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The Efficiency of an Electric Kettle
The Efficiency of an Electric Kettle
In this experiment a temperature sensor is used to measure the rate of temperature rise of a known mass of water heated in an electric kettle.
Theory
Theory
The temperature change of the water, ΔT is related to the heat added, Q by the equation
Q=mCΔT
The power of the kettle, P is the heat delivered per unit time Q/Δt so if we divide the first equation by Δt we get
Q/Δt = mCΔT/Δt
So
P = mCΔT/Δt
Method:
Method:
Record the power of the kettle from the information on the bottom of the kettle.
Measure the mass of the kettle with a balance.
Add 400ml water to the kettle using a beaker.
Measure the mass of the water and kettle with a balance.
Using the LabQuest, set up the temperature probe to record data at 1 sample / second for 300 sec.
Place the temperature probe in the water in the kettle. Let the temperature probe come to equilibrium with the water.
Measure the temperature of the water for 5 min using the temperature probe.
Empty the water from the beaker into the sink.
Repeat for a second kettle.
Compare the efficiency of the two different kettles.
What are some additional questions that could be explored?
Power of Kettle Data
Power of Kettle Data
Kettle Red - 1850-2200 W
Kettle Blue - 1000 W-1200 W
Cost of a cup of tea:
Cost of a cup of tea:
Based on your data, determine the amount of energy required to heat 250mL of water from 24˚ C to 100˚C?
Propane has an energy density of at 50.3 (±0.01) MJ/kg and has an average efficiency of 0.40.
Determine the amount of propane necessary to heat the water for your tea.
Suggest why propane has an average efficiency of 0.40.
At ADNOC, you can purchase 20-kg of propane in a tank for 32.50 AED. Calculate the cost of heating your cup of tea in AED.
Applying the calorimetric techniques of specific heat capacity or specific latent heat experimentally
Molecular theory of solids, liquids and gases
Temperature and absolute temperature
Internal energy
Specific heat capacity
Phase change
Specific latent heat
Two kettles were used in ACS HS260. A graph of the data is shown to the above. The data can be downloaded HERE (download the file then open in LoggerPro).
Using the data to the above answer the questions in the previous section.
Estimate the uncertainty in m, ΔT/Δt and P then calculate the uncertainty in your value of C.
Compare at the two different kettles.
What are some additional questions that could be explored?
Kettle Red was allowed to boil the water for 114s, determine the mass of the water boiled away during this time. m_final (kettle + Water) = 1501.5g ∆m_water = 93.5g
Determine the Specific Heat of Various Metals
Determine the Specific Heat of Various Metals
Applying the calorimetric techniques of specific heat capacity or specific latent heat experimentally
Molecular theory of solids, liquids and gases
Temperature and absolute temperature
Internal energy
Specific heat capacity
Bridging the gap from EM to heat. All resistors produce heat. Some devices are designed specifically to convert electrical power (P=IV) into heat (Q). During this activity will measure the power delivered to an immersion heater. You will be measuring the current (I) and voltage (V) delivered to the immersion heater. You can then measure the change in temperature of the metal cylinder
Discuss the role of the water used to surround the metal cylinder.
While collecting data, Melissa is finding that her range of final temperatures is to narrow to determine a
Online Specific Heat Simulation
Online Specific Heat Simulation
Using the instructions on the site, Determination of Specific Heat.
Follow the instructions for RUN DEMONSTRATION. Indicate how the various materials affect the temperature of the the water in the demonstration.
For the experiment:
Choose a metal and a liquid.
Test 5 different masses of the metal to determine the specific heat capacity of the metal.
Create a graph of '=m∆T (metal) v. '=mC∆T (liquid)
Describe the significance of the slope of the graph.
Describe some pros and cons of using an online simulation vs. an in-lab practical.
New Tab HERE: Determination of Specific Heat
Determine the temperature of a Bunsen Burner - Sample Problem
Determine the temperature of a Bunsen Burner - Sample Problem
As part of an upcoming IA, a student was attempting to determine the temperature of a classroom bunsen burner. She initially placed a solid copper ball of 80 grams (specific heat capacity = 385 J/˚C/kg). She held the ball in place for approximately 4 minutes. She then quickly transferred the metal into an insulated beaker containing 750 ml of 25.0˚C water. She then gently mixed the water while recording the change in temperature. After several minutes the final temperature of the water and copper ball was recorded as 38.9˚C.
Determine the experimental temperature of the bunsen burner used in the setup.
Identify some sources of error the may affect the final results of her IA.
Suggest a possible solution to reducing each of the errors identified.
Mechanical Energy to Heat
Using the experimental setup to the left.
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