Coming In Out Of The Radiation

It is a widespread belief that high-energy radiation cannot be felt, However recent experiments on mice at the National Cancer Institute in the U.S. have shown that these animals apparently test and shun a high-energy X-ray beam. When the mice were placed in a cage that was shielded to X-rays on one side, and open to them on another, the mice exhibited a strong preference for the sheltered side. The experimenters say they do not know how the mice detect the X-rays. The experiments were designed to rule out radiation-induced fluorescence or gas products as sensory cues.

Incidentally, talking about mice, have you heard the story of the research worker in psychology who had published an amazing result concerning white mice. A visitor asked him if he could see more of the evidence. The researcher replied, "Sure, there's the mouse."

The "Sun Gas" Returns To Stay

Helium today is making a dramatic comeback for a gas that was once considered down for the count. Discovered on the sun in 1868 and on the earth in 1895, helium was still a low-quantity item in the 1940's though it had gained some prominence as a non-inflammable lifting agent for blimps and airships. Today, helium helps weld many light-weight high-strength metals and is used in making semiconductors, processing Zirconium and Titanium and degassing metals. Liquid-fuel space rockets take advantage of helium's light weight (about that of oxygen) to get effective fuel tank pressurization and carry higher payloads. But helium's light weight and inertness are today amongst its more prosaic properties.

Helium is remarkably eager to absorb heat. Add its stubbornness against contamination by radioactive particles and you get a superior coolant for nuclear reactors, Liquefy it, and you have the coldest cold man knows—Just seven degrees shy of absolute zero! So that in the labs, helium is helping to slow molecular motions down to a crawl, giving us our first glimpses of many new phenomena.

Helium has a viscosity 8000 times less than water ; a very high heat and sound conductivity; and an extremely low ionisation potential. With researchers constantly seeking new ways to take advantage of all these properties, we observe that the "sun gas" has at last found its place in the sun.