Every so often I hear someone say the cliche phrase "If it's so great and wonderful, why hasn't someone already invented it yet?", and when I hear that phrase, I can't help but think of the fact that the things we have are only there because one or several people had tirelessly worked to conceptualize, design, prototype, test, (possible re-build/adjust and re-test), manufacture, distribute, market, and sell them. It's a very long and tiresome process that continues to mitigate even the best solutions from being bought and implemented. There's a lot of toil, politics, resource acquisition/management, teamwork, and other things that need to be gone through before even the simplest things can hope to find themselves in the service of others.
Anyway, here are some inventions which are so simple that some of the earliest civilizations should have invented them long ago:
1. The Pulser Pump - Probably one of the simplest water pumps that mankind has ever made. The pump was invented in 1989 by Brian White. The device uses buoyancy, air, and water to lift water many times higher than from where it fell from.
2. The Hydrautomat - The Hydrautomat is a device that uses air and water pressure to lift water. The device is similar to Hero's Fountain, but it can actually drain and refill itself: lifting water each time it drains or fills).
3. The Fluidyne - The Fluidyne is a device that uses a difference in temperature to cause the fluid inside of it to oscillate. These oscillations can then be used to pump water, compress air, or another purpose.