## Introduction: Magnus Glider

Use curveball physics to make this glider fly!

This is one of the 48 projects for our Instructables: Made In Your Mind (IMIYM) exhibition at the Children’s Museum of Houston showing from May 26, 2012 - November 4, 2012. Produced in partnership with Instructables, IMIYM is an exhibit where families work together to build different fun, toy-like projects that help construct knowledge and skills related to science, technology, engineering, and mathematics while instilling a “do-it-yourself” attitude in kids so they feel empowered to explore, tinker, and try to make things themselves. To learn more, check out the article here.

For this project, we were inspired by the \$0.05 Toy Hovercraft/Helicopter Instructable created by Hoopajoo, but there may be others on Instructables that are also similar. Often, the materials and process for building our projects are designed for use with a large number of visitors (we see over 800,000 annually) and the need to ensure safety in a mostly non-facilitated environment. So, yes, many of these projects have room for improvement in both materials and methodology, which is PRECISELY what we want to encourage the kids to do. So please do share your ideas for improvement and modifications!

## Step 1: What You Need

We are selective in our materials for cost, ease of use, and safety due to our high traffic (800,000 visitors annually). So, for our purposes, this design worked best. But you may have other ideas - please share!
• 2 – 12 oz. Styrofoam cups
• 4 – Rubber bands, #19

## Step 2: The Video

We offer optional video segments of each step for this project in the actual exhibit. Here is a compilation of all the steps.

## Step 3: Step 1 - Build the Glider

Tape the bottoms of the cups together so that the open mouths face away from each other. Make sure the cup bottoms line up evenly with each other. Use several wraps of tape.

## Step 4: Step 2 - Make a Rubber Band Chain

Take two rubber bands and loop one around the edge of a second, then back through itself. Pull to make the knot tight. Repeat to connect the other bands to the chain.

## Step 5: Step 3 - Wrapping

Use your thumb to hold one end of the chain in the center of the cups. Stretching the rubber bands, but not so tight they damage the cups, wrap the chain around the taped part of the cups while holding onto the end of the chain. Once almost completely wrapped, hook the other end of the chain over your other thumb so that the chain is coming out under the cups. The video may be helpful.

## Step 6: The Launch

To launch, hold the hand with the cups behind the other hand. Make sure the rubber band chain is coming out under the cups. Aim your forward hand up in the air, pull the cups back (unwind a little if needed) and let go of the cups. It won't fly high, but rather glide gently to the ground. It is especially cool if you do it at the top of the stairs or off a balcony!

The way we explain this in the Museum is that this glider uses the Magnus Effect to give it the slow, gentle glide you see. As the cups spin through the air, they create a sort of “whirlpool” of air around them. This “whirlpool” of air exerts an upward force on the cups. Baseball pitchers rely on this same effect to throw a mean curveball!

The next step would be to try to build their own version. What if:
• They used more cups?
• They used different sized cups?
• They used different size rubber band?
• They used longer or shorter rubber band chains?
• They used different kind of cups (plastic, paper, etc.)?