Science Smarts: What makes a curveball curve?
By Patty Rooks on May 18, 2024.
It is that time of the year – baseball season is here! What fun it is to sit in the stands and cheer on my favourite team. There are so many amazing youth teams in our communities and what a great way to get outdoors and enjoy the afternoon. Of course, when I am watching, my mind does wander a bit and lately, I have wondered what happens when a pitcher throws a curveball. Of course, I am going to turn to science and figure this out. Let’s get started! *Remember to ask an adult for help before doing this experiment. Materials – Sheet of paper – Scissors – Ruler – Pencil Procedure 1. Using the ruler measure a strip 3 cm x 30 cm. 2. Cut out the strip of paper. 3. Hold the strip of paper to your bottom lip. 4. Blow as hard as you can onto the surface of the paper. 5. Observe what happens. What is going on? Blowing on the strip of paper caused the paper to flip up. The force of your breath, or the stream of air coming out of your mouth “pushed” against the bottom of the paper. Because you were holding the paper with it hanging down, the force of your air caused it to rise up. What is happening here is a scientific principle called Bernoulli’s Principle. Bernoulli’s Principle states that “as air (or any fluid) moves, it creates a region of low pressure. Low pressure has less “pushing force” than air of high pressure”. When you blew across the upper surface of the strip of paper, you created low pressure. At the same time, air that was beneath the strip kept its normal pressure. The normal pressure is now greater than the reduced pressure at the top, resulting in the strip of paper being pushed up. Something similar happens when a baseball is thrown. When a baseball travels through the air, the air flows around the ball. When the pitcher throws a curveball, part of the spin on the ball is in the direction of the flow of air and part of it is in the opposite direction. When the flows of air are in the same direction, it speeds up the ball. Just as you saw in this experiment, as the speed increases, there is a small decrease in air pressure on that side of the ball and the ball moves in that direction. At the same time, the higher pressure is also pushing the ball on the other side. This results in a curveball. 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. 22-21
