Air compressors are often loud, raucous machines – but they don’t have to be. [Eric Strebel] built a remarkably quiet compressor using parts salvaged from an old fridge. After several years of use, it ...

For astronauts to go on long missions to the moon or Mars, they need a refrigerator. But today’s fridges aren’t designed to work in zero gravity or upside down if oriented that way when a spacecraft ...