Magnus Effect Glider
Have science fun as a family! Complete activities with parental supervision.
- Two disposable cups (any size or material)
- Four rubber bands
- Tape the bottoms of the cups together, making sure that the bottoms line up with one another. Go over the seam several times with tape to make sure it will stay together in flight.
- Take the rubber bands and chain them together. Loop one around the edge of a second and then back through itself. Check out the pictures, if that helps! Pull tight—if it stays together, you’ve got a good chain! Repeat with the other rubber bands.
- Using one of your thumbs, press the end of the rubber band chain to the center of the cups.
- Wrap the rubber band chain a 2-3 times around the cups, stretching slightly to increase the tension. The rubber band chain should be coming out underneath the cups, not above. Once it is wrapped, hold on to the end—don’t let go yet!
- To launch, hold the wrapped cups in one hand and hold the end of the rubber band chain in the other hand. Pull the cups back a little and then let go!
- The cups should glide slightly up and gently away from you—if they don’t, keep practicing! It’s tricky to master, but super satisfying when you do.
- Be sure to take a picture or video to share in the Facebook comments on the Buffalo Museum of Science or Tifft Nature Preserve pages!
What’s it all about?
Newton’s Third Law of Motion states that every action has an equal and opposite reaction. During launch, the rubber band forces the cups forward…. with a backspin! The backspin pushes the thin layer of air around the cups down. As the air around the cups is pushed down, the cups are forced up!
This phenomenon known as the “Magnus effect” is what baseball pitchers use to make curveballs…. curve! By varying the direction and rate of spin of a pitched ball, a pitcher can create a variety of wildly veering pitches: curveballs, fastballs, screwballs, and sliders.
- Make some design changes and see how it works! Try different types of cups (paper, plastic) or even different sized cups. What happens when two cups are different sizes from each other? How can you add even more cups? Try it out and let us know what you discovered!