Physical Changes: Liquids and Gases

Physical Change: when matter changes from one state (form) to another

Activity 1 - Liquid to Gas (Evaporation)

• Have students pour some water into a clear plastic cup or petrie dish.
• Next they should use a permanent marker to mark the water line on the outside of the cup.
• Place the cup in a sunny window.
• Observe and sketch a picture of the cup and liquid in their science notebooks/journals.
• Observe again each day and sketch or record the data.
• Ask the children the following questions? What state of matter was the water in the cup? (liquid) What happened to the water?  (It evaporated.) What state of matter is the water now? (gas - water vapor)

Activity 2 - Liquid to Gas (Evaporation)

• On a bright sunny day, give each child a half cup of water and a sponge brush or thick paintbrush.
• Take the children outside (yard, park, sidewalk, schoolyard).
• Have the children create imaginative pictures with water on the concrete/cement. They can draw a house, flowers, their name, etc.
• Have the children observe/admire their creative pictures.
• After a few minutes ask the children if they notice anything happening to their pictures. (They should be drying up as the water evaporates.) Ask the kids what happened to the water. Where did it go? What did it become? Why?

Activity 3 - Liquid to Gas (Evaporation)

• If you have access to an old fashioned chalkboard, have students wash the board with a sponge, then observe the board.
• Several minutes later have students examine the board. Continue until all the water has evaporated.
• Ask questions of students similar to the questions in activity 2.

Activity 4 - Liquid to Gas (Evaporation)

some clipart by www.graphicsfactory.com

• Have children help hang wet clothes on a clothesline. 
• As clothes start to dry ask questions similar to activity 2.

Activity 5 - Gas to Liquid (Condensation)

• Ask children to recall a time that they took a hot bath or shower. 
• Ask if the windows/mirrors in the room misted up. 
• Can they explain how this happened?

(When you fill a bathtub with hot water or run a hot shower, some of the hot water evaporates into a gas (water vapor). When the gas (water vapor) hits the cold window/mirror, it cools down and turns back into a liquid {water}.)

Activity 6

• Ask the students if they can think of more examples of water changing from a liquid to a gas or from a gas to a liquid. (possible answers: a teakettle boiling water, the Earth's Water Cycle, etc.) 

 

• Have the children sketch pictures of physical changes of matter in their notebook/journal (liquid to gas and gas to liquid)
• Older students can explain a physical change of matter and give several examples. 

 Activity 7

•  Here is a short video about the Water Cycle from the Scholastic website.

Click here: Water Cycle Video