What did you learn?

While I was at the National Academies Press website downloading stuff for a previous post, I ran across a title in their catalogue that caught my eye:

Surrounded by Science

Since it was free, and it was about everyday science everywhere and teaching people about science, I downloaded it. Because, you know, Science!

I was nodding right from the first two paragraphs of the preface. Do you remember going to some museum, or aquarium, or other educational and fun location, get interested, have a fun time, then at the end of it get asked by your teachers or parents, "what did you learn?"

And then drawing a blank.

The funny thing is, the first thing I thought of when I read that was actually back in university, when halfway through any given class the professor would announce the date of the midterm: my first thought was usually to wonder what he could possibly test us on, we hadn't hardly learned anything.

I don't know if the book answers the question of how to help kids answer the question "what did you learn?" (I haven't finished reading it yet) but it certainly tries to answer the question of how to help people learn and absorb and integrate science more effectively.

Personally I think instead of asking what they learned, you should ask your kid what were some of the cool things they saw. They'll probably surprise you with the amount of stuff they learned. (I saw a deer with fangs at a museum once. That was seriously weird.)

Magnetic soap

This video demonstrates a nifty advance in surfactant science: unfortunately I can't include it here, so you have to click on supporting information then the .mpg video file link to see it.

What is shown on the right, sticking to the metallic disk being lowered into the liquid, is magnetic soap. (On the left is normal, non-magnetic soap.) The little yellow blob that lifted with the magnet-on-a-stick through the clear liquid and then fell when the magnet was lifted right out of the liquid, is the soap itself.

Three different non-magnetic surfactants were made magnetic by reacting them with ferric chloride, a common industrial chemical.

A solution of ferric chloride by itself also reacts very slightly to magnets, but it finds most of its use as a coagulant, not as a soap.

Violent separation

In keeping with my original plan for this blog, I am now going to teach myself something new.

Here is something I have known about and occasionally seen since I was a kid, and know the name of, but hadn't seen it in operation and didn't actually know how it worked until I decided to write this post and figure it out:

It works exactly the same way as this thing, which I saw for the first time as an adult:

Recycling water

It may be something we don't like to think about, but one of the things the astronauts have to do while in orbit will be coming more and more to Earth. Fresh water is limited, and getting more so with time. Water conservation helps, but it may not be enough in the future.

Whether they are dependent on well water or surface water, many cities have to worry about having enough water to last through the dry season as the water levels drop. Water restrictions are common in some areas; where I grew up, part of the summer routine was that you couldn't water your lawn whenever you wanted, but only on certain days. Sometimes there was an outright ban on watering lawns if the river level was too low.

At the same time, the volume of water leaving a city's wastewater treatment plant is a substantial part of what the city brought in to start with, and grows with population more than the season.

As wastewater treatment technology improves, the sewage plant's discharge gets cleaner and cleaner, so why not use it as feed for our clean water treatment system?

Airplane-induced snow

An airplane made that hole.

Not by just flying through it and swirling the visible cloud out of the way, that makes a different pattern which doesn't last nearly as long.

It turns out that in certain conditions, airplanes can actually induce rain or snow in a localized region of a cloud, and the precipitation is what clears the hole - the water droplets that make up the cloud fall because of the airplane.

Happy new year

Well, I haven't been at this for a full year, but it's been an interesting seven months so far. I've definitely spent a lot more time keeping up with the science news by trying to post something every week. I'm also glad I didn't set out to try to post more than one a week!

I think I'll stick with the Monday post schedule, even if sometimes I have to post something light. I'm also going to try to do more chemistry type stuff; it surprised me how much time I spent outside of chemical engineering and related fields. I also want to do more posts calculating random things, because the ones I've done so far were a lot of fun for me.

Let's see how the next year goes...

Platinum and power

One of the classes I took in university was on electrochemistry and fuel cells. It was very interesting, but was also a reality check on the hype of hydrogen fuel cells vs. the reality. One item in particular that stood out for me was that the catalyst required for efficient, low temperature hydrogen fuel cell operation was platinum. While platinum isn't the most expensive metal out there, gold having passed it in price not too long ago, it's way up there. As I recall, the raw platinum required to make a fuel cell cost a significant fraction of the cost of a normal car, and that was before they processed it into a useful catalyst. Since then, they've improved the structure here and there and reduced the amount of platinum required bit by bit, but it's still a lot.

Not long ago, however, some researchers in Finland figured out a way to reduce the amount of platinum by more than half.

Rusty mittens

Just for fun, and because it's winter, I thought I'd look at mitten heaters, specifically the non-reusable type that comes with a warning not to take the plastic off until you're ready to use them. You've probably seen them sold with outdoor recreation stuff, such as camping gear. They're little cloth pockets with a powder inside, and you can stuff them inside your shoes or mittens to help keep warm.

There are a few ingredients in that powder, but only one produces heat. I think the others moderate the speed of the reaction so it lasts about a half hour, instead of getting a lot hotter and only lasting a few minutes.

The source of heat is a multi-step, electrochemical reaction: rust.

Fake snowflakes

You know how they say no two snowflakes are alike?

It turns out that they're so sensitive to the conditions they form in, and are also fragile in a turbulent area, that the odds of two snowflakes growing in precisely the same way and having the exact same collisions breaking pieces off as they go are pretty small.

There are, however, a few main shapes of snowflakes that all snowflakes follow.

Science fiction fans, rejoice!

All I can really say about this is, WOW.

NASA's Kepler team has found loads of planet candidates to date (about 2300) by measuring variations in brightness in the star as the planet orbits. They've confirmed a bunch of them as well, so we know there are other planets out there. And just in case you think 2300 is a low number considering how many stars are in the sky, keep in mind that the Kepler telescope has been staring at a patch of sky about the size of your outstretched hand the entire time. I don't know about you, but I can't even see 2300 stars in that kind of an area, and the Kepler telescope has found that many planet candidates.

Now they've found one in its star's habitable zone - where liquid water can exist.

If you take a look at their news story, they show our solar system with the habitable zone defined - Venus is too close to the sun to be habitable, but Earth and Mars are both in the right area. This is why they've been sending robots to Mars to look for evidence of past water. Past water, because Mars' atmosphere is much too thin to retain enough heat to have present water, but it does have present ice in the form of its polar ice caps (as well as solid CO₂, dry ice).

It remains to be seen whether this planet has an atmosphere which will hold in enough heat to maintain liquid water, but at least its orbit is in the right place for this even to be an option. Composition of some planets' atmospheres (mostly the early Jupiter-sized ones so far) has been studied using infrared absorption spectra, which is a whole level of nifty that I would need to study for a while to understand.