Science Smarts: We’re building clouds today!

By Patty Rooks on July 13, 2024.

WOW, to say it has been hot, I think would be an understatement! Personally, I prefer it to be a bit cooler and often seek out the shade, or look up to see if a cloud may be coming over to provide a bit of relief from the intense heat when I am out an about. Now that I think about it, there has not even been a cloud in the sky for days…hmm…this makes me wonder, could I make my own? Just how are clouds formed? Let’s get started!

*Remember to ask an adult before doing this experiment.

Materials

• bicycle tire foot pump

• cork

• empty 2L pop bottle

• 70% rubbing alcohol

• safety glasses

• metal inflation needle (from the bicycle pump)

• science helper

Procedure

1. Put on your safety goggles.

2. Make sure your cork fits in the pop bottle. It should be quite snug. You can purchase different sizes, so be careful that you measure correctly.

3. Have an adult assist you in pushing the metal inflation needle through the cork. It should be through just enough so you can pump air out of the end.

4. Attach the pump to the inflation needle/cork.

5. Pour enough rubbing alcohol in the pop bottle to cover the bottom. Swirl it around all the sides ensuring it is all coated.

6. Put the cork in the bottle.

7. Holding the cork firmly in place, pump the bottle up – it may take ten or fifteen pumps…the bottle will be really firm to the touch.

8. Remove the cork.

9. Observe.

What is going on?

Did you know that there are water molecules in the air around you – even if it is not raining? These invisible drops of water are actually called water vapour. The air you are pumping into the bottle is actually forcing the water vapour present in the bottle to squeeze together really tightly. They are just kind of hanging out there and then all of a sudden – WOW! When you pop the cork out of the bottle, you are releasing all of that pressure rather quickly allowing the air to expand. As this happens the temperature of the air cools down or condenses and you are able to see the cloud.

Clouds are quite complex to understand, but I will try to simplify it here for you. Basically, clouds forms when air which is warm and moist rises, cools and then expands high up in the atmosphere. This water vapor condenses to form tiny water droplets which in turn start the entire process of forming a cloud.

Patty Rooks, senior scientific consultant PRAXIS, “Connecting Science To The Community.” Contact Praxis at praxis@praxismh.ca, http://www.praxismh.ca, Tweet or follow us @PraxisMedHat, or friend us on Facebook. Address: 12 826 11th Street SE, Medicine Hat, AB, T1A 1T7 Phone: 403-527-5365, email: praxis@praxismh.ca.

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