The international radiation symbol (also known as trefoil) first appeared in 1946, at the University of California, Berkeley Radiation Laboratory. At the time, it was rendered as magenta, and was set on a blue background. The modern version used in the U.S. is magenta against a yellow background, and it is drawn with a central circle of radius R, an internal radius of 1.5R and an external radius of 5R for the blades, which are separated from each other by 60°. The trefoil is black in the international version, which is also acceptable in the U.S.
Reblogged from FYEAH, CHEMISTRY!.
June 04, 2012, 12:27pm
![thedailywhat:
Case For Sunscreen of the Day: This man is 69 years old.
He drove a truck for 28 years.
The premature aging from sun damage to the left side of his face is extensive enough to warrant a feature in the New England Journal of Medicine.
Trucker or not, don’t forget your sunscreen.
[gizmodo]
I’m always paranoid about getting a tan on half my face when I drive but it never passed my mind to consider the other effects of prolonged sun-light exposure.](http://24.media.tumblr.com/tumblr_m4y30jcfVY1qzpwi0o1_500.jpg)
