Source: We Are Star People!
Exploring the nature of the atom
• Uranium was discovered in 1789 by Martin Klaproth, a German chemist, and named after the planet Uranus.
• Ionising radiation was discovered by Wilhelm Rontgen in 1895, by passing an electric current through an evacuated glass tube and producing continuous X-rays.
• In 1896 Henri Becquerel found that pitchblende (an ore containing radium and uranium) caused a photographic plate to darken. He went on to demonstrate that this was due to beta radiation (electrons) and alpha particles (helium nuclei) being emitted.
Wonderful animation on how to calibrate an alcohol-in-glass or mercury-in-glass thermometer.
1. How could you make this experiment more accurate?
2. How could you use this experiment to calibrate other types of thermometers?
We all learn at school that pure water always boils at 100°C (212°F), under normal atmospheric pressure. Like surprisingly many things that “everybody knows”, this is a myth. We ought to stop perpetuating this myth in schools and universities and in everyday life: not only is it incorrect, but it also conveys misleading ideas about the nature of scientific knowledge. And unlike some other myths, it does not serve sufficiently useful functions.
There are actually all sorts of variations in the boiling temperature of water. For example, there are differences of several degrees depending on the material of the container in which the boiling takes place. And removing dissolved air from water can easily raise its boiling temperature by about 10 degrees centigrade.
To continue reading this article, go to the article on the University of Cambridge website here