Shopping Part 3

Question 1

When a fork is placed in a hot piece of lasagna, thermal energy is transferred up the fork by

Revolt · Accepted Answer

fast-moving particles colliding with slow-moving particles.

Question 2

While Felicia is stirring her hot coffee with a metal spoon, she gets called away. She sets the coffee on the desk and then forgets to come back for it before going home for the weekend. How long will conduction between the spoon and the hot coffee occur?

Revolt · Accepted Answer

Conduction will occur until the spoon and coffee are the same temperature.

Question 3

Kai takes a hamburger off of the grill and puts a piece of cheese on it. Explain how and why the cheese melts when Kai puts it on the hamburger.

Revolt · Accepted Answer

The cheese melts because of conduction, which occurs when two objects of different temperatures are in direct contact. Since the hamburger is warmer than the cheese, thermal energy is transferred from the hamburger to the piece of cheese, causing the temperature of the cheese to rise and eventually melt.

Question 4

In which scenarios does conduction occur? Check all that apply.Ice cream is placed in a bowl chilled to the same temperature.An ice pack is placed on a sprained ankle.A piece of frozen fish is placed in a hot frying pan.A metal pot is held 15 cm above a hot stove.A lizard is lying on a warm rock.

Revolt · Accepted Answer

An ice pack is placed on a sprained ankle.; A piece of frozen fish is placed in a hot frying pan.; A lizard is lying on a warm rock.

Question 5

How do the metal aluminum coils in an air conditioner help keep a house cool?

Revolt · Accepted Answer

They conduct thermal energy from inside the house and release it outside the house.

Question 6

How is thermal energy transferred during convection?

Revolt · Accepted Answer

by movement in fluids

Question 7

The kinetic energy of the molecules [___].

Revolt · Accepted Answer

increases; The kinetic energy of the molecules .: increases; The speed of the molecules .: increases; The density of the fluid .: decreases; The fluid .: rises

Question 8

Which statements best describe convection? Check all that apply.

Revolt · Accepted Answer

Convection occurs in liquids and gases.; Convection transfers thermal energy.; Convection occurs until all of the fluid is at the same temperature.

Question 9

Which describes the motion in a convection current?

Revolt · Accepted Answer

circular motion

Question 10

The diagram shows molecules in a fluid. Explain the sequence of events that happens when this fluid cools down. Be sure to focus on what happens to the molecules and to the fluid in general. Five events should be included in your answer.

Revolt · Accepted Answer

As the fluid cools down, the following sequence of events occurs: 1. The thermal energy of the fluid decreases. 2. The molecules lose kinetic energy and begin to move more slowly. 3. As the molecules slow down, the attractive forces between them pull them closer together. 4. Because the molecules are closer together, the fluid's volume decreases and its density increases (thermal contraction). 5. Eventually, the movement slows enough that the fluid may undergo a phase change, such as freezing into a solid.

Shopping Part 3 Answers

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