Why you need to wear safety glasses

In case anybody didn't know why you should wear your safety glasses - and any other personal protective equipment.

If you still need to be convinced, check out the below video's progression from 1:00 - 3:30.

Extinguishing candles with sulfur hexafluoride

Extinguishing candles with sulfur hexafluoride. Or witch craft?

It's pretty straight forward.

Combustion - like the fire on the tiny candles - needs oxygen. Oxygen is slightly heavier than air (because air is mostly nitrogen gas, and oxygen is heavier than nitrogen), but sulfur hexafluoride is way heavier than oxygen or nitrogen or air.

So, the sulfur hexafluoride gas displaces the air, leaving no oxygen for the combustion reaction to burn.

It would be just like filling the large box with water, but you just can't see the sulfur hexafluoride.

Of course, there are problems with freely dumping sulfur hexafluoride out.

XKCD - disaster movie

Source - link

See, it's funny because scientists aren't the big, buff heroes often portrayed in disaster movies as being the people on the front lines leaping into the burning building, driving their trucks at the edge of the tornadoes, cruising around the island saving people from raptors, leaping lava rivers to save their damsel in distress.

Instead, scientists would be more likely to be looking to update their data about the world as the disaster happens. In fact, as explainxkcd explains (natch)...

The situation described (scrambling to update geographical datasets in the advent of natural disaster) is actually a common occurrence these days. The Humanitarian OpenStreetMap Team's Disaster Response unit does almost exactly this: When there is a natural disaster in a location that lacks high quality GIS data (common in much of the developing world), a team of volunteers across the world mobilises to update and improve OpenStreetMap. They use the latest available satellite imagery, usually donated free for the purpose. Disaster response teams then use the GIS data in OpenStreetMap to create maps and plan their response.

Inside the 23-Dimensional World of Your Car's Paint Job

We're continuing this week with a little more on the art theme. It's a very different kind of art from last week's memory metal flower, but there are still pedals involved. (groan)

Wired magazine has a brilliant article detailing the incredible process of color matching the paint on a repaired part of a car to the paint on the rest of the car. At first blush, the process seems awfully simple - pick up a can of the paint used to paint the car originally. Things are a little more complicated than that, however, as no repair shop is going to stock 50,000-60,000 different paints (the number of car colors on the road according to the article), no car in need of repair looks exactly like it did when it first rolled off the production line. and because the original paint job on most cars involves twenty three different dimensions to the color - sparkles, coarseness, red, blue, green, angle, diffuse coarseness, and so on.

The knowledge and skills involved in color matching are absolutely mind-boggling. There's an art to it all.

Aluminum recycling - How it works by Norsk Hydro

We have to recycle more.

There are many countries that are far, far better at recycling than is the US, but we (the US) have to get better.

I hadn't thought about the challenge of not just sorting the majority metals (steel from aluminum from copper from etc) but rather sorting the various similar metal alloys out from each other. The use of x-ray spectroscopy to do that is an application that I would never have considered, and the puff of air used to fire away the unacceptable aluminum alloy chips is amazingly fast.

It's amazing to me how technologically advanced the recycling industry is becoming.

Spinning Sphere of Molten Sodium

I know they're not doing this experiment - "12.5 tons of hot, liquid metal designed to spin at up to four revolutions per second" - because of any chemistry questions. Rather they're trying to explore the creation of the Earth's magnetic field.

But because they're using molten sodium, there are some fascinating chemical reactions that they need to avoid.

So they don't have a normal, water-based sprinkler system to avoid 'modestly catastrophic" because water on sodium, to quote Mr Mackey, 'it's bad, mkay'.

What is the NEW Silver Play Button REALLY made of?!

The video description doesn't remotely need that ?! at the end.

That being said, the process that the youtubers here go through to find out what specific elements are in the 'silver' play button is fascinating. The (?) Energy Dispersive X-ray Spectrometer is something that's new to me.

I'm particularly fascinated by the results at 5:39 showing the elemental makeup at various depths of the 'button.'

Yeah, all that's interesting, but what's the 'gold' play button award made of?