Looking for Mr. C

Our house was previously owned by a widow and her daughter, whose last name begins with the letter C. We like digging holes in the back yard. In fact, the SIL Maker Club 2.0 just dug Hole 2.0 (a redesign of Hole 1.0, which the club made last year).

Borna from LAHS

Hole 2.0 used advanced technology, a 35 pound electric jack hammer.

 

Yes, Nathan jack hammers, while Sauyon supervises

Day One

Day Two

Smoke Machines and Lasers

As a step towards creating a laser harp, we experimented with a smoke machine and a laser pointer. To our surprise and delight, we discovered that the laser pointer will illuminate a slice of the smoke, revealing the turbulence.

We realized that the laser harp doesn't need to have discrete strings. Instead, it can be an entire pie slice, and you could slide your finger back and forth to have a continuous progression of sound.

Smoke from smoke machine, viewed with laser

smoke laser ping pong

Lissajous Figures

An old favorites of older scientists involves a special mode of some special machines, oscilloscopes. Everybody is familiar with the graph of a sine wave.

The same scopes can show two signals, such as ... wait for it ... two sine waves.

Each of the signals is the "y" value. The oscilloscope generates the "x" value: 0, .1, .2, .3, .4, ..., and displays the current value of y at that position in x. Hook up a time-varying sine wave or two, and you get the graphs above.

It gets interesting when you put the oscilloscope in X-Y mode. One input provides the y value, same as before. However, instead of the oscilloscope providing an upward counting x value, it uses the second signal for x. Now, x sweeps back and forth, say, according to a sine wave, and y changes up and down according to, say, another sine wave. The result? Lissajous Figures.

Peter's Right Arm - oh, and a Lissajous Figure