Everyday science questions answered

By Ben Olson
Reader Staff

Editor’s note: Brenden Bobby was unable to contribute a column this week, so Reader Publisher Ben Olson is filling in for him.

It’s a beautiful thing to be curious. Sure, it killed the cat, but curiosity has guided many important scientific advancements over the centuries.

Since I’m filling in for Brenden this week, I thought I’d structure this column a bit differently and answer some everyday scientific questions you might have pondered a time or two.

Does blowing on hot tea really cool it down?

Even though your breath is warmer than the surrounding air, blowing on a cup of hot tea does actually cool it — a little. It all comes down to convection and evaporation.

As water molecules evaporate from the surface, it drops the average kinetic energy of the tea as well as the temperature. The evaporated molecules condense into steam over the cup, which lowers the liquid’s evaporation rate from the surface. Blowing replaces the hot, moist air with cooler, drier air, which helps to increase evaporation. Stirring will also help cool the tea by speeding up the convection process, bringing the hottest liquid at the bottom of the cup to the top.

This is a reason why it’s often best to leave a lid on a pan while boiling water, which traps more hot, moist air on the surface and results in the water reaching a boiling point faster.

How often should I reboot my computer?

This depends on what kind of computer you operate. A Windows computer should be shut down or, even better, restarted once a week or so with “fast startup” turned off to ensure it properly shuts down all processes and cleans up. Mac computers, on the other hand, tend to be a little more stable and may only need to be restarted with system installs or upgrades. Linux machines usually don’t need restarting very often.

One major benefit of restarting your computer is that it clears everything from memory, which might resolve problems like having applications crash.

Why do I feel my phone vibrating when it’s not?

This one actually has a name: “phantom vibration syndrome.” According to a study, nine out of 10 undergraduates said they felt their phone buzz in their pocket, but pulled it out only to see no one called or texted them.

Scientists aren’t 100% sure why these hallucinations happen to so many of us. 

One theory claims that our excessive smartphone usage, and the creeping sense that we need to make ourselves available 24/7, have conditioned our brains to overinterpret sensations such as clothing moving against our skin. The result is a lot of false alarms.

Why is leftover pizza so good?

Cold pizza is the best.

After devouring a few slices of ’za, you might remark the following day that it’s even better eating it for leftovers. This is because a night in the fridge gives the pizza flavors time to merge and mellow with one another. The pizza keeps its structure when cold, which helps the tomato layer prevent fat in the cheese from seeping into the dough base.

Food temperature also has an effect on taste perception. Warmer foods encourage heat-sensitive channels in the tongue’s sweet and bitter taste receptors to open wide, which sets off a chain reaction to send strong signals to the brain.

With colder food, the channels are barely open and the signals weaker. Salty and sour taste receptors are not affected by temperature like bitter and sweet, so cold pizza can taste a bit saltier and oftentimes, quite tasty.

Can you just cut the mold off of food and eat it safely?

It works with cheese, after all. But it’s not quite that simple.

Molds are fungi, some of which produce poisonous substances called mycotoxins, which may cause serious health effects, including tremors, fever, muscle fatigue and vomiting. Aflatoxins, produced by molds in cereals, spices and tree nuts, are some of the worst. They have been discovered to damage DNA and cause cancer, while large doses can damage the liver (this is why it’s never good to eat rancid nuts).

Molds thrive in moist, soft foods, like peaches. They also spread quickly through porous foods like bread, creating a network of roots invisible to the naked eye. If you think cutting off a moldy corner of bread makes the rest good to go, think again.

It’s only advisable to eat moldy foods that are designed to be that way, like blue cheese. But, there are some exceptions when you can safely slice away the mold, including with hard cheese, hard salami and firm vegetables like carrots. If you’re brave enough to eat moldy food, make sure you slice away a good margin for safety.

Are paper towels or electric hand dryers more hygienic? 

Sometimes this depends on where you’re using the bathroom; but, overall, scientists have failed to come up with a decisive answer for this question. What matters most, however, is washing hands regularly with soap and water for 20 seconds.

Do animals give each other names, or is that just a human trait?

Believe it or not, research suggests that other social species actually do give out and respond to particular “names” from fellow animals. 

Green-rumped parrot parents give their chicks a “signature call” or “name,” which is learned in the nest. Dolphins learn their own idiosyncratic “signature whistle” from their mother, and they can recognise and remember the “names” of other dolphins, too. One study found that male dolphins respond more strongly to the whistles of consistently helpful allies than to those of more erratic friends, showing that not only do they recognize names, but also know who’s a better friend.

Researchers also found that domesticated pets such as cats and dogs recognize their own names, and furthermore, can discern their owners’ voices from others.

Stay curious, 7B.