking (decibel)
Percentage of increase of Volume
Starting Volume (decibel)
After Cooking
(decibel)
Percentage of increase of Volume
1
50
57
13.1%
50
62
21.4%
52
67
25.2%
2
56
54
-3.6%
50
60
18.2%
50
63
23.0%
3
56
56
0%
50
57
13.1%
50
63
23.0%
Average
54
56
3.37%
50
60
17.57%
52
64
23.73%
Graph:
Conclusion:
As the initial temperature of the potato decreased, the volume, in decibels, increased after being cooked in hot oil. When the potato was room temperature, or 65 degrees fahrenheit, the decibel level ended up increasing by an average of 3.37%. In comparison, the potatoes that were in the fridge produced sound that increased from the original volume by 17.57%. Finally, the potatoes that were in the freezer had an increase in decibel level that was, on average, 23.73% higher. The trend that can be observed is as the internal temperature of the potato decreases, the volume produced tends to increase. These results support the hypothesis, which stated that the colder the potato the more sound would be produced.
Molecularly, the reason for colder substances, especially those encased in ice, making noise when immediately exposed to water is due to several things. The ice shell subliminates. The rapid change in form caused by sublimation as well as the ice formed around the potato allowed the ice to turn into gas and create a fast reaction where the moisture needed to move quickly in order to evaporate and this speed caused the noise to be louder.
Water forms a thin shell made of water vapor which delays the evaporation and allows it to bounce around for longer. A similar thing happens with the gases being released from the melting ice. Water also has a very high heat capacity so it has a stronger reaction when suddenly exposed to heat than other molecules would. The heat spreads out due to entropy which heats up the surface covered in ice, but because of thermal energy and the colder temperature throughout it takes longer for something frozen to become heated all the way through. In summary, the more moisture on the exterior of an object the more noise it will make when immediately exposed to a hot temperature. For that reason, the frozen potato will make more noise when it begins to cook, which supports the hypothesis.
Discussion:
Chefs can use the sound of food to determine whether or not it is cooked because generally the louder the sound the food reaches the more cooked it is. Sound is produced when water or a similar liquid seeps out and begins to evaporate. Generally this is a good test in the doneness of the food because as things cook they become sealed off and lose some moisture. However, in this test, because the moisture was on the outside of the potato and not contained inside, the sound would be loud until the ice melted and subsequently quiet down while it was cooking until more moisture was released from the interior of the potato. Although it may seem like a food product that is louder will be done faster, louder foods generally contain more moisture which, before evaporating, bubbles up and creates gas bubbles, giving the illusion of cooking more quickly.
There were several uncontrollable variables. One was the amount of noise other people in the room made while the volume was being measured. Another was the heat of room temperature as the potatoes sat in the classroom. As the heat in the classroom fluctuated, the heat of the room temperature would also fluctuate, not keeping a steady temperature and possibly changing the temperature contrast between the potato and the hot oil. Finally, the amount of moisture contained in the potatoes was unable to be measured within the test conducted so that may have caused a slight fluctuation in the producible sound.
One change made to the procedure was in the second day of testing. The tests were restarted because the first day the beaker size was too big so the oil was not heating up. Also, the oil wasn’t high enough to fully submerge the potatoes in the oil. These problems propelled the change to a smaller beaker on the second day of testing. This could have been avoided by seeing, before putting the beaker on the heat, if the oil would fully submerge the potato.
One future investigation that could be conducted is seeing how letting the potato cook in the oil longer could affect the amount of sound released. Another future investigation that could be conducted is seeing how the volume the potato reached impacted how cooked it was by measuring the internal temperature of the potato after it was removed from the oil.
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