Wednesday, 19 April 2017

Sugar sweet colors

The beautiful colors we observe under the polarizing microscope have to do with the "optical activity" of - in this case - fructose.

Light is an electromagnetic wave phenomenon, in which the direction of vibration is perpendicular to the direction of propagation. An electric and a magnetic vector vibrate thereby at right angles relative to each other. In a 'normal' light, such as daylight, all directions of vibration are present at the same time. Polarized light, is light wherein only one direction of vibration in the beam is present.

Thursday, 6 April 2017

It’s green and it has tentacles!

Hydras are tiny animals, which are closely related to jellyfish. Green Hydras live in shallow fresh water, such as streams, rivers, lakes, and ponds, where they attach themselves to plants, stones, twigs, or other objects. Unlike their jellyfish cousins, they don't like to float around. They are very common. A Green Hydra can grow up to 30 millimeters long, but usually they are less than 15 mm.

One hydra can have anywhere from four to twelve tentacles. Each tentacle has tiny bumps, called nematocysts. The nematocysts release a material that paralyzes