Chapter 2, Lesson 1 Multimedia

Room Temperature Washers in Hot Water

When room-temperature washers are placed in hot water, the temperature of the washers increases and the temperature of the water decreases.
Energy from the water is transferred to the washers.

When hot washers are placed in room-temperature water, the temperature of the washers decreases and the temperature of the water increases.
Energy from the washers is transferred to the water.

Molecules in the hot water are moving faster than the atoms in the spoon. Faster-moving water molecules strike the atoms of the spoon,transferring some of their energy to them.
The atoms in the spoon move faster (increasing temperature) and the molecules in the water move slower (decreasing temperature).
When fast-moving atoms or molecules hit slower-moving atoms or molecules and increase their speed, heat is transferred. This process is called conduction.

The atoms in the hot spoon are moving faster than the water molecules.
Faster-moving atoms in the spoon strike the water molecules, transferring some of their energy to them.
The atoms in the spoon move slower (decreasing temperature) and the water molecules move faster (increasing temperature).
When fast-moving atoms or molecules hit slower-moving atoms or molecules and increase their speed, heat is transferred. This process is called conduction.

Draw motion lines in the 'After' picture to show that heat was transferred when the spoon was placed in the water.

Draw motion lines in the 'After' picture to show that heat was transferred when the spoon was placed in the water.

The molecules in your finger are moving faster than the molecules in the room-temperature metal. But because metal is a good conductor, the heat from your finger is transferred to the metal. This decreases the motion of the molecules in your skin and makes your skin feel colder.
The molecules in your finger are moving faster than the molecules in the room-temperature cardboard. But because cardboard is a poor conductor, the heat energy from your finger is barely transferred to the cardboard. Since the motion of molecules in your skin stays about the same, your skin feels normal.