Water Cycle Unit Lesson 2, Evaporation

Subjects:

Math, Science, Social Studies

4

Title – Water Cycle Unit Lesson 2, Evaporation
By – Kristy Brooten
Primary Subject – Science
Secondary Subjects – Math, Social Studies
The Water Cycle Unit Contents:

Lesson 2

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

II. Materials and Equipment
Wet sponges, dishes of water (shallow and deep), food coloring, The Secret Garden, TV & VCR, Evaporation overhead, overhead pen

III. Detailed Lesson Outline:
A. Motivation
At the end of every day, we wash off the blackboard with a wet sponge. Is the water still there on the board the next morning? Let’s check this out. Wipe wet sponge across the board. Where does the water go?

B. Information Getting
Take ideas from students as to what is happening to water. Any other ideas?
Introduce the term evaporation if it doesn’t come up.
How do you think we could make the water evaporate or disappear (go into the air) faster?
Put up “Variables of Evaporation” overhead and record students’ ideas. Try out suggestions:
What if we wave cool air on to it? What will happen then?
I brought some things with me today that I was thinking might help… What about this hair dryer? How do you think that might help speed things up? Try it out. Any other ideas? Cross out ideas if they don’t work, circle them if we need to do more research to find out if they work on not.
We have two dishes of water. What are the differences between the two? (shallow and deep) What do you think will happen if we put the same amount of water into each dish? Will they evaporate at the same rate? How might the difference affect evaporation? Fill dishes and set by window, observing throughout day and especially the next morning. Write down what you think will happen and why with your partner.
What if we add food coloring to the water?? Add food coloring to another dish of water. What is different about this water than the other water? How do you think that will affect evaporation? Will food coloring evaporate too, or just the water? Set dish by window, observing throughout day and especially the next morning. Write down your guess and your reasoning with your partner.

C. Closure
With your partner, come up with at least 3 examples of evaporation that you’ve seen in nature. In which instances did evaporation occur more quickly or more slowly? Why do you think that happened? What variables were affecting the process of evaporation? Share conclusions with class and review on overhead.

D. Evaluation
Replay rain sequence from The Secret Garden. Let’s take a look at this scene again that we watched yesterday. On a sheet of paper, tell me how evaporation might be occurring in this scene. What could make this take place faster? (What variables will affect the evaporation??)

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