Praxis: Magic cans?
By Medicine Hat News on January 19, 2019.
This week I had a ton of requests for activities that involve air and aerodynamics and in particular Bernoulli’s Principle. I know that some of you may be scratching your head as Bernoulli is quite well known for his work in as a well respected physicist and was a pioneer in probability and statistics. Personally, I always relate his work to science, and in particular Bernoulli’s Principle. Let’s investigate further! *Remember to ask an adult before doing this experiment. Materials – ruler – two empty soda cans – flat sturdy work surface – masking tape – one package of plastic drinking straws Procedure 1. Using the ruler, measure one centimetre increments out on the table. Lay a straw at every centimetre mark. If you have a hard time remembering where the marks are, use masking tape to mark this off. 2. Place one straw on each of the marks. Try to make about 20 marks and have 20 straws on the table. 3. Place one can in the middle of the straws. 4. Set the other empty can beside the first one. Have some space between the two. 5. Take a straw, and blow one long stream of air between the two cans. 6. Observe. 7. What happens? What is going on? I absolutely love experiments that seem like magic, but are also teaching fantastic science concepts at the same time. This experiment, the unexpected happens. When you blow through a straw at something, it generally flies away, right? Well, in this case, that did not happen! The reason for this is that the air blowing through thestraw was moving faster than the air on either side of the empty cans. According to Bernoulli’s Principle, the faster moving air exerts lower pressure and the two cans are subsequently drawn toward each other. Do not forget, science fair is just around the corner. If you are looking for assistance in the classroom do not forget to call and book it as soon as possible. The Regional Science Fair will be on April 6. 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. 21-20
