Water Around Us: Visible and Invisible

by

Barbara P. Lorde


Objectives:

First and second grade students will be able to identify two forms of water .   Sometimes water is invisible when it is in the form of water vapor and water is visible in the form of water droplets.

Materials: 

1.  Three mirrors  accordingly to class size*handle carefully

2.  Chalkboard

3.   Three damp sponges 

Strategy and Activities:

Today,  we will look for visible water in the form of water droplets and invisible water  in the form of water vapor.

1.  Let students breathe onto a cold window or mirror.

2.  Explain that the droplets that form when they breathe out onto cold glass are from their own moist and warm breath.

    Warm moist air floats up or rises because it is lighter than heavier, cooler air.  When our moist breath turns into water 

    droplets on the mirror or window, we see the process of condensation happening.

3.  Tell students to put one of their hands up to their mouth and breathe on it.  It will feel warm and moist.  What makes your 

     hand feel warm and moist?  (It is the water and water droplets from  your mouth.)  Where does the moisture they feel on

     their hands go?  (This moisture turns into invisible water vapor and goes into the air.

4.  Ask students to wipe a chalkboard with a wet sponge.  Ask them to predict: a) Will the chalkboard dry by itself? b) How

     long will the chalkboard stay wet? c) Will the wet sponge dry by itself?

5.  Have one student wipe the chalkboard with a wet sponge.  Observe what happens and compare the results with the predictions 

     of the class.  Where did the water on the chalkboard go? (Into the air as water vapor.)  Help them to understand the  water

     droplets evaporated and became a water vapor that went into the air.  We are seeing evidence of the process of evaporation.

6.  Where will the water in the sponge go?  Observe and see the sponge seems to dry out over time.  Help them understand the

     wet water in the sponge changes into water vapor and evaporates into the air.  

Evaluation

1.   Asking the guiding question, "What are two different states of water and how are they formed?"

2.  Ask students where they can see water in the form of droplets.

3.  Ask students when they see evidence of invisible water or vapor.

4.  Discuss different forms of visible water vapor such as steam rising from a hot dinner or out of a tea kettle.

5.  Discuss when they see water droplets.  Examples may include: on the outside of a glass holding a cold liquid, 

    raindrops on a window, or droplets on a mirror when they breathe on it.

Vocabulary Words

Condensation- The process in which an invisible gas changes into liquid.

Evaporation- The process in which water droplets are changed from a liquid to a gas state.

Water Droplets- The liquid that comes from clouds as rain and forms streams, lakes, seas, and oceans.

Water Vapor- The invisible gaseous state of water.

*Careers Related to Lesson Topic*

Environmentalists, Scientists,  and Environmental Engineers

http://www.realtime.net/~raintree/gallery/water/water.htm 


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