# Water Cycle Unit Lesson 3, Evaporation

Subjects:

Math, Science, Social Studies

4

Title – Water Cycle Unit Lesson 3, Evaporation
By – Kristy Brooten
Primary Subject – Science
Secondary Subjects – Math, Social Studies
The Water Cycle Unit Contents:

Lesson 3

Concept being taught: Water droplets collect in water sources and evaporate into the air (affected by heat, surface area, air movement and water purity), becoming water vapor
*This concept constitutes lessons 2 and 3

I. Objectives
Content: TSWBAT demonstrate and explain the process of evaporation
Skill: TSWBAT observe, experiment, and determine variables affecting evaporation

II. Materials and Equipment
Water dishes and overhead from lesson 2, desk lamps, hair dryers, paper fans, food coloring, salt, cups of water (one per group), wide shallow dishes, narrow deep dishes

III. Detailed Lesson Outline
A. Motivation
Yesterday we watched a scene from The Secret Garden… Pull out your sheet of paper from yesterday. Share with your partner what inferences you made about evaporation.

B. Information Getting
What variables did we determine affect evaporation? Put up Evaporation overhead.
Yesterday we also made some guesses about what was going to happen to our water on the window sill. What do you think happened to water in the shallow dish compared to the water in the deeper dish? Let’s check it out and see what really did happen. What do you observe about the two dishes of water? Any other observations? What does this tell us about evaporation? Do we need to change our hypotheses from yesterday? Any other ideas? (affected by variable of surface area) Record on overhead.
What do you think happened to the water with food coloring mixed in? Let’s look and see. What do you observe about the water? Any other observations? What does this tell us about evaporation? Do we need to change our hypotheses from yesterday? Any other ideas? (affected by variable of water purity: debris in water does not evaporate with water) Record on overhead. We can see that debris like food coloring doesn’t evaporate with water. With your partner, discuss and write down your ideas: What other kinds of debris or substances won’t evaporate with water? Walk around to pairs and ask: Where can we see this going on in nature? (salt in oceans) How can this benefit our environment?

C. Closure
In our study of evaporation, we’ve discovered some important variables that affect evaporation. In groups of four, use your new scientific knowledge to find the fastest way to evaporate your cup of water. You can use any of the objects at your table. (Note: not all of the objects will help you.) You may come up with your own objects if you like. Look back at your notes if you need to. You might find it wise to use the scientific method/process as a model for your experiment. J Whichever group’s water evaporates first or whichever group has the least amount of water, whichever comes first, will “win” our contest. As class, discuss results: why did this group’s efforts evaporate water most quickly? Review variables of evaporation on overhead.

D. Evaluation
Write a short entry in your Science Journal explaining your group’s course of action and your reasoning for it. What variables of evaporation were you using? Did your methods work? Why do you think they did or didn’t?

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