1. Day 26 What do liquid water and water vapor have in common?
They’re both made up of water particles that move randomly from place to place.
How are liquid water and water vapor different?
Water vapor particles move faster, bounce harder, and spread out more than liquid water particles.
Additional differences students may come up with:
You can see liquid water, but water vapor is invisible.
Water vapor doesn’t stay in a container like liquid water.
Water vapor is compressible, and liquid water isn’t.
Daily Warm-Up Exercises
Compare Evaporation & Condensation 1

2. Compare Evaporation and Condensation
Contrasting Case Activity 6
Weather & Water, Investigation 6: Water in the Air
Compare Evaporation & Condensation

3. How did Damien get dry without a towel?
A Forgotten Towel
Damien was swimming on a hot
summer day. When he got
out of the pool, he saw
he had forgotten his towel.
Even though it was a hot day,
he started to feel cold. He sat in the sun and, a half hour later, he was dry and he felt warm again.
How did Damien get dry without a towel?
Read the description and the question at the bottom of the slide. Give students a moment to think about it, then tell them they will look at another case before sharing ideas or writing their answers.
Compare Evaporation & Condensation

4. Spilled Water
Tameka was carrying a glass of water from the kitchen to her bedroom. As she was walking, she spilled some water on the floor. She forgot about it while she did her homework. When she went back an hour later, the floor was dry. How did the floor get dry?
Read the description and the question. Give students a moment to think about it, then distribute the cards (worksheet 21) and have them try to figure out which card best describes what happened in each situation. Encourage them to offer evidence from the cards to support their choices. They should decide that both cases are examples of evaporation.
Compare Evaporation & Condensation

5. Evaporation Water changes from liquid to gas (water vapor)
Heat transfers from the environment to water molecules
Water molecules gain energy when they evaporate
Things “air dry” when liquid water changes to water vapor
Introduce evaporation and walk through its characteristics.
Compare Evaporation & Condensation

6. Answer Questions When Damien got out of the pool, he saw
he had forgotten his towel. Even
though it was a hot day, he started
to feel cold. He sat in the sun and, a half
hour later, he was dry and he felt warm again.
As Tameka was carrying a glass of water to her bedroom, she spilled some on the floor. When she went back an hour later, the floor was dry.
Distribute worksheet 22 and have students use the information on the evaporation card to answer the first set of questions.
Sample responses:
1. Damien got dry because the water on his skin evaporated. Heat transferred from his skin to the liquid water molecules, and that's what made him feel cold. When the liquid molecules gained energy, they changed to water vapor and joined the surrounding air.
2. The floor got dry because the water on the floor evaporated. Heat transferred from the floor and surrounding air to the liquid water molecules. When the liquid molecules gained energy, they changed to water vapor and joined the surrounding air.
3. Both situations are examples of evaporation. Both involve liquid water molecules gaining energy from the environment and changing to water vapor.
Compare Evaporation & Condensation

7. Question 1 How did Damien get dry? The water on his skin evaporated.
He felt cold because heat transferred from his skin to the liquid water molecules.
When the liquid molecules gained energy, they changed to water vapor and joined the surrounding air.
Compare Radiation & Conduction
Compare Evaporation & Condensation 7

8. Question 2 How did the floor get dry?
The water on the floor evaporated.
Heat transferred from the floor and surrounding air to the liquid water molecules.
For question 3, students should say that both are examples of evaporation. Both involve liquid water molecules gaining energy from the environment and changing to water vapor.
When the liquid molecules gained energy, they changed to water vapor and joined the surrounding air.
Compare Radiation & Conduction
Compare Evaporation & Condensation 8

9. The Water Stain
Raymond’s grandmother always scolded him for not using coasters to protect the table from water stains. One humid day, he poured a cold glass of soda and wiped the glass with a towel. The glass was dry when he set it down. Ten minutes later, the glass was wet and there was a water stain on the table. How did the table get wet?
Read the description and the question. Give students a moment to think about it, then go on to the next case.
Compare Evaporation & Condensation

10. Jasmine Sees her Breath
Jasmine stepped outside one cold winter morning. As she walked, she noticed little clouds forming when she breathed. She wondered why she could only see her breath on cold mornings and not in summer, when the air is warm. Why did Jasmine see her breath?
Read the description and the question. Give students a moment to think about it, then go to the next slide.
Compare Evaporation & Condensation

11. Condensation Water vapor in the air changes from gas to liquid
Heat transfers from water molecules to the environment
Water molecules lose energy when they condense
Glasses "sweat" when water vapor changes to liquid water
moist air
Introduce condensation and review its characteristics.
Compare Evaporation & Condensation

12. Answer Questions
Raymond poured himself a cold glass of soda. The glass was dry when he set it down. Ten minutes later, the glass was wet and there was a water stain on the table.
One cold winter morning, Jasmine noticed little clouds forming when she breathed. She wondered why she could only
see her breath on cold
mornings and not when the air is warm.
Have students answer the second set of questions.
Sample responses:
1. The table got wet because water vapor in the surrounding air condensed. Heat transferred from the water vapor molecules to the cold glass. When the vapor molecules lost energy, they changed to liquid water that collected on the outside of the glass and dripped down on the table.
2. Jasmine saw her breath because of the condensation of water vapor in the air she was exhaling. Heat transferred from the water vapor to the cold air around her. When the vapor molecules lost energy, they changed to droplets of liquid water that formed a visible cloud.
3. Both situations are examples of condensation. Both involve water vapor molecules losing energy to the environment and changing to liquid water.
Compare Evaporation & Condensation

13. Question 4 How did the table get wet?
Water vapor in the surrounding air condensed.
Heat transferred from the water vapor molecules to the cold glass.
When the water vapor molecules lost energy, they changed to liquid water molecules that collected on the glass and dripped down onto the table.
Compare Radiation & Conduction
Compare Evaporation & Condensation 13

14. Question 5 Why did Jasmine see her breath?
As she exhaled, water vapor in the air from her lungs condensed.
Heat transferred from the water vapor molecules to the cold air around her.
For question 6, students should say that both are examples of condensation. Both involve water vapor molecules losing energy to the environment and changing to liquid water.
When the water vapor molecules lost energy, they changed to liquid water molecules that collected in droplets to form a visible cloud.
Compare Radiation & Conduction
Compare Evaporation & Condensation 14

15. Evaporation vs. Condensation
Use your Evaporation and Condensation cards to compare and contrast the two processes.
Warm air
Distribute worksheet 23 and have students use the cards to complete the Venn diagram.
Compare Evaporation & Condensation

16. Evaporation vs. Condensation
Both
Water changes from liquid to gas (water vapor)
Water changes state
Water vapor in the air changes from gas to liquid
Heat transfers
Heat transfers from the environment to water molecules
Heat transfers from water molecules to the environment
Water molecules gain or lose energy
Water molecules gain energy
Sample answers will appear on keypress.
The environment gains or loses energy
Water molecules lose energy
Things "air dry"
Glasses "sweat"
Compare Evaporation & Condensation