Why do water droplets sometimes form on the outside of a glass of ice water?

Question

1.) The temperature of the glass is cold enough to cool the air around the glass. The decreasing kinetic energy of the air molecules causes water vapor in the air to undergo a state change and condense into liquid, which forms droplets on the outside of the glass.

2.) The temperature of the glass is cold enough to cool the air around the glass. The increasing kinetic energy of the air molecules adds water vapor to the air and forms droplets on the outside of the glass.

3.) The temperature of the glass is cold enough to cool the air around the glass. The increasing kinetic energy of the air molecules causes water vapor in the air to undergo a state change and condense into a liquid, which forms droplets on the outside of the glass.

4.) The temperature of the glass is cold enough to cool the air around the glass. The increasing kinetic energy of the air molecules causes water vapor in the air to undergo a state change and become a solid, which forms droplets on the outside of the glass.

Answer 1

3.) The temperature of the glass is cold enough to cool the air around the glass. The increasing kinetic energy of the air molecules causes water vapor in the air to undergo a state change and condense into a liquid, which forms droplets on the outside of the glass.

Answer 2

Zoe rides her bike down a steep hill and has to use the brakes a lot to keep from crashing. At the bottom of the hill, she notices that her bike’s brakes have gotten very hot. Why?

1.) The force Zoe applied by using the brakes made the bike gain so much kinetic energy that it underwent a state change, causing the brakes to heat up.

2.) The force Zoe applied by using the brakes converted the bike’s kinetic energy into thermal energy, causing the brakes to heat up.

3.) The acceleration Zoe applied by going down the hill converted the bike’s kinetic energy into thermal energy, causing the brakes to heat up.

4.) The force Zoe applied by going down the hill increased the motion of particles in the bike chain’s oil, which caused it to undergo a state change into a gas form and stop lubricating the brakes, causing the brakes to heat up.

Answer 3

2.) The force Zoe applied by using the brakes converted the bike’s kinetic energy into thermal energy, causing the brakes to heat up.

Answer 4

A thermometer in a glass of water shows that the temperature in the water is rising. What does this tell you about the molecules in the water?

1.) They are moving faster.

2.) They are moving in a new direction.

3.) They are getting heavier.

4.) They have stopped moving.

Answer 5

1.) They are moving faster.

Answer 6

Which of the following statements about energy is true?

1.) Energy can be created.

2.) Energy can be destroyed.

3.) Energy can be converted from one form to another.

4.) Energy comes in two forms: heat and light.

Answer 7

3.) Energy can be converted from one form to another.

Answer 8

What energy transfer occurs when an object that’s sitting on a shelf falls to the floor?

1.) Sound energy is converted to potential energy.

2.) Thermal energy is converted to kinetic energy.

3.) Potential energy is converted to kinetic energy.

4.) Kinetic energy is converted to potential energy.

Answer 9

3.) Potential energy is converted to kinetic energy.

Answer 10

Object A and Object B made direct contact for 15 minutes. The temperature of each object was measured before contact was made and after the objects were separated. Object A’s temperature increased by 2°C , and Object B’s temperature dropped by 5°C . Which statement accurately describes the change that has occurred?

1.) The temperature changes indicate that the motion of molecules in both objects decreased.

2.) The temperature changes indicate that kinetic energy contained in Object B has released to the air.

3.) The temperature changes indicate that kinetic energy has transferred from Object B to Object A.

4.) The temperature changes indicate that the motion of molecules in Object B sped up faster than that of molecules in Object A.

Answer 11

3.) The temperature changes indicate that kinetic energy has transferred from Object B to Object A.