Making Coffee

You can see that a coffee maker is about as simple as an appliance can get. Here's how it works:

1. When you pour in cold water, it flows from the bucket through the hole in the bottom of the bucket and into the orange tube.

2. The water then flows through the one-way valve into the aluminum tube in the heating element, and then partially up through the black tube. This all happens naturally because of gravity.

3. When you turn on the switch, the heating element starts heating the aluminum tube, and eventually the water in the tube boils.

4. When the water boils, the bubbles rise up in the black tube. What happens next is exactly what happens in a typical aquarium filter: The tube is small enough and the bubbles are big enough that a column of water can ride upward on top of the bubble.

5. The water flows out the end of the black tube to drip into the coffee.

This boiling-water pump, by the way, is the same mechanism that drives a percolator-type coffee machine.

As you can see, there is no mechanical pump of any type and really no moving parts (except for the moving portion of the one-way valve). This makes coffee machines extremely reliable.