Pulleys can be heavy, like a block and tackle, or light, like those used in Venetian blinds.
Devices intended to complete a simple task using a complex series of sequential cause-and-effect actions are usually called Rube Goldberg machines, after the early 20th century comic artist. A Rube Goldberg machine often involves actions of living creatures, dropped bowling balls, pulleys, levers, springs and ramps. Most of the parts of a Rube Goldberg machine were simple machines like pulleys, levers, inclined planes or springs. In this case, the pulley, inclined plane and lever can be put together sequentially to pop a balloon.
Instructions
1. Slide the narrow pencil through the bobbin, ensuring the bobbin spins freely. Tie one end of the 1-foot string to the pencil, then loop it over and tie the other end to the pencil on the other side of the bobbin. Slide the tension rod between the string and the pencil so that the pencil is suspended on the rod.
2. Mount the tension rod in an empty doorframe, tightening until it stays put when you tug it.
3. Place the slide below the tension rod, with the flat part of the seat directly below the pencil, so that the foot of the slide juts into a room.
4. Using double-sided tape, firmly affix one end of the 5-foot string to a narrow end of the cardboard rectangle. Place the rectangle on the flat top of the slide with the stringless end just over the inclined plane's beginning.
5. Thread the free end of the string over the bobbin to make a pulley.
6. Attach string to the balloon. Using a tack, suspend the string from the ceiling so that the balloon hangs directly over the foot of the slide, about 2 feet off the ground. Cut off any excess string.
7. Place the weighted box about 1 foot in front of the slide's base. Put the non-skid plastic mat flat on top.
8. Use double-sided tape to affix the other tack to one end of the yardstick, point side out. Lay the yardstick horizontally over the box so that the tack end faces up and the non-tack end is about 6 inches from the slide. This is your lever.
9. Place the basketball at the top of the slide and on top of the cardboard. Make certain the pulley string is uncovered and moves freely.
10. Pull the loose end of the pulley until the cardboard tilts and dumps the basketball. The ball will roll down the slide, hit the yardstick and flip it upward. The tack will impact the balloon, popping it.
Tags: Rube Goldberg, double-sided tape, foot slide, , inclined plane