12 Tone Equal Temperament

On a standard piano keyboard, one octave is divided into 7 whole tones: A, B, C, D, E, F and G. In between these tones are 5 further notes which can be called either sharps or flats: A# (Bb), C# (Db), D# (Eb), F# (Gb), G# (Ab). (whether it's a sharp of a flat doesn't really matter, the note has the same frequency, just a different name). This gives us a grand total of 12 notes in one octave. If you were to measure the frequency of a note, then measure the frequency of a note exactly one octa...

 Plank's Constant

In the year 1900 Max Planck wrote down an equation, E = hv, where E is the energy of a light wave, v is its frequency, and h is a constant which we now call Planck's constant. Planck's equation was the beginning of quantum theory. It said that energy and {22} frequency are the same thing measured in different units. Energy is measured in ergs and frequency in cycles. Planck's constant gives you the rate of exchange for converting frequency into energy, namely, 6 × 10–27 ergs per cycle. B...

 A Poem to Teach a Child

We live in an age of information. Too much information can swamp the boat of wonder, especially for a child. From a science book we might learn that a flying bat might snap up 15 insects per minute, or that the frequency of its squeal can range as high as 50,000 cycles per second. Useful information, yes. But consider the information in this poem from Randall Jarrell's "The Bat Poet": A bat is born Naked and blind and pale. His mother makes a pocket of her tail And catches him. He cling...