Wednesday, September 23, 2009

Atoms in a historical context

We finally leaped head first into Science. Being naturally disinclined to follow instructions exactly, I am using the Apologia text, Exploring Creation with General Science as a guide. Their approach to science is historical which is right down our ally! We'll deviate somewhat later because some of the history it presents I think is contradicted elsewhere so we'll be learning about that too.

The text opens with a brief introduction of Imhotep (eem' oh tep) from ancient Egypt around 2650 B.C. adding the note "most historians agree that the heart of Egyptian medicine was trial and error" and that a very important reason the Egyptians were so advanced in the art of medicine was because they had papyrus. They wrote everything down.

For example, they learned that they could get open wounds to heal quickly and cleanly by applying moldy bread on it. Sounds gross, right? Of course, most of us know that moldy bread produces penicillin, and that's why it worked. Back in ancient Egypt, they just wanted to know what worked, not particularly why.

Next, we learned that Greek scientists were the earliest "true" scientists that we know about. They systematically collected facts and observations and then used them to explain the natural world.

The Greeks we learned about were Thales, Anaximander (an axe' uh man der), and Anaximenes (an axe' uh me nees), followed by Leucippus (lew sip' us). He is called the "father of atomic theory". Much more is known about his student Democritus (duh mah' crit us)who continued the study of atoms.

I really liked the visual illustration Democritus used to explain atoms. He used the analogy of sand to explain atoms, likening the atoms to grains of sand. Quoting from the book, it says, "Think about walking towards a sandy beach. When you are a long way from the beach, the sand looks like a smooth, yellow blanket. As you get closer to the beach, you might notice that there are bumps and valleys in the sand, but the sand still looks solid. When you reach the beach and actually kneel down and examine the sand, you find that it is not solid at all. Instead, it is composed of tiny particles called 'grains'."

The experiment was simple enough. We put canola oil, water, and corn syrup in a glass and saw what happened. Then we dropped in a cork, rock, ice cube, and a grape and observed what happened. Such as it is, here's the picture from my point and shoot camera:

It's hard to make out the picture, especially through the fish, but the corn syrup was on the bottom, water in the middle, oil on top. If you look closely, you can see different textures in the liquid. The cork (brown) floated on the oil, ice (look at the nose of the largest fish) on the water, grape (see the purple blob?) on the corn syrup, and rock on the bottom.

Afterward, we discussed how the experiment illustrated the theory of atoms. Briefly, we learned that the amount each object sank has to do with the density of the atoms in each item.

Tomorrow we will be discussing a bit more about Democritus and atomic motion with another experiment. It will also be much shorter lesson since we covered twice as much material as normal today.

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