Thermal Energy

Lava is hot liquid rock. When lava flows over solid ground, the solid ground beneath it increases in temperature. What happens to the molecules in the solid ground when the temperature is increasing?

• More heat molecules combine with the molecules in the ground.

• The cold energy of the molecules in the ground decreases.

• The energy of the molecules in the ground decreases.

• The energy of the molecules in the ground increases.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

NGSS.MS-PS3-5

James is in the kitchen cooking and is going to stack one pan on top of another pan. The two pans are the same size and have the same number of molecules. The diagram above shows the pans now, before they touch each other. Use the information in the diagram to answer the question. How does the temperature of the top pan compare with the temperature of the bottom pan now, and what will happen after the pans have been touching for a while?

• Before the pans touch, the bottom pan is hotter than the top pan. Once the pans are touching, the bottom pan will transfer kinetic energy to the molecules in the cooler top pan until both pans reach the same temperature, which will be in between their starting temperatures.

• Before the pans touch, the bottom pan is hotter than the top pan. Once the pans are touching, the cooler top pan will gain kinetic energy until the molecules in both pans have an energy of 70, because hotter things increase the temperature of cooler things.

• Before the pans touch, the bottom pan is cooler than the top pan. Once the pans are touching, the top pan will transfer kinetic energy to the molecules in the cooler bottom pan until both pans reach the same temperature, which will be in between their starting temperatures.

• Before the pans touch, the two pans are different temperatures. Once the pans are touching, both kinetic energy and cold energy will transfer between the molecules in the two pans until both pans reach the same temperature, which will be in between their starting temperatures.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

NGSS.MS-PS3-5

An architect is stacking pieces of plastic to make two columns in a model building. The diagram above shows the pieces of plastic before they touch each other. Use the information in the diagram to answer the question. After they have been touching for a while, which of the two top plastic pieces will be cooler, and why?

• The larger top plastic piece will be cooler than the smaller top plastic piece. It started with more total energy, so less energy had to transfer for both pieces in the stack to reach the same total energy.

• The larger top plastic piece will be cooler than the smaller top plastic piece, because the energy that transferred to it was spread out over more molecules.

• Both pieces will be the same temperature, because both of the bottom pieces had the same amount of energy to transfer and the molecules in the top plastic start with the same energy.

• The smaller top plastic piece will be cooler than the larger top plastic piece, because less energy has to transfer for the molecules to reach the same temperature as the molecules of the bottom plastic.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

NGSS.MS-PS3-5

Carl put an apple on top of an ice pack in his lunch bag. By lunchtime the temperature of his apple had decreased. What happened to the molecules in the apple when the temperature of the apple decreased?

• The energy of the molecules in the apple decreased.

• The cold energy of the molecules in the apple increased.

• The apple lost heat molecules.

• The energy of the molecules in the apple increased.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

NGSS.MS-PS3-5

Rogan is playing cards and is about to put one card on top of another. Both cards are the same size and have the same number of molecules. The diagram above shows the cards now, before they touch each other. Use the information in the diagram to answer the question.

How does the temperature of the top card compare with the temperature of the bottom card before the cards touch, and what will happen after the cards have been touching for a while?

• Before the cards touch, the top card is cooler than the bottom card. Once the cards are touching, the bottom card will transfer kinetic energy to the molecules in the cooler top card until both cards reach the same temperature, which will be in between their starting temperatures.

• Before the cards touch, the top card is hotter than the bottom card. Once the cards are touching, the cooler bottom card will gain kinetic energy until both cards’ molecules have an energy of 28, because hotter things increase the temperature of cooler things.

• Before the cards touch, the top card is hotter than the bottom card. Once the cards are touching, the top card will transfer kinetic energy to the molecules in the cooler bottom card until both cards reach the same temperature, which will be in between their starting temperatures.

• Before the cards touch, the two cards are different temperatures. Once the cards are touching, both kinetic energy and cold energy will transfer between the molecules in the two cards until both cards reach the same temperature, which will be in between their starting temperatures.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

NGSS.MS-PS3-5

Kekoa made a pot of applesauce, then put it into containers to store it. The containers are placed in two separate stacks. The diagram above shows the containers of applesauce before they touch each other. Use the information in the diagram to answer the question.

After a while, which of the two top containers will be cooler, and why?

• The smaller top container will be cooler than the larger top container, because less energy has to transfer for the molecules to reach the same temperature as the molecules of the bottom container.

• Both top containers will be the same temperature, because both of the bottom containers have the same amount of energy to transfer and the molecules in the top containers started with the same energy.

• The larger top container will be cooler than the smaller top container. It started with more total energy, so less energy has to transfer for both containers in the stack to reach the same total energy.

• The larger top container will be cooler than the smaller top container, because the energy that transferred to it is spread out over more molecules.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

NGSS.MS-PS3-5