Your grandma did it and your mom does it all the time, so should you continue the tradition? From salting boiling water to grinding ice, read on for the truth about four common household hints...
Myth: Adding salt to water makes it boil faster.
The Truth: Nope. Salted water actually takes a little bit longer to boil, since the salt raises the boiling point from 100°C to around 106°C. But salt water does boil hotter because when sodium chloride (salt) attaches to water molecules, it releases gas bubbles which increase movement in the water and therefore the temperature. So although you will wait a little longer for your salted water to boil, it will cook your pasta a little faster. Cool!
Myth: Store batteries in the refrigerator so they'll last longer.
The Truth: Short answer: not really. The chemical reaction within the battery (the one that creates an electrical charge to power your devices) is affected by temperature, and cold temps do slow that process; however, contrary to popular belief, batteries don't generate energy unless they're in use, so there's not much point in chilling a resting battery. In fact, until your refrigerated battery returns to room temperature, it won't be able to generate much electricity at all (just try starting your car on a freezing morning). The maximum recommended temperature for a battery is around 77°F, so drawer storage should be just fine for most people.
Myth: Microwaving a sponge kills bacteria.
The Truth: Yes! But it's a little more complicated than 10 seconds on high. Studies show it takes two full minutes for 99% of germs to bite the dust. Double that time to four for complete sterilization. Make sure your sponge is damp (microwaves work by heating water molecules) and, depending on how often you use it, nuke it every few days as a rule of thumb.
Myth: Grinding ice cubes will sharpen your disposal's blades.
The Truth: Sort of. There's no way to really sharpen the blades, but grinding up some ice cubes every now and then does clean them by knocking off built up residue, helping them to function more efficiently. Run some cold water, grind the ice for about a minute, and you should be in business.
Re-edited from a post originally published 7/21/2013—JH