Question
Science Fair Report: Which Metal Is Best for Stovetop Cookware?
Purpose of Study
To determine the relative heat conductivity of various metals commonly used in stovetop cookware.
Background
Selecting a pan to use in the kitchen can be complicated. One of the most important factors to consider is what the pan is made of. The purpose of a pan is to transfer energy from the heat source to the food to be cooked. Most stoves either burn gas or use electricity to heat up special heating elements. In a gas stove, the gas comes out of a small round burner at regular intervals. When lit, the burning gas forms a ring of flames about the size of the burner. The heating elements of an electric stove cover more area. However, they also have patterns where there is no heat being produced. Neither kind of stove produces an even heat. It is useful, then, to use pans that can evenly transfer heat energy from the heat source to the food being cooked.
The heat conductivity of a material is how quickly it transfers heat energy. When the flame or heating element comes into contact with a pan, heat energy is conducted directly to the pan. It then spreads from the bottom to the sides. Heat is directly transferred to the food as the pan heats up. In most stovetop cooking situations, you want the pan to heat up quickly and evenly. Pans made of materials with high heat conductivity do this because they transmit heat quickly, which results in even heating.
Hypothesis
If different metals are heated with the same heat source, then they each transfer heat energy at a different rate.
Materials and equipment
4-cup glass measuring cup
Insulating material
Water
Microwave
Thermal conductivity bars (with liquid crystal displays)*
Timer
*Thermal Conductivity Bars with Liquid Crystal Display
The liquid crystal display in the thermal conductivity apparatus used shows temperatures in the range 35°C to 45°C. The different colors of the display indicate the temperatures. The lowest temperature indication is a coppery red color at 33*C, and the hottest is a blue color at over 45°C.
Procedure
1. Wrap the measuring cup with insulating material such as a towel. This limits cooling of the water during the experiment.
2. In the microwave, heat about 3 cups of water in the measuring cup until boiling.
3. Remove the measuring cup carefully from the microwave and place on a flat, heat-proof surface.
4. Immerse about 1 cm of the end of the thermal conductivity bars into the hot water. Be careful to keep the plastic case and liquid crystal display from touching the water.
5. Holding the bars at a constant depth in the water, record the time it takes for the blue color on the liquid crystal display (45°C) to reach the top of each bar.
6. Allow the bars to cool to room temperature. Then repeat steps 2 through 5 twice, for a total of three trials.
Thermometer with liquid crystal display that shows different colors for different temperatures.
Data and Discussion
Four different metal bars were immersed in very hot water (just under 100°C) at the same time. The time it took each metal bar to reach 45°C at the top of the bar was recorded. The results are shown in the table and graph below.
The results were consistent over the three trials. The metals all conducted heat at different rates.
Of the four metals tested, copper conducted heat the fastest, so it had the highest heat conductivity. Aluminum also conducted heat quickly. Brass had a lower heat conductivity, and stainless steel had the lowest heat conductivity. It took the steel much longer to heat up than the other metals.
Charts that plot the data described in the experiment, showing the rate of temperature change of different cooking pans.
Conclusion
Copper had the highest heat conductivity of the four metals. Pans made from copper provide the fastest and most even cooking. Aluminum is another good choice. The entire pan does not need to be made of these metals for even cooking. If the bottom of the pan is copper or aluminum, then the heat from the gas or electric burner can be transferred evenly to the pan.
Multiple Choice Question
Which other property of a material is most likely to affect the rate at which a pan of that material will heat up?
A.
the amount of energy required to raise the temperature of 1 gram of the pan by 1 °C
B.
the amount of heat lost to the environment between the burner and the pan
C.
the amount the pan expands when heated to high temperatures
D.
the tendency for the pan to chemically react with various types of food being heated in the pan
Purpose of Study
To determine the relative heat conductivity of various metals commonly used in stovetop cookware.
Background
Selecting a pan to use in the kitchen can be complicated. One of the most important factors to consider is what the pan is made of. The purpose of a pan is to transfer energy from the heat source to the food to be cooked. Most stoves either burn gas or use electricity to heat up special heating elements. In a gas stove, the gas comes out of a small round burner at regular intervals. When lit, the burning gas forms a ring of flames about the size of the burner. The heating elements of an electric stove cover more area. However, they also have patterns where there is no heat being produced. Neither kind of stove produces an even heat. It is useful, then, to use pans that can evenly transfer heat energy from the heat source to the food being cooked.
