Have students fill two identical jars half full with water and use a permanent marker to mark the water level on the outside of each jar. Cover the top of one of the jars with a piece of aluminum foil and place both jars in an area with direct sunlight. Children can observe the jars over a period of several days and note how the water in the jar that is not covered evaporates and the water in the jar covered with aluminum foil does not.
In a variation of the activity described in Section 1, have students take two identical glass jars and add roughly 1 tbsp. salt to one of the jars. Add an equal amount of warm water to each jar and stir the jar with the salt so that it dissolves. Students can mark the water level on the outside of the jars with permanent marker or masking tape and then set them next to one another on the counter. Students can predict whether the salty water or the fresh water evaporates quicker and observe the jars for several days to find out.
In an activity suggested on the Kids Science Experiments website, demonstrate evaporation to students through hanging wet clothes out to dry. Explain that warm water evaporates faster than cold water, and that water also evaporates more quickly from wet clothes on a windy day. Hang identical wet clothing items out on a sunny day and on a windy day. Children can observe how fast the wet clothes dry in these situations and how conditions such as warmth from the sun and wind effect the rate of evaporation.
In an activity that is suitable for young children, have each student put a dollop of hand sanitizer on their hands and rub them together in a motion similar to washing. The children can experience firsthand how their hands feel cool when they are wet with the hand sanitizer and also how, after several seconds, their hands are dry. The hand sanitizer evaporates from the hands of the students, demonstrating that evaporation is a cooling process. Have students move their hands through the air to make their hands feel colder. This demonstrates how wind speeds up the process of evaporation.