Should you believe everything you hear? I was relaxing for a few moments, reading random websites, when a list of “old wives’ tales” caught my eye. I give full credit to www.snopes.com for their informative and entertaining work.

1.  Should you tap the side of a soda can before opening it, in order to prevent its contents from foaming all over your hand?

2.  Do you only use 10% of your brain?

3.  Can you determine the temperature by counting cricket chirps?

4.  Is the Great Wall of China the only man-made object visible from the moon?

5.  If you are kidnapped, blindfolded, and taken somewhere far away, can you determine which hemisphere you are in by which way water spirals as it does down the drain?

6.  Should we be cautious around water that was boiled in a microwave oven, in case it suddenly “explodes”?

Which ones did you answer yes to? Let’s have some fun, and maybe you’ll pick up a bit of healthy skepticism.

Answers:

1.  Unfortunately for those of us who get food stains on their clothing within minutes of getting dressed in the morning, tapping a shaken can of soda won’t keep it from spewing its contents all over the place. The only practical solution is to let it sit a while before opening it.

2.  Hopefully, you are using all of your brain. PET scans and MRIs provide ample evidence that every part of our brains gets involved in our day-to-day lives. Of course, that’s not to say that we can’t make better use of what we’ve got!

3.  What? You don’t own a cricket thermometer? The Old Farmer’s Almanac explains that counting the number of chirps in 14 seconds, and adding 40 to the total, will give you the temperature in degrees Fahrenheit.

There are only two drawbacks to this method. First, you’ve got to have crickets around. Male crickets, to be exact, since they’re the ones doing the chirping. (It’s their way of acting macho and defending their mating territory.) And second, it’s only useful down to 55 degrees or so, because cold crickets sulk rather than chirp. Now next time you go camping, you can impress your tent-mate by telling them the temperature.

4.  First-hand accounts from orbiting astronauts describe the Great Wall of China as barely visible from a low earth orbit, much less the moon. In fact, nothing man-made is visible from the moon. Kind of humbling, isn’t it?

5.  Sorry, you’ll have to figure another way to escape. While the Coriolis effect does influence ocean currents and weather patterns, water in a sink or toilet is much too small a mass to be influenced by such a weak force. It’s more likely that minor imperfections in the basin holding the water will determine which way it flows out.

6.  This phenomenon does occur, but requires such perfect conditions that it’s highly unlikely you’ll ever encounter it.

Basically, because the water in the microwave is sitting perfectly still, it may get super-heated, and yet not boil. However, the tiniest nudge will disrupt all those excited molecules, and the water will erupt out of its container. Any impurities in either the cup or the water, or any movement of the cup as it heats, will eliminate the danger.

You can see a mini version of this when you add a spoonful of sugar or a teabag to your hot water. It bubbles furiously around the introduced particles. If you of a paranoid bent and want to make super-sure you don’t get burned, just leave something—a stir stick, teabag, or non-metal spoon—in the cup of water as you heat it.

You can find more wonderful facts at www.snopes.com/science/science.asp.