The heat conductivity of a material is how quickly it transfers heat energy. When the flame or heating element comes into contact with a pan, heat energy is conducted directly to the pan. It then spreads from the bottom to the sides. Heat is directly transferred to the food as the pan heats up. In most stovetop cooking situations, you want the pan to heat up quickly and evenly. Pans made of materials with high heat conductivity do this because they transmit heat quickly, which results in even heating.
Hypothesis
If different metals are heated with the same heat source, then they each transfer heat energy at a different rate.
Materials and equipment
4-cup glass measuring cup
Insulating material
Water
Microwave
Thermal conductivity bars (with liquid crystal displays)*
Timer
*Thermal Conductivity Bars with Liquid Crystal Display
The liquid crystal display in the thermal conductivity apparatus used shows temperatures in the range 35°C to 45°C. The different colors of the display indicate the temperatures. The lowest temperature indication is a coppery red color at 33*C, and the hottest is a blue color at over 45°C.
Procedure
1. Wrap the measuring cup with insulating material such as a towel. This limits cooling of the water during the experiment.
2. In the microwave, heat about 3 cups of water in the measuring cup until boiling.
3. Remove the measuring cup carefully from the microwave and place on a flat, heat-proof surface.
4. Immerse about 1 cm of the end of the thermal conductivity bars into the hot water. Be careful to keep the plastic case and liquid crystal display from touching the water.
5. Holding the bars at a constant depth in the water, record the time it takes for the blue color on the liquid crystal display (45°C) to reach the top of each bar.
6. Allow the bars to cool to room temperature. Then repeat steps 2 through 5 twice, for a total of three trials.
Thermometer with liquid crystal display that shows different colors for different temperatures.
Data and Discussion
Four different metal bars were immersed in very hot water (just under 100°C) at the same time. The time it took each metal bar to reach 45°C at the top of the bar was recorded. The results are shown in the table and graph below.
The results were consistent over the three trials. The metals all conducted heat at different rates.
Of the four metals tested, copper conducted heat the fastest, so it had the highest heat conductivity. Aluminum also conducted heat quickly. Brass had a lower heat conductivity, and stainless steel had the lowest heat conductivity. It took the steel much longer to heat up than the other metals.
Charts that plot the data described in the experiment, showing the rate of temperature change of different cooking pans.
Conclusion
Copper had the highest heat conductivity of the four metals. Pans made from copper provide the fastest and most even cooking. Aluminum is another good choice. The entire pan does not need to be made of these metals for even cooking. If the bottom of the pan is copper or aluminum, then the heat from the gas or electric burner can be transferred evenly to the pan.
Multiple Choice Question
Which other property of a material is most likely to affect the rate at which a pan of that material will heat up?
A.
the amount of energy required to raise the temperature of 1 gram of the pan by 1 °C
B.
the amount of heat lost to the environment between the burner and the pan
C.
the amount the pan expands when heated to high temperatures
D.
the tendency for the pan to chemically react with various types of food being heated in the pan
Answers
GPT-4o mini
The most appropriate answer to the multiple-choice question is:
**A. the amount of energy required to raise the temperature of 1 gram of the pan by 1 °C**
This property, known as specific heat capacity, directly affects how quickly a pan will heat up to the temperature required for cooking. Materials with a lower specific heat capacity will heat up more quickly compared to those with a higher specific heat capacity, assuming all other factors are equal.
While options B, C, and D may influence aspects of cooking or the performance of a pan, they do not directly relate to the rate of heating of the material itself as specific heat capacity does.
**A. the amount of energy required to raise the temperature of 1 gram of the pan by 1 °C**
This property, known as specific heat capacity, directly affects how quickly a pan will heat up to the temperature required for cooking. Materials with a lower specific heat capacity will heat up more quickly compared to those with a higher specific heat capacity, assuming all other factors are equal.
While options B, C, and D may influence aspects of cooking or the performance of a pan, they do not directly relate to the rate of heating of the material itself as specific heat capacity does.