On with the show.
In the June 20 list of science teaching tidbits, I talked about what senses you could ascribe to plants, and somewhat dismissed the concept that plants could “see.” Well, I didn’t put enough thought into it, and failed to consider the range of what “sight” means. Sight in flatworms can be something as simple as detecting the presence of light and moving towards it.
Daniel Chamovitz, of Tel Aviv University, in a Scientific American 60 second science blog post, points out that plants “see colors, they see directions, they see intensities.”
And beyond that, they respond to direction, through a process called phototropism, where the plant grows towards light.
The great thing about science is that you can be excited by being wrong.
Also from Scientific American is one of the most ignored members of our phylum, chordata, the sea squirt. We rarely do more than mention tunicates and lancelets in passing and move on to the better known and more popular vertebrates, which is really a shame. These oddities of chordata are very useful in spicing up a lecture on diversity. What is more different from a mammal than an organism that only swims as a larva, then settles down, becomes sessile, grows a shell and lives as a filter feeder for the rest of its life, resembling a mussel more than anything else?
Finally, an incredibly old impact crater was recently found in Greenland, as in around 3 billion years old. It isn’t the biggest, but its the oldest. There are impact craters all over the world, some in our own back yards, many of which are not much to look at from the ground, but can stick out on a satellite image. For example, put 38.305000,-86.500000 in as your coordinates on google maps. As you zoom out, you will begin to see a broken ring. This is thought to be the site of a meteor strike in the ancient past of Indiana (I don’t have my roadside geology guide handy, or I’d give more details), and the surrounding land bears the shocked quartz, deformed bedrock and sedentary fill, and even the gravity density of a meteor site. Completely invisible from the ground.
The Kentland, Indiana crater is better known, but all kinds of things are just under our metaphorical noses. You don’t have to go to Arizona to stand where the sky fell. This makes the rare meteor crater site on the other side of the country or world a bit more close to home, and therefore, interesting.
If you want to go a little further in a physics class, here is a nice little experiment that you can do with fairly little setup or expense.