You can use snow or shaved ice to illustrate evaporation. Label two clear plastic cups per student with the student's name. After a snowfall, take your students outside to collect snow in the cups. They should bring the cups of snow inside and cover one of the cups with plastic wrap and a rubber band to hold it in place. Have them set the cups where they won’t be bumped. Ask the children what they think will happen to the snow. Have them check hourly on the snow. Tell them that the warm air inside the classroom melted the snow. Check on the cups daily and have the children mark the change in water level. Explain that the water in the uncovered cup evaporated.
Show your students the change from solid to liquid to gas. Put an ice cube in a small pan and put it on the stove on medium heat. As the ice cube begins to melt, show the children what is happening in the pan. When the ice cube has fully melted into water, show the children the ice cube is gone. Continue to heat the water in the pan. Students will notice steam coming out of the pan. Ask the class if they know what is happening. Explain the heat from the stove is causing the water to turn to gas and evaporate. When the water has fully evaporated, show the students the empty pan.
After a rainfall when the sun is shining, take your children outside to find a puddle in the school parking lot. Use sidewalk chalk to draw around the outline of the puddle. Contact the school custodian to ask him to put up several orange cones or saw horses around the puddle to prevent cars or individuals from going through it. Check on the puddle periodically and draw the new outline. When the puddle has disappeared, talk to the children about evaporation.
Have the students watch as you mix salt into two cups of water until no more salt will dissolve. Pour the saltwater into a small pan and heat it on medium heat. The children will see the water evaporating out of the pan as steam. When the water has fully evaporated, let the pan cool for ten minutes. Show the students what is left in the pan. Explain that the water evaporated from the heat, but the salt did not and was left behind.