Now You See It, Now You Don't

TOPIC: ATMOSPHERE
LEVEL: Beginner

"Now You See It, Now You Don't"

CONCEPT:: Environmental conditions, temperature, density, and pressure, are continually changing.
STUDENT OBJECTIVE:: The student will observe the effects of evaporation through "painting" water on a shiny surface.
OVERVIEW:: In this activity, the students will use water to paint pictures on a shiny surface and to observe that over a period of a short time, the pictures will disappear. The students will be encouraged to think of all possibilities as to why the water disappeared. Evaporation will be introduced.
TEACHER TEXT:

PREPARATION TIME: 20 minutes

LESSON TIME: 30 minutes and at least three-five minutes follow up observations.

TEACHER PREP:

MATERIALS NEEDED:

STEPS TO FOLLOW:: 1. Take students outside to a flat, shiny surface. Smooth cement, clear plastic, saran wrap attached to a heavy piece of cardboard will do.; 2. Have students take their sponges of brush and paint a design on the shiny surface.; 3. Students will paint for 10 minutes.; 4. Let pictures stand alone for several minutes.; 5. Take class back outside to observe their paintings.; 6. Record student observations on chart paper or chalkboard.; 7. Continue observations until all the water has evaporated.

WHY?: As the water is heated, the molecules begin to move faster and faster causing them to break apart. As the water "disappears" into a gas, the water has now evaporated.

ASSESSMENT: Can the student communicate what they observed?: 4......Student is able to communicate that the water molecules in water move to fast that they break apart and evaporate into the atmosphere as a gas.; 3......Student is able to communicate that the sun heats the water and it disappears into the air.; 2......Student is able to communicate that water painting will disappear because it will dry out.; 1......Student is able to communicate that you can paint with water.

Last modified: Thu Apr 3 12:10:02 PST 1997