jtotheizzoe:

Every Cloud

Cloud week continues here on OKTBS! 

In 1802, pharmacist and amateur meteorologist Luke Howard drew up the first classification system for clouds, providing the origin of the Latin naming system we still use today. Meteorologists later developed a  system of cloud symbol line drawings in order to standardize weather maps.

Those symbols, the legends for which I’ve included above (for low, medium, and high clouds), strike me as a beautifully simple and artistic way to translate such a varied and unique phenomenon as clouds. They’re half zodiac, half typography. I just love them.

Can’t get enough of our fluffy sky friends? The great Every Cloud print also included above comes from artist and designer Joseph Perry, whose work I’ve featured before. If you’d like one for your own wall, Perry’s print available in a limited edition run of 100. Find it here.

Reblogged from jtotheizzoe

smartereveryday:

Wow… and actual volcano explosion shock wave.  Insane.  Hey!  We can do math on this!

The explosion happens at 0:12 seconds in, and the shock wave hits at 0:25 seconds.  13 seconds for the shock wave to hit the boat.

The speed of sound at sea level is 331.5 m/s (741.5 mph)

Velocity = Distance / Time

Therefore

Distance = Velocity x Time

Distance = 331.5 m/s x 13 seconds: = 4,309.5 meters

Ok.. so now we know the distance to the volcano… we can assume:

Density of the air at sea level = 1.224 kg/m^3

Speed of sound = 331.5 m/s as above

r = 4,309.5 meters from math….

If we had a calibrated microphone on the camera we could use the following equation from the paper "Generation and propagation of infrasonic airwaves from volcanic explosions"  to calculate the pressure in the volcano at the moment of explosion.

Acoustic Energy Equation

My raw notes for posterity.

idadarksky:

The Bortle Scale

The Bortle scale is a nine-level numeric scale that measures the night sky’s brightness of a particular location. It quantifies the astronomical observability of celestial objects and the interference caused by light pollution. John E. Bortle created the scale and published it in the February 2001 edition of Sky & Telescope magazine to help amateur astronomers evaluate the darkness of an observing site, and secondarily, to compare the darkness of observing sites. The scale ranges from Class 1, the darkest skies available on Earth, through Class 9, inner-city skies.

(Source: Wikipedia)

Reblogged from quantumaniac