Flash photography used to be pretty wild

I remember having flash cubes in cameras when I was growing up, but I had no idea how literally explosive they really were.

There's a lot of build up and explanation, but the money shot really shows up around 20:30 and onward. It's then that they get the right resolution and exposure time to see what's really happening within the flash bulbs when they ignite.

Our phones are miraculous, but their flash isn't nearly as cool as a flash bulb ever was - much less the original limelight.

Water in Boiling Oil

Do NOT ever pour water on an oil or grease fire!

Ever!

NEVER EVER!

See - as the above video shows - if the oil is hot enough to burn, it's probably hot enough to boil the water you're splashing on it. If the water is hot enough to boil, then its volume will increase about 1600 times meaning that even a tiny drop of water will expand massively and push the oil above it out of the way.

If enough water drops do that, the oil splashes out of the put and will often turn into tiny liquid droplets in the air. That's called aerosolizing (like how liquid droplets come out of an aerosol can).

Those tiny oil droplets then can ALL catch fire at once, turning a tiny fire into a conflagration. (That's a big fire, donchaknow).

Let's let the Slo Mo Guys (and a few other folks) show us that happening.

Oxy-Acetylene Explosions at 330 000 fps | Fastest High Speed Camera on Youtube!

"I think this is bad idea," is my favorite quote from, I think, Lauri.

This video certainly isn't as bad an idea as heating a jackhammer up past its BCC -> FCC phase change. In fact, I think this video's a pretty great idea.

The video is a super slow motion look at the combustion of acetylene gas, producing a gorgeous, bright blue flame that I can't even see in real time.

Slow Motion Chemical Reactions

The University of Nottingham chemistry department has a YouTube channel called PeriodicVideos. On the channel they have videos about every element on the periodic table and quite a few about other chemistry topics as well.

One series they have is slow motion photography of chemical reactions.

I've put my favorite up high, but the others are after the jump.

HOLDING AN EXPLOSION at 20,000 fps - Smarter Every Day 156

That's brilliant.

The explosion there is wonderful and marvelous to watch. Gorgeous stuff, there.

Seriously, the explanation of the combustion and the slow-motion imagery is spectacular.

In the daytime, it's a little less thrilling.

Fire tornado in slow motion 4K - The Slow Mo Guys

We're not yet to chemical reactions in the course of honors chemistry (sadly, because that's the best chapter, honestly), but this is just too cool to hold off on.

I've done a much, much smaller version of this as an in-class demo to show the effects of increased oxygen on combustion...(not my video, by the way, but about the same set-up and scale)...