How Come?

How does a scab help a cut or bruise?

Kathy Wollard — Sun, 17 Jun 2012 01:26:11 +0000

How does a scab help a cut or bruise? asks reader Nia Ramsey.

When a scrape or a cut makes an opening in the skin, it’s a kind of body-wide emergency. An open cut will allow blood to spill out, like water from a broken fire hydrant. Blood carries oxygen and nutrients to all organs, [...]

How come onions make you cry?

Kathy Wollard — Sat, 09 Jun 2012 23:53:33 +0000

How come onions make you cry? asks reader Jessica R.

Elaborate precautions and instructions. Special patented peeling devices. Goggles, with foam seals and anti-fog lenses. Chemical warfare protection, all to produce a slice of something you’ll happily eat on a sandwich.

An onion, uncut.

Onions are a vegetable that seems to resist being eaten. [...]

Why do icicles have pointy ends?

Kathy Wollard — Mon, 12 Mar 2012 06:00:32 +0000

Why do icicles have pointy ends? asks a reader.

Icicles hanging from the roof on a winter’s day look like glittering stalactites, suspended from the roofs of hidden caves. It wasn’t until 2005 that scientists figured out the mathematical formula = that described the shape of stalactites. In 2006, those same University of Arizona scientists [...]

How come foods like apples can get moldy, even in a cold refrigerator crisper drawer?

Kathy Wollard — Thu, 08 Mar 2012 01:29:52 +0000

How come foods like apples can get moldy, even in a cold refrigerator crisper drawer? asks reader Stephanie Waslin.

Ever start to bite into a red, ripe strawberry, only to discover a slimy white coating on the underside? As the fast food commercial goes, “You gotta eat.” Except in this case, it’s the mold that’s [...]

How come in cold weather your nose runs and your eyes tear?

Kathy Wollard — Mon, 27 Feb 2012 06:00:04 +0000

How come in cold weather your nose runs and your eyes tear? Also, how come when you put milk on puffed rice cereal, it makes a popping sound? asks Emily Abrams, a student at Long Island Lutheran Middle School, in Brookville,

NY. Winter is notorious for its dry air. And yet, when it comes to [...]

How come, if you put water and oil together, the water will rise and the oil will sink?

Kathy Wollard — Mon, 20 Feb 2012 06:00:09 +0000

How come, if you put water and oil together, the water will rise and the oil will sink? asks Walton Rea, a student in Brookville, NY.

Actually — although it seems unlikely — the opposite occurs. It’s oil that does the rising. Just check out any oil-and- vinegar salad dressing in your refrigerator. (Note: vinegar [...]

Why does your tongue stick to freezing-cold metal? Also, why is it easier to burn your tongue or mouth on pizza than on a hot drink?

Kathy Wollard — Mon, 13 Feb 2012 06:00:44 +0000

Why does your tongue stick to freezing-cold metal? Also, why is it easier to burn your tongue or mouth on pizza than on a hot drink? asks a reader.

In the movie “A Christmas Story,” it’s a triple-dog-dare that prompts Flick to taste a freezing-cold flagpole on a winter’s day in Indiana. When he can’t [...]

How come our blood is a blue-purple color inside our bodies, but red when it’s on the outside of us?

Kathy Wollard — Mon, 06 Feb 2012 06:00:35 +0000

How come our blood is a blue-purple color inside our bodies, but red when it’s on the outside of us? asks Tim Youngquist.

On a winter’s day, walking to school in a frigid wind, your nose turns Rudolph-red. Later, embarrassed by something you did in class, you feel a rosy blush spread across your face. [...]

How come ice is so slippery?

Kathy Wollard — Mon, 30 Jan 2012 06:00:59 +0000

How come ice is so slippery? asks Rebecca Anderson, a student in Brookville, NY.

If you’ve ever careened into the sink on your way across the kitchen in the morning, you know a patch of spilled water is slippery. On a dry floor, the friction between your shoes and the floor’s surface keeps you from [...]

Why does putting on a coat in cold weather make us warmer?

Kathy Wollard — Fri, 27 Jan 2012 02:53:41 +0000

Why does putting on a coat in cold weather make us warmer? asks a reader.

Go out lightly dressed on a frigid day, and thermal energy will quickly drain away from you into the cold December air. But unlike a run-down mechanical bunny, you don’t need new batteries. A warm coat pulled from the back [...]