If your kettle has just carked it, it can be tempting to use the microwave to quickly heat up some water to make tea. If you do that, though, you're quite likely to end up with a terrible tasting cuppa. Here's why that happens.
Slate's Nadia Arumugam explains why microwaving water doesn't result in anywhere near as satisfying a cup of tea as using a kettle. It comes down to a matter of convection:
Microwaves don’t heat water evenly, so the boiling process is difficult to control. Microwave ovens shoot tiny waves into the liquid at random locations, causing the water molecules at those points to vibrate rapidly. If the water isn’t heated for long enough, the result is isolated pockets of very hot or boiling water amid a larger body of water that’s cooler.
The result when you drop a teabag or infuse some leaves in that water is that you get an unpredictable and terribly uneven chemical reaction, which can lead to a terrible tasting cup of tea. This gets back to a concept we've covered at Lifehacker previously, which is that tea works best when it is introduced to water which is actually boiling.
The one exception to this appears to be green tea, which can work with lower temperatures to produce a pleasing taste. But for other types of tea, if the kettle is kaput, stick a saucepan on the stove, and take your time. A good cup of tea is worth it.