Photo: Steven Goodwin [Flickr]
Every kid knows that if you place a ruler over the edge of a desk and flick it, it'll "twang" - and by changing the amount of the overhang, you'll change the pitch.
Steven Goodwin of Blue Dust blog turned this basic idea into a fun (and cheap!) science project you can do with your kids: make a "Rule Organ" out of a set of rulers:
We start by determining the length of each overhang. By knowing how much is needed for the lowest note, C in our case, we can calculate the others mathematically. Finding the lowest note is done in typical school kid fashion by experimenting, unless you have a keyboard, guitar, or other musical instrument and an extra pair of hands, er, to hand.
You will notice that some lengths do not produce notes at all. Very short distances just produce a click, while very long ones make no sound at all. To make a complete octave, the overhang of the lowest note will need to be twice as long as the shortest (highest note), so if the rules you're using only make sounds between 5cm and 8cm you won't get a full octave.
TIP: Hold the rule to the desk as tightly as possible to produce the best audio fidelity (read: twang) possible.
Comments (6)
http://www.youtube.com/watch?v=jFG9uR9Q_L4
Again, very cool.
I've had a bunch of these pics for a while, and have been trying to track down the source. First thing is, they seem to be cg in origin, not the grainy black and white pics that would have been.
The Ka -7 did exist. It was smaller than this, and an utter disaster. It vibrated so badly that its first test flight was abandoned just five metres (15 feet) off the ground. After major modification it flew again.. And crashed.
But if anybody can give the true origins of these pictures, I'd be grateful... Oh.. and don't say "Dark Roasted", they also confuse fiction with reality. The curse of the web, if you see it on the web, it MUST be true.