How Heat Energy Transfers Through a Pan of Water

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Discussion Overview

The discussion revolves around the mechanisms of heat energy transfer from a gas flame to a pan of water. Participants explore the concepts of conduction, convection, and radiation, examining how these processes contribute to heating the water in the pan.

Discussion Character

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

Main Points Raised

  • One participant questions how energy transfers from the flame to the water, identifying conduction as a starting point but expressing uncertainty about subsequent processes.
  • Another participant asks for the three methods of heat transport, suggesting that convection and radiation are the other two methods, with a query about their roles in boiling water.
  • A participant confirms that convection and radiation are indeed the other two methods and provides hints about the heating process, including the role of the burning gas and the conduction of heat through the pan.
  • There is a discussion about the sequence of heat transfer, with one participant noting that the bottom layer of water heats first and leads to convection.
  • Another participant mistakenly identifies the first and third methods as radiation, prompting a correction that both are convection.
  • A participant describes the behavior of a candle flame in microgravity, contrasting it with the convection observed on Earth, and explains how convection occurs in the pan as the heated water rises and is replaced by cooler water.
  • One participant mentions the mixture of conduction and radiation when using an electric ring, expressing uncertainty about the proportions of heat transfer by each method.
  • A later reply acknowledges a lack of prior study on the topic, indicating a learning process in understanding heat transfer mechanisms.

Areas of Agreement / Disagreement

Participants generally agree on the three methods of heat transfer (conduction, convection, and radiation), but there are disagreements regarding the specific roles and sequences of these processes in the context of heating water in a pan.

Contextual Notes

Some participants express uncertainty about the proportions of heat transfer methods and the specific mechanisms involved, indicating a need for further clarification on these points.

Who May Find This Useful

This discussion may be useful for students studying thermodynamics, individuals interested in heat transfer processes, or anyone seeking to understand the principles of energy transfer in cooking applications.

Molly1235
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"Explain how energy gets from the flame of a gas cooker to the contents of a pan of water above the flame".

This has stumped me...I've only got as far as the metal pam conducting heat energy, but them I don't know why it is transferred through the water...?
 
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What are the three ways heat can be transported? Conduction is one, what are the other two and which do you think is likely to occur and where?
 
CWatters said:
What are the three ways heat can be transported? Conduction is one, what are the other two and which do you think is likely to occur and where?

Convection and radiation? Radiation would occur to boil the water wouldn't it? I'm not sure about convection though...
 
Convection and radiation are the other two.

OK here are some hints...

1) The burning gas rises up to the pan and flows up the sides of the pan due to...??

2) The heat is conducted through the walls of the pan into the water. (You already got that).

3) The layer of water on the bottom of the pan is heated first. Soon it is hotter than rest of the water so...??
 
Is the first convection and third radiation?
 
...as radiation gives the particles of the food more energy, so they vibrate faster and produce heat which heats the food?
 
Sorry but 1 and 3 are both convection.

Inside the space station where there is no gravity a candle flame is spherical because there is no convection. On Earth the hot flame cause the burnt gas and air to rise by convection.

Inside the pan the water on the bottom is heated first by conduction so it becomes less dense than the rest of the water and convection is triggered. The hot water rises and is replaced by colder water which sinks and is heated in turn by conduction. You can see the water moving in this vid with the aid of some die..



With an electric ring you would get a mixture of conduction and radiation between the red hot ring and the bottom of the pan although I'm not sure what proportion of the heat flows by each method.
 
Last edited by a moderator:
Oooh ok! I'm with you! Apologies, I haven't actually studied this so I'm working from scratch! Always helpful when you get set work you've been taught nothing about...
 

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