Disappearing Puddles

Show how the sun and wind can turn water into vapor with sidewalk chalk and a sunny day.

Materials:

  • Sidewalk Chalk

  • Safe concrete area that won’t be disturbed during for an hour or so

  • Sunny warm weather

  • Cup of water

Take the class out to a safe area with concrete on a sunny warm day. Have the students stand in a circle . Pour about a cup of the water on the concrete to cover an area. Let it settle enough so that the wet area is obvious.

Outline the wet area with the sidewalk chalk. Ask students to predict what they will see if we return later.

In an hour or two the class returns to the same site. Students describe how the chalk is still recognizable but the water is gone. The wind and the sun turned the water into vapor. If there are clouds, it’s not untrue to speculate that some of the water is out there.

Students return to the class and discuss what we did and what we learned. Write down what they say. Students answer what we did and what we learned in their journals. When a student finishes they read what they wrote to three other students.