Middle and High School … from a Montessori Point of View
You can get Google to give its assessment of a site’s readability, using a basic-intermediate-advanced scale, but for more granularity, you can use an online utilities like this Readability Calculator.
This recent post, for example, can be comprehended by students somewhere within the 8th and 12th grades.
I’ve been using the command line program SoX to generate tones for my physics demonstrations on sound waves.
Single frequency tones can be used for talking about frequency and wavelength, as well as discussing octaves.
Combine two tones allows you to talk about interference and beats.
SoX can do a lot more than this, so I though I’d compile what I’m using it for in a single, reference post. For the record: I’m using SoX in Terminal on a Mac.
To play a single note (frequency 173.5 Hz) for 5 seconds, use:
> play -n synth 5 sin 347
To save the note to a mp3 file (called note.mp3) use:
> sox -n note.mp3 synth 5 sin 347
The SoX command to play two notes with frequencies of 347 and 357 Hz is:
> play -n synth 15 sin 347 sin 357
and to make an mp3 file use:
> sox -n beat_10.mp3 synth 15 sin 347 sin 357
Play two sound tones that are close together in frequency and the sound waves will overlap to create a kind of oscillating sound called a beat.
Below are two tones: separated and then mixed — listen for the beat.
| Frequency | Sound File (mp3) | |
|---|---|---|
| Tone 1 | 347 Hz | 1m.mpg |
| Tone 2 | 357 Hz | 1m-357.mp3 |
| Mixed Tones (with beat) | 347 Hz + 357 Hz | beat_10.mp3 |
Interestingly, you can sometimes hear the beat as a third tone if the frequency difference is just right. The frequency of the beat is the difference between the frequency of the two tones.
The SoX command to play two notes with frequencies of 347 and 357 Hz is:
> play -n synth 15 sin 347 sin 357
to make an mp3 file use:
> sox -n beat_10.mp3 synth 15 sin 347 sin 357
Martha Herbert argues that diet and environmental toxins play a significant role in creating autism in an interview with Anne Strainchamps on To the Best Of Our Knowledge.
After much thought, I have come to the formulation that autism may be most comprehensively understood and helped through an inclusive whole-body systems approach, where genes and environment are understood to interplay.
— from Martha Herbert’s Website.
Herbert is the author of The Autism Revolution, and her website also hosts her scientific publications.
NOAA provides real-time (at least in the last 6 hours) images of the tropical Atlantic, which will often show the Inter-Tropical Convergence Zone (ITCZ) quite nicely.
They show images captured using visible light:
As well as infra-red:
Silvia Pelissero (aka Agnes-Cecile) brings a face to life in watercolor. (She has more, excellent videos on her YouTube channel).
I’ve not had much real musical training, but enough to know that I have a terrible ear for sound and can’t reproduce a note for anything. However, an informed source tells me that octaves represent the same note at different pitches.
The pitch is the frequency of the sound wave.
If one note has twice the frequency of the other, they’re said to be one octave apart. For example, click on the image below to listen to the same note at different octaves:
Or play the files:
| Wavelength | Frequency | Sound File (mp3) |
|---|---|---|
| 1 m | 347 Hz | 1m.mpg |
| 0.5 m | 694 Hz | 50cm.mp3 |
| 0.25 m | 1388 Hz | 25cm.mp3 |