Now you can't help but introduce this demo by playing that Miley Cyrus song. ;)
In my last classroom I was able to drill into the supporting I-beam in the
ceiling and insert a large threaded rod, with Loctite and several locking nuts.
I cut a piece of plywood to be the same size as that ceiling tile, with a hole
in it at just the right spot. This prevents the threaded rod from moving side
to side while the pendulum swung. The plywood is placed on top of the ceiling tile so the ceiling looks uniform from beneath. An inconspicuous eye hook is all that you can
see from the ceiling when everything is placed. The support should easily hold
200 pounds so it also hangs a punching bag during my momentum unit.
In my current English-room-turned-science-room this set-up wasn't going to
work. For one I'm probably moving again next year so I try not to make too many
holes. The ceiling is also not as strong. About half the room has a dropped
ceiling covering duct work, the other half has exposed beams in terrible
strategic positions and wood slats across the rest. I thought I was destined to
go back to the videos I used to use before I realized there was a support beam outside my
Since I was in a new
room, making a new set-up, I decided to make a new pendulum ball. I had shared
a bowling ball pendulum made by another teacher, so I decided to make my own. I
drilled the biggest hole I could using our drill press at school but it wasn't
quite big enough for the eye hook I wanted to use so I had to take a rat tail
file to it. In retrospect, as can be seen to scale with the bowling ball, it
might be a bit big. I filled the hole with two-part epoxy and used an extra 6'
dowel I had around to tighten it with the help of a student and an aid. Simple
machines work kids. ;) We tightened it until we heard a small crack. The crack
filled with epoxy and set quickly. A few hours after it cured I tried swinging
the bowling ball around, trying to start and stop it quickly to test the
connection at high forces.
The hardware in the
upper right attached to 1/8" steel cable to make
the pendulum. Given the
arrangement of my outside beam I have to be able to loop the steel cable around
it. When we did the demo everything stayed together! The only hiccup was
getting paint flecks from the peeling paint on the wood support beams in my