Cloud in a Bottle
After a warm spell, we are delighted to watch rain clouds fill the sky. Did you know that a small replica of such clouds can be created easily at home with simple ingredients? Once you are conversant with the procedure, the DIY can be performed at science fairs. The Physics trick would be an instant hit with the visitors at the fair.
How to Make a Cloud in a Bottle
To form your own cloud in a bottle.
Warm water and smoke particles are introduced into a bottle to assist the formation of a cloud. The bottle is alternately compressed and relaxed to check for the conducive condition for the making of a cloud.
After pouring warm water and allowing smoke inside the closed bottle, a cloud will form on keeping the bottle relaxed. On squeezing the bottle, the cloud ceases to appear.
- 2-liter clear plastic pop bottle
- Warm water
- Fill the bottle 1/3rd with warm water and cap it.
- Squeeze the bottle and release it. Make an observation in your notebook.
- If you find water vapors condensing inside the bottle shake it to get rid of the water droplets.
- Uncap the bottle. Light a match and hold it at the opening of the bottle so that the smoke enters it.
- Drop the match inside the bottle and screw the cap on quickly. This traps the smoke within the container.
- Gradually squeeze hard and release the bottle. Repeat for 6 Put down your observations.
On release, you will see a cloud appear that disappears on squeezing the bottle.
Cloud was created due to the occurrence of favorable conditions.
3 conditions make formation of clouds possible.
- Water molecules
- Cool temperature and a pressure drop
- Particles that serve as condensation nuclei such as dust, smoke and air pollution, in general.
As the warm water evaporates, it adds water vapor to the air inside the bottle. These vapors need cloud formation nuclei where they can condense. It is provided by the smoke particles that enhance the condensation process. On squeezing the bottle the temperature rises and pressure increases that do not serve the purpose of cloud creation. On release, the pressure drops and the temperature falls that helps the homemade cloud to form. Note that the first observation you made cannot detect the presence of any cloud. That is because water vapor alone is not the requirement for cloud generation.
Kids will love the activity for its sheer thrill. It feels as if the vast expanse of the sky is captured in the realms of a single bottle. Preschoolers would need adult guidance with the matchsticks. Perform it in the lab to equip the older kids with the knowledge of the ideal gas laws. One of the parts of the law states that keeping the mass and volume of a gas constant, its pressure is directly proportional to the temperature as demonstrated above.
If proper measuring equipment is available, the results can be plotted in a pressure versus temperature graph for further research. The plot of the 2 variables should be a straight line by the gas laws. A proper theory, instructions, observations, analysis and diagram are instrumental for the completion of the lab activity.