Question

activity b: temperature and molecular motion
get the gizmo ready

• click reset, and select the micro view.
• set ice volume to 0 cm³.
• set add/remove heat energy to 0 j/s

question: why do phase changes occur?

1. compare: set the water temperature to 10 °c and click play. observe the water molecules. click reset, set the water temperature to 100 °c, and click play again.

what do you notice? at 10°c, water molecules move relatively slowly and are close together. at 100°c, water molecules move much faster and more spread out.

1. observe: click reset. the average molecular speed of the water molecules is displayed below the container. set the water temperature to 0 °c and add/remove heat energy to 500 j/s. click play.

a. how does the average speed of the water molecules change as they are heated?
the average speed of the water molecules increases as they are heated.
b. does the average molecular speed change as much as the temperature as the water heats up? explain. the average molecular speed does not change as much as the water heats up. this is because temperature is a measure of the average kinetic energy of the molecules, and as the temperature increases, the mass of the molecules remains constant.

1. explain: how is temperature related to the motions of molecules? temperature is a measure of the average kinetic energy of the molecules. as the temperature increases, the average kinetic energy of the molecules.
2. observe: click reset. set the water temperature to -10 °c and add/remove heat energy to 100 j/s. click play. as the ice melts, how do the molecules in the liquid interact with the molecules in the solid?

as the ice melts, the faster moving liquid water molecules interact with the slower moving solid ice molecules.
(activity b continued on next page)

Explanation:

Answer:

Discipline: Natural Science
Sub - field: Physics
Question 1: At 10°C, water molecules move relatively slowly and are close together. At 100°C, water molecules move much faster and more spread out.
Question 2 A: The average speed of the water molecules increases as they are heated.
Question 2 B: The average molecular speed does not change as much as the water heats up. This is because temperature is a measure of the average kinetic energy of the molecules, and as the temperature increases, the mass of the molecules remains constant.
Question 3: Temperature is a measure of the average kinetic energy of the molecules. As the temperature increases, the average kinetic energy of the molecules.
Question 4: As the ice melts, the faster moving liquid water molecules interact with the slower moving solid ice molecules.