Thermal conductivity of metal and wood | Thermodynamics | Physics | Khan Academy

TL;DR

Metal feels colder than wood even though they are at the same temperature because metal is better at taking heat away from the body.

Transcript

• [Voiceover] So if you're in a room of some kind I encourage you to try a little experiment right now. So look around the room and see if there's something in the room that's made out of wood, or maybe paper, or cloth, and it's been in the room for some time, so hopefully it has the temperature of the room. And then find something else that's made... Read More

Key Insights

• 🥵 Metal feels colder than wood at the same temperature because it is better at taking heat away from the body.
• ❓ The perception of temperature is influenced by the contact area between the body and the material.
• 🥵 The density of the material affects the speed at which heat is transferred, with denser materials transferring heat faster.
• 😘 Wood feels warmer compared to metal due to its lower density and less contact area.

Questions & Answers

Q: Why does metal feel colder than wood even when they are at the same temperature?

The feeling of coldness is due to the metal's ability to transfer heat away from the body more efficiently than wood. Metal surfaces are denser and smoother, facilitating faster heat transfer.

Q: What is the role of contact area in the perception of temperature?

The perception of temperature is affected by the contact area between the body and the material. Metal surfaces provide more contact area, allowing for faster heat transfer, which gives the sensation of coldness.

Q: How does the density of the material affect the perception of temperature?

Metal surfaces are denser than wood surfaces, resulting in more collisions between the molecules of the body and the metal. This increases the speed at which heat is transferred from the body to the metal, making it feel colder.

Q: Why does wood feel warmer compared to metal?

Wood feels warmer compared to metal because it has less contact area and lower density. This leads to slower heat transfer from the body to the wood, resulting in a warmer sensation.

Summary & Key Takeaways

• Metal and wood that have been in a room at the same temperature will feel different when touched, with metal feeling colder.

• The feeling of coldness is due to the metal's ability to transfer heat away from the body faster than wood.

• Metal surfaces are denser and smoother than wood surfaces, allowing for more efficient heat transfer.