Why the spoon gets hot
Metals pass heat along. Wood hardly does.
The kitchen puzzle
In the kitchen, vessels for heating are made of metal, but their handles are made of wood or other materials. Is there a reason?
A metal spoon and a wooden spoon stand in the same hot water for the same time. Which one will feel hotter at the top?
What this lesson covers
The idea
The transfer of heat from one point of a material to another is called conduction and materials that transfer heat are conductors; metals are good conductors of heat, wood is a poor one.
The kitchen puzzle
In the kitchen, vessels for heating are made of metal, but their handles are made of wood or other materials. Is there a reason?
A metal spoon and a wooden spoon stand in the same hot water for the same time. Which one will feel hotter at the top?
- The metal spoon
- The wooden spoon
- Both feel the same
Two spoons in hot water
Slide the time forward to about four minutes. Then touch the top of each spoon.
Conduction
The transfer of heat from one point of a material to another is called conduction, and materials that transfer heat are called conductors. Metals are good conductors of heat. Wood is a poor conductor of heat.
That is why cooking vessels are mostly metal, and their handles are made of wood or other materials that do not conduct heat. You will learn more in the chapter "Heat Transfer in Nature".
- Spoon | Top of the handle | Heat
- Metal | hot to touch | travels up the handle
- Wood | stays cool | hardly travels
Notes
Conduction is the transfer of heat from one point of a material to another. Metals are good conductors of heat. Wood is a poor conductor.
Check yourself
The transfer of heat from one point of a material to another is called...
The metal spoon was hotter to touch than the wooden spoon. What does this show?
Why do cooking vessels have handles of wood or other materials that do not conduct heat?
Which of these is a good conductor of heat?
- conduction — correct. Yes! Heat is conducted along the material.
- malleability. Malleability is being beaten into thin sheets.
- sonority. Sonority is the ringing sound of metals.
- Metal is a poor conductor of heat. It is the other way round: metal passes heat on easily.
- Wood is a good conductor of heat. Wood passes heat on poorly.
- Metal is a good conductor of heat — correct. Yes! Heat travelled up the metal spoon.
- So that the handle stays cool enough to hold — correct. Yes! Such handles are poor conductors of heat.
- So that the vessel looks nicer. Looks are not the reason.
- So that the food cooks faster. The metal part cooks the food. The handle just keeps your hand safe.
- A wooden spoon. Wood is a poor conductor of heat.
- A metal spoon — correct. Yes! Metals conduct heat well.
- Neither. Metals conduct heat well.