- Inform the students that they are going to create a model of a cloud in a bottle. Discuss with the students how clouds are formed.
- Discuss with the students how a model is used in science to study something. Ask students to describe how a model is like and different from the real object.
- Place a small amount of water in the bottom of both of the 2 liter bottles. The water should cover the bottom. One bottle is for the experiment and the other bottle is for the control.
- Have an adult light a match. Blow it out and quickly place it in one of the bottles.
- Smoke should enter the bottle.
- Remove the match. There should be a small amount of smoke in the bottle.
- Water droplets (a cloud) forms around the small dust particles.
- Place the lid on the bottle
- Swirl/shake the bottle to make the Swirl/shake the bottle to make the smoke disappear.
- Squeeze the bottle, hold it for a few seconds and then release
- Repeat several times
- When released, the bottle a cloud forms in the bottle
- When squeezed, the cloud disappears
- Squeeze the control bottle and observe the results
- Practice several times changing the amount of pressure needed to form a cloud.
- Repeat the procedure with the second 2 liter bottle. Add water and secure the lid. Do not add smoke.
- Squeeze the control bottle and observe the results
Conclusion
Water vapor is invisible as a gas. It can be seen when it condenses into water droplets – a cloud. When the bottle is squeezed more pressure is put on the inside where the water and dust particles are trapped.
A cloud appears when you release the pressure. It disappears when you squeeze. The sudden release, drop in air pressure, causes the water vapor to condense and form water droplets – a cloud. Once you have been able to create the cloud in the bottle, provide time for students to practice creating their own cloud in a bottle. Compare the two different bottles.
