A brave COSI educator reached out to me recently, requiring my assistance to settle a workplace debate. Brave because the educator had a question for me that they felt was a little on the silly - or perhaps worse, obvious - side, and didn't want to display their apparent ignorance to the world. That natural reluctance, while perfectly understandable, is a major impediment to science education, and developing strategies to overcome that will be the subject of another memo.

But for today we have the central question: what direction do rivers flow? North-to-south? South-to-north? Downhill? Something else?

Well, let's look at the major rivers of the world:

Amazon: west to east
Nile: south to north
Yangtze: west to east
Mississippi: north to south

Our own Scioto river flows from north to south, where it joins the westward-flowing Ohio river, and eventually to the south-heading Mississippi.

So rivers definitely don't follow a particular direction around the globe, but what sets their course? The answer is "downhill", but not in the way you might expect. While the Amazon's headwaters are in the mighty Andes mountains, the Mississippi is born in modestly hilly Minnesota.

To see why a river flows in a particular direction, you must ask yourself: "If I were a drop of water falling from the sky, where would I go?" If you fell on the eastern side of the Rocky Mountains, for example, you might find your way to a small stream that connects to the Missouri River, heading eastwards until you join the Mississippi. Even though the Mississippi has humble origins, it's fed by rainwater in the distant mountains.

The collection of all sources of a particular river is called its watershed, and detailed mapping and sophisticated algorithms can reveal what "downhill" really means to a river.

I'm no stranger to farms. I grew up surrounded by them, my undergrad university in California had a big agriculture program (and a dairy with some delicious cheeses, but I digress), and my graduate school in Illinois was notable for an experimental corn field right in the middle of campus.

But when a correspondent for Farm World magazine reached out to me for an interview, I was surprised. One, that there is a Farm World magazine and it's apparently a big deal; and two, that they wanted to talk to an astrophysicist. About sunspots.

Over the course of the interview I learned a lot, and what struck me the most was how sophisticated the industry is. GPS, drones, specialized weather simulations, complex market forecasting, cutting-edge research in biotechnology, the works. I suppose if 2% of the US is feeding the remaining 98% (and then some), they've got to be pretty smart about it.

And farmers - as an industry - think about sunspots. There's a notion that sunspot activity is connected to weather. While the sun's brightness does change, and does so in a measurable way, it doesn't substantially affect our weather. But increased sunspot activity is tied to higher rates of solar storms, which do seriously impact both weather and GPS satellites. And that's definitely something for a farmer to worry about.

Brian Krosnick, one of COSI's fantastic outreach education specialists, reached out to me with a mythbuster-style query: a common trope in cartoons and movies is for someone to trigger a deadly avalanche by shouting, or even worse, by just whispering. Just how dangerous is a little yodel-le-he-ho on the mountain slope?

Fortunately for hikers and skiers everywhere, a little yodeling can go a long way with no risk of triggering an avalanche. Snowpacks on mountains are indeed precarious situations, with the tremendous weight of the snow itself balanced only by friction. And once set in motion an entire slab of snow can fracture off and slide down a mountain en masse to wreak havoc.

But sound is actually very weak. Think about it: a lungful of air and a tiny voicebox can fill an entire auditorium with sound. If you drop something on the ground, usually less than 5% of the energy is converted into sound. And so on.

A nice loud yell provides less than one hundredth the energy needed to initiate an avalanche, but that doesn't mean mountain-goers are out of danger. Simply walking or skiing on an insecure snowbank can supply the pressure needed to overwhelm stability and trigger an avalanche. Indeed, somewhere north of 90% of fatal avalanches are caused by the very people who end up dying in them.