First, we reviewed what we went over last week about what science is and where it started and why it started there.
Then I introduced our topic for this week: Thales (thay-leez). We discussed Thales as the first scientific thinker. We discussed that the Ancient Greeks before Thales would explain earthquakes as caused by gods. Thales thought the Earth might be over top of water and the motion of the water would cause earthquakes. Another of Thales thoughts that was that all things were water (to be picky it's hard to tell if he thought all things started with water if all things were made with water).
Both of those ideas are wrong, but it the ideas were important for a number of reasons. Thales was working with what he noticed around him. He was trying to explain what he observed. But he wasn't just explaining the particular instances he observed, he was generalizing his ideas to include all such events (every earthquake, not just the one in Greece last year). The ideas are also important because they were natural explanations--not relying on gods.
Here's what I wrote on the board:
- Thales ~600 BC
- First Natural Explanations
I brought out my loadstone sample (my $3 specimen that isn't actually magnetic) and the kids could observe that it had rust on it. We then switched to real magnets and filled out a chart like the following:
Attracted Not Attracted
We tested a number of materials like steel, brass, paper, plastic, wood, cork, paper clips (or we would have if I had found them), and aluminum. I let the kids keep their magnets so they could do more testing at home.
Afterward, we talked about how Thales noticed that rubbing amber allowed it to attract little bits of stuff. We tried rubbing plastic rulers with our hair, but that didn't work as well as the balloons. The kids ripped up paper into little squares and then were able to use the balloons to pick it up after rubbing the balloons on their hair. They also got the balloons to stick to the walls (who hasn't done that?), attract the cloth of the tablecloth, stick their skin, and pick up bits of yucky stuff from the floor near the baseboard (where your vacuum will miss). I pointed out that magnets attract only specific things but that the balloons seemed to attract everything.
At the end, I decided to review 45 degree right angle triangles (I may decide to talk about how Thales may have measured buildings' heights by measuring its shadow at the time of day when the shadow and the object make a 45 degree right triangle). I also reviewed circles, ellipses (how a circle at an angle would be foreshortened), cylinders (if the Earth only curved in one direction), spheres, hemispheres (hmm--not sure I really had a reason to introduce this--perhaps I'll remember later), and squares and cubes (if a square were stretched in height) to prepare for area and volume discussions.
In order to get the kids to understand the importance of angle (let's not forget that I'm spanning 1st grade to 4th grade in this class), I held up a square and asked them what the shape was. After they all said square, I asked how they knew. The answer was, of course, four equal sides. I drew a rhombus on the board (a parallelogram with four equal sides, a diamond) and asked them if that was a square. They all answered no and I asked why not? Why was one shape with four equal sides a square and the other wasn't? One of the kids (who's advanced in math) knew that squares have perpendicular sides that make a right angle. I also showed three different size 45 degree right triangles and pointed out that as one side got longer, the other side got longer by the same amount and because a 45 degree right triangle is half a square, the kids know the two straight sides have to be equal in length.
At this point, I'm not going into the explanations, just doing the same type of exploration that Thales may have done. I didn't bother giving the kids the other explanations the Greeks came up with to explain the behavior. I may choose to go into that when I switch from a purely historical presentation to a presentation for each discipline (after the ancients). Most of what I tell the kids is generalized and I am not trying to present the entire picture--just enough to get us going. I know some of the details are being questioned at this point (like the solar eclipse prediction), but the kids can worry about that if they ever become historians.
Our next class (or two) will discuss some of the cosmologies of the Ancient Greeks. I'll be presenting evidence that the world curves and the ideas of the heavens moving around us. I'll also quickly present Empedocles idea of the four elements and their forces. Then I need to present Aristotle's reliance on observation over another's conclusion (if I can find it). Once those thing are out of the way, I'm all about Archimedes.