July 16th, 2019

Praxis: Hand sanitizer and wind chill

By Medicine Hat News on February 9, 2019.

With the weather we have been experiencing this past week, I thought this experiment may be quite appropriate! I know that this extreme weather is nothing unusual for this part of Alberta, but we have not been “seasoned” yet! Usually there are a few days of cold weather to get us used to this and a -30 C would seem warm! All I can say is that we have been lucky this winter with the unusually “warmer” temperatures we have had to date. Nevertheless, I thought we should learn a bit about just how quickly these freezing temperatures can affect us, especially if the wind comes up. Let’s get started!

*Remember to ask an adult before doing this experiment.

Materials

– liquid hand sanitizer (not the lotion type)

– hands

Procedure

1. Squeeze a small amount of hand sanitizer in the palm of your hand and rub thoroughly on both the back and front of your hands.

2. Using your senses, how do your hands feel?

3. Allow your hands to dry.

4. Place another small amount of hand sanitizer in the middle of your hands and rub thoroughly.

5. This time, wave your hands through the air really fast.

6. Using your senses, how do your hands feel this time?

What is going on?

The first time you put the sanitizer on your hands, they should have felt a bit cooler, but nothing you could not handle. When you repeat the experiment and wave your hands through the air, you are simulating what it would be like if there was wind blowing on your hands. They should have felt much colder this time. This is due to evaporation. Evaporation is a cooling process and adding wind allows the process of evaporation to occur much faster and feel much colder. This is why when you hear the weather in the winter reported as with the “wind chill.” The wind causes moisture on your skin to evaporate much faster, making it feel much colder. It is also much more dangerous as your skin cools off at a much faster rate and you could get frost bite. Pay attention to the weather in the morning before you leave for school and dress appropriately!

Do not forget to register for the Drone Hack A Thon that will take place on Feb. 23 at Medicine Hat College. This free event is open to all students in Grade 9-12 in southeastern Alberta, but preregistration is required so we can ensure there will be enough materials for everyone. It will be a great opportunity for students to showcase their talents in creating ways to stop a remote-controlled drone, lightweight un-manned aerial vehicle from flying, including: helicopters, quadcopters, and small fixed wing aircraft less than 250g mass. Prizes will be awarded as well. I hope to see you there!

Patty Rooks is senior scientific consultant at 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.

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