Google doodles

[9A]

April 4, 2020
Stay Home. Save Lives.

Wear a mask.
Save lives.

Wear a face cover
Wash your hands
Keep a safe distance

[9A]

February 18, 2015
Alessandro Volta’s 270th Birthday

​

Experimenting with different metals and solutions, Volta ended up creating the first electric battery: the Voltaic Pile, a stack of alternating metal discs separated by cardboard and cloth soaked with seawater. But what made this battery so remarkable was that it was easy to construct out of common materials and enabled experimenters for the first time to produce steady, predictable flows of electricity. Within just weeks it inspired a wave of discoveries and inventions and ushered in a new age of electrical science.

[9A]

November 29, 2017
Christian Doppler’s 214th Birthday


When a fire engine approaches, the siren gets louder as it comes closer, taxing your eardrums as it whizzes past, and fades into the distance. What causes this difference in volume?
The answer was proposed by Austrian mathematician and physicist Christian Doppler in 1842 in a phenomenon since documented as the Doppler Effect, a concept that applies to both sound and light, in addition to other phenomena.

Simply put, sound is generated in ‘waves.’ As the source of such waves moves closer, the waves themselves take less time to reach you. They hit you with increasing frequency, making the sound more intense. As the source moves away, the waves start to spread out, and the sound becomes weaker.

The Doppler effect also explains why stars in the sky appear to be of different colors. As a star approaches the earth, wavelengths compress and the star appears to be bluer in color. If the converse happens and a star is moving away from us, it appears redder.