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...courses and qualifications A crystal set is the most basic type of radio receiver. It is capable of receiving AM (amplitude modulated) transmissions, which are generally found on the long, medium and short wave bands. The magic of the crystal set is that no power source is required; a tiny fraction of the transmitted signal provides sufficient power for the signal to be...

...courses and qualifications [vial of gold] Why is gold so expensive? Gold is an unusual metal in that it predominantly exists in the Earth’s crust as the element (so-called ‘native’ gold); that is, it’s not chemically combined with other elements. Silver and copper are the only other metals naturally found in their elemental form. Gold is a relatively rare element,...

...course, as the publicity of Hidden Figures. But for a long time women didn’t have such visible role models working in science or space. [A photograph of Katherine Johnson seated wearing her newly awarded Presidential Medal of Freedom. She is sat in the centre of the photo with a man sat behind her. She wears a black blazer and orange blouse underneath, with small medals...