There's a saying in physics that just because something is simple, it doesn't mean it's easy. For example, "How does gravity work?" is a simple question, but even the likes of Newton and Einstein couldn't fully crack it.

Another deceptive question was sent to me the other day: when water is boiling, what's exactly coming out of the bubbles on the surface? I mean

Let's start with convection. When you heat a fluid on one side but keep it cool on the other, it will naturally start to mix with itself. That's because random blobs of fluid at the bottom will heat up just a little bit more than average. Heating up, they expand and become buoyant, rising to the surface. Once there they cool off and slink back down.

We see this same process all over nature. Pot of boiling water? Convection cells. Surface of the sun? Convection cells. Weather on the Earth? Convection cells. You get the idea.

Given enough energy, the water molecules start to get a little frisky, going from liquid to gas. This doesn't happen at the same time all across the pot of water. Again, randomly little blobs here and there will go gassy, expanding and rising to the surface when they do. But once there instead of sliding back down, the gas is free to escape, sending little packets of water out into the world in the form of water vapor.

So that's what's in a bubble of boiling water: water!

Recently you may have noticed a couple things: 1) COSI is getting a whole bunch of dinosaurs, and 2) I'm kind of excited by it.

Growing up I read - or more accurately, consumed - two kinds of books: books about space and books about dinosaurs. There was also an 80's cartoon series that featured dinosaurs from space, which while pretty awesome didn't offer much educational value.

So you can imagine my delight when I learned that a rock from space was responsible for killing almost all the dinosaurs about 65 million years ago. Don't get me wrong - I felt bad for the dinosaurs, but I was happy to learn that my two passions were strangely connected.

In fact it was a physicist and a geologist that first identified this cataclysm. Buried within strata all across the globe is a thin line of dark earth with an usually large concentration of iridium. Iridium is pretty heavy and pretty rare, since most of it sunk to the Earth's core billions of years ago before the planet chilled out from its molten state. But it's still found in abundance in any remnant from the days of the early solar system. Say, asteroids.

That dark line is about 65 million years old, and there are plenty of dinosaurs below it and not so many above it. Ergo: extinction event.

And the size of that dino-killer rock from space? A mere six miles across.

I recently had the pleasure of meeting team member Hannah Speranza (née Brooke) on her very last day at COSI, as she prepared to jet off to the city of Trieste, Italy with her husband.

It's a small world: I spent about two years in that very same Italian town. It's a lovely spot, nestled a couple hours away from Venice on the Adriatic coast just a short drive from the border of Slovenia. On a clear day you can see the Alps in the distance, and the city itself boasts a deep natural harbor surrounded by dramatic limestone karsts.

Trieste's architecture mirrors its eclectic heritage: an ancient Roman amphitheater sits in the town center next to a typical Italian piazza bordered by Austrian-style buildings. Coffee, pizza, schnitzel, and gelato shops string almost every street.

You wouldn't expect a relatively-unknown city like that to be a major international hub for physics, but the world is full of surprises. To start there's the International Centre for Theoretical Physics, founded by Nobel Laureate Abdus Salam, located behind a nineteenth-century castle. I worked at the Astronomical Observatory, which was split between two buildings: a hilltop site commissioned by Empress Maria Theresa in 1753 and a villa formerly owned by the Bazzoni family. There's also the University of Trieste, and a post-graduate school called SISSA located up the hill in a former tuberculosis clinic.

Fun place, filled with great science and - perhaps more importantly - great food.

This post is definitely not brought to you by the Trieste Tourism Bureau, but it might as well be.