Sometimes science writers struggle to convey the magnitude of the thing that they are trying to explain. Carl Sagan fared better in that struggle than most as this book of his collected writings will attest Our next Science Book Club choice is Profiles of the Future by Arthur C Clarke which Tim will review on March 4 Nearly all organic molecules absorb infrared and ultraviolet light. If the planet's ambient light was confined to either, everything would be black. Plants absorb red and blue light, but reflect green, which explains the colour of foliage. Anthocyanin is the pigment of roses and violets. In acid, it turns red and in alkaline environments it reflects blue. Roses are red and violets are blue because their pH is different. Middle C is 263 Hertz, or 263 waves of atmospheric compression and attenuation every second, and even someone stone deaf could identify Middle C, at least with an amplifier and an oscilloscope. So ignore that question about the sound of a tree falling...