Conduction!
What is conduction?
The first way that heat transfers from one object to another is conduction. Conduction involves object that are in direct contact. If the objects are not in direct contact, then the heat can not be conducted from one to the other Have you ever accidentally touched a hot pot or a light bulb that had been on for a long time? If you have, you have experienced conduction. The heat energy from the hot object transfered to your hand through conduction. Source: http://ed.sc.gov/agency/ccr/Standards-Learning/documents/2014Grade6_SupportDoc.pdf
|
Source: http://www.enerchek-insulation.com/about-insulation/
Since your hand is in direct contact with pans when you cook, it is important to protect your hand from the heat.
|
Source: http://electron6.phys.utk.edu/101/CH7/Heat%20Flow.htm
|
How does conduction work?
During conduction, the transfer of energy as heat occurs between particles as they collide within a substance or between two objects in contact. The energy always transfers from an area of higher temperature to an area of lower temperature. Which way do you think heat would transfer if the two objects to the left came into direct contact? Source: http://ed.sc.gov/agency/ccr/Standards-Learning/documents/2014Grade6_SupportDoc.pdf
|
Do all objects conduct heat evenly?
All materials do not conduct heat energy equally well. Poor conductors of heat are called insulators. Good conductors of heat are called conductors. For example, if a plastic spoon and a metal spoon are placed into a hot liquid, the handle of the metal spoon will get hot quicker than the handle of the plastic spoon because the heat is conducted through the metal spoon better than through the plastic spoon.
All materials do not conduct heat energy equally well. Poor conductors of heat are called insulators. Good conductors of heat are called conductors. For example, if a plastic spoon and a metal spoon are placed into a hot liquid, the handle of the metal spoon will get hot quicker than the handle of the plastic spoon because the heat is conducted through the metal spoon better than through the plastic spoon.
Source: http://ed.sc.gov/agency/ccr/Standards-Learning/documents/2014Grade6_SupportDoc.pdf
Source: http://www.kalyx.com/shopexd.asp?id=1039660
Materials like wood and plastic are examples of insulators. When stirring your coffee in the morning, it is safer to use a plastic spoon because it does not transfer heat well.
|
Source: http://www.greatsupplies.co.uk/Metal-Tea-Spoon-Economy-pack-of-12
Metal is an example of a conductor. If you're stirring your coffee with a metal spoon, be careful because the spoon could conduct the heat to your hand.
|
Why do I care? Whether you're cooking dinner or stirring your morning cup of coffee, it is important to know how heat energy will transfer from one object to another to help you keep from getting burnt. Since some materials do not conduct heat as well as others, these materials are usually better to use when dealing with something hot.
Let's see it in action!
Below is a video about heat transfer through conduction. As you watch the video, pay attention to how the molecules move when heat is transferred and which way the heat travels.
Below is a video about heat transfer through conduction. As you watch the video, pay attention to how the molecules move when heat is transferred and which way the heat travels.
Source: https://www.youtube.com/watch?v=bMsKIfxliA4
After you've seen it in action, draw how the molecules move during conduction on your notecatcher. Draw how molecules move in both insulators and conductors.
Now that you know all about conduction, you're ready to move onto... convection!