Sugar cubes are interesting things, and not just because they make your coffee sweeter. Take two cubes and rub them together over a clean, dark, flat surface, then go grab a magnifying glass. What you should see is hundreds of tiny sugar cube-like grains. That's pretty cool in its own right. What's really cool is that sugar, in its solid form, is a crystal, which means that no matter how small you make it, even down to a few molecules, it will still be try to be a cube. (Yes, I know that a sugar cube is actually made up of "grains" of sugar compressed to form a cube, but the illusion is pretty cool nonetheless.)
So, if I took a hammer and smashed one of those sugar grains, and I had a powerful magnifier, what I should see is even smaller cubes. Smash them some more and I'd get even smaller cubes. That's cool.
Mercury is also pretty cool. It's a metal, and when we think of metals we tend to think of them being hard, solid and strong, but mercury is none of those, at least not at room temperature. See, mercury is a liquid at room temperature. You'd have to chill mercury to -38 degrees (F) to get it to shape up as a solid. And would you believe it? When it's a solid it is also a crystal!
The difference between sugar and mercury, besides the fact that one will rot you teeth while the other will cause your hair, nails and teeth to fall out, is that if you keep smashing sugar until you got a single molecule of it, then smashed it again you'd no longer have sugar, just a bunch of carbon, oxygen, and hydrogen atoms. That's because sugar is a compound, a substance made of two or more elements.
Mercury, on the other hand, will still be mercury, right down the the last atom. That's because mercury is an element, one of the 118 known substances that, alone or in combination with other elements, make up everything in the known universe.
So, why am I showing off my basic knowledge of physical science? Because in most places in these United States, children are heading back to school, and grade schoolers will likely be exposed to such ideas for the first time.
Think about it. Kids will learn why wood is wood, why an empty glass isn't empty, and why the light comes on when they flip a switch. Powerful knowledge, and often a lot to wrap even young and pliable brains around. Sometimes it helps to visualize a concept, and if you have an iPad, then you can have some very handy and powerful learning aids at hand, and for free!
If you've ever watched any public TV, you'll recognize Nova, the award winning science show that exposes viewers to many facets of the physical world. The same folks, along with the popular New York Times tech columnists, David Pogue, are behind a free iOS app called, simply enough, NOVA Elements.
This is one of those apps that's hard for me to believe is free because it's done so well. There are videos, all featuring Mr. Pogue, of course, an interactive periodic table, and a teaching aid/game where you can create the compounds that make up the stuff all around us.
Are you wearing a red t-shirt? You can create the atoms, then molecules that make up cotton, nylon, and red dye, each of the substances that make your red shirt a red shirt and not a watermelon.
The interface is simple and a joy to use. Tap one of three sections, Explore, Play, Watch, and you get to do just that. All this elemental goodness and not one ad or in-app purchase in sight.
If you've got kids in school or just want to brush up on your knowledge of physical science then NOVA Elements is what you want.
In addition to messing with matter at the atomic level with Nova Elements, you may want to view more complex substances like DNA, rubber, or aspirin. For that you need Molecules, another freebie iOS app that puts everyday substances in a whole new light.
Unlike NOVA Elements, you can't construct molecules from atoms, but you can download and view just about every imaginable substance, even if you're not entirely sure what the stuff is. For instance, if you want to look at a sugar molecule, Molecules will search the PubChem database, returning hits for sucrose and several other derivatives. Pretty cool.
You are presented with a 3D model of the molecule which you can view from angle, and there's a color code so you can easily figure out which atom is where.
There's not much more to Molecules, but in this case, simple is best.
You've played with elements, marveled at molecules, now it's time to take it to the next level. Atoms form molecules, and molecules form everything else, including you, me, the air we breathe, the trees in your yard, everything. That's a lot of stuff. It would be nice to study it all to see it all works, but that would take forever, literally. So why not make a casual study of the things close at hand, like the trees in your yard?
Study trees? Boooorrrriiinnngg!
Maybe, but not so much if you have Leafsnap. Think of Leafsnap as a field study aid. Found an interesting looking leaf? Put it on a white background and take shot with your iPhone and Leafsnap with query its database to find all the likely tree candidates.
Use location services to locate interesting trees in your immediate area. When you find a likely match you can catalog it and continue your study. If you're not sure you have a match, pick a candidate and other features of the tree, such as fruit, bark and leaf clusters are shown to help you identify your subject. Not so boring after all, right?
At the front page Leafsnap gives a photo show of the features of the trees it has in its database. In all, it's a fun app to have handy when walking through the woods this fall.
There are no ad or in-app purchases to deal with, just a nice little app that's a breeze to use. Leafsnap. Grab it and start your leaf catalog.
That's a wrap for this week. More great freebie right here next week.