Does the volume of water affect efficiency of heater?

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Discussion Overview

The discussion revolves around the question of whether the volume of water in a calorimeter affects the efficiency of an immersion heater. Participants explore the relationship between water volume and heating efficiency, with a focus on experimental results and scientific reasoning.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Homework-related

Main Points Raised

  • One participant reports that their results indicate an increase in water volume leads to a decrease in efficiency, seeking explanations for this observation.
  • Another participant suggests that increased surface area with more water could lead to greater heat loss, potentially accounting for the observed decrease in efficiency.
  • Concerns are raised about the clarity of the experimental setup and the definitions of variables used in calculations, particularly regarding the use of temperature (T) and time.
  • Some participants assert that immersion heaters are generally considered to be nearly 100% efficient in converting electrical energy to heat, with minimal losses.
  • Calibration of the calorimeter is mentioned as a necessary step to accurately measure the efficiency of the heating process.
  • A question is posed regarding whether the water reached boiling point during the experiment, which could influence the results.

Areas of Agreement / Disagreement

Participants express differing views on the efficiency of immersion heaters and the factors affecting it, indicating that multiple competing perspectives remain without a consensus on the reasons behind the experimental results.

Contextual Notes

Limitations include a lack of detailed information about the experimental setup, measurements taken, and the specific analysis performed, which may affect the interpretation of results.

Who May Find This Useful

This discussion may be useful for students conducting experiments related to thermal efficiency, educators seeking examples of experimental analysis, and individuals interested in the principles of heat transfer in calorimetry.

Daniel Manetas
Ok, so i did a physics experiment a few days ago and now i have to do a write up. The question is does the volume of water in the calorimeter affect the efficiency of the immersion heater? Could someone pls explain to me what happens & y? My results showed that as you increase the volume, the efficiency decreases. Anyone know why that happened?
 
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Welcome to PF Daniel!

You will have to provide some details of your experiment. The first step in getting help is providing a clear statement of the problem.

AM
 
It's not only the first step in getting help, it's also the indispensable first step to find an answer!
 
Ok, so i used the formula q=mcT to work out the energy output and P=VI then E=PxT to work out the energy input, then divide these by each other to work out the efficiency. Does anyone know why i got the results i did? Like the scientific reasoning behind it.
 
Have you considered what changes when you increase the volume of water? There is more surface area, so there could be more heat loss. Could that account for it.?
 
You will have to explain:
1. How you conducted the experiment I.e. the setup, what you did and what you measured
2. Your result, and
3. How you analysed the results

Just a few quick comments:

You seem to be using T for two different quantities: 1. change in temperature and 2. Time.

It is difficult to understand how an electric heating element would be much less than 100% efficient in converting electrical energy into heat.

AM
 
Last edited:
+1

Immersion heaters are generally 100% efficient in that all the heat they dissipate ends up in the water. Some might be lost by thermal conduction down the wires but that's usually small enough to be negligible.

I agree with ntl2009 in that the losses might affect the results. Normally you have to calibrate the calorimeter, perhaps by measuring how much power is needed to maintain a steady water temperature.
 
Did the water boil?
 

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