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Chapter 2, Lesson 1 Multimedia

Room Temperature Washers in Hot Water

Several metal washers at room temperature are placed in cup of hot water. The temperature of the water decreases, and the temperature of the washers increases.

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  • 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.

Hot Washers in Room Temperature Water

Several metal washers at high temperature are placed in cup of cold water. The temperature of the water increases, and the temperature of the washers decreases.

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  • 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.

Heated Spoon

A room temperature metal spoon is placed in hot water. A close up of the molecules in the spoon and the molecules that comprise the water shows that the molecules in the water transfer their energy in the form of heat to the spoon.

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  • 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.

Cooled Spoon

A hot metal spoon is placed in cold water. A close up of the molecules in the spoon and the molecules that comprise the water shows that the molecules in the spoon transfer their energy in the form of heat to the water. The spoon thus cools down and the water heats up.

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  • 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.

Spoon in Hot Water Before & After

An illustration showing a spoon with circles and two motion lines, indicating that the spoon is at room temperature.An illustration showing a spoon with in a cup of water with no motion lines.

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

Hot Spoon in Room Temperature Water

An illustration showing a spoon with circles and three motion lines, indicating that the spoon is hot.An illustration showing a spoon with in a cup of water with no motion lines.

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

Conducting Energy

A person's hand comes into contact with a small piece of metal and a small piece of cardboard. When the hand touches the metal, the person's hand feels cold. Because metal is a good conudctor of energy, it draws heat energy away from the person's hand mroe easily than does the cardboard. So, when the person touches the cardboard, not much energy is transferred, and the person's hand doesn't feel cold.

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  • 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.