Class Intro

Table of Contents

1. Expectations

Learn what to expect from science class and what will be expected of you.
On a separate sheet of lined paper, tell me about something you did in science class before that you enjoyed, or something you are hoping to do in science.
  1. What will we be studying?
  2. What will class be like?
  3. What will tests be like?
  4. What kind of behavior is expected?

1.1. Trebuchet

One of the things that cam out in discussing the do-now is that one thing that a lot of you like about science class is having the chance to build things. I showed you something that I built: a medieval siege weapon called a trebuchet.

In the the fourteenth century, among all the turmoil of plagues and wars, there was one revolution that went largely unnoticed, but which was to affect the world from that point on. Castles had become almost impregnable, with several concentric layers of walls and moats and intricate defense mechanisms that made taking a castle by force almost impossible. All that an attacking army could do was to surround the castle and hope to starve out those inside before the castle's allies could attack the besiegers or cut off their supply routes.

All of this changed with the introduction of the trebuchet. Catapults and other siege engines had been in use before, but the trebuchet was a step beyond them all. It was powerful enough to hurl a boulder weighing hundreds of pounds to hit a wall three football fields away. It had a deceptively lazy throwing motion that could be repeated indefinitely - unlike a catapult, it wasn't prone to unexpectedly tearing itself apart under the strain of twisted rope and bent beams, sending shards of wood flying out among its operators with explosive force.

The most fearsome characteristic of the trebuchet, however, was its accuracy. Once it was set up, it would hit the same piece of wall over and over again. With a team of men to operate it, it could fire a boulder every four minutes, around the clock. No matter how thick the wall, it could not stand up to such repeated pounding; when the castle defenders saw a trebuchet being built, they knew that if it were completed, there castle would fall.

Before the trebuchet, the most important people in war were the knights - people who had trained for years and years so that they could sit up on a horse wearing hundreds of pounds of armor and stab each other with lances or hit each other with swords. Castles existed for the sake of knights: they could hide in the castle, safe from their enemies, then ride out on a day trip to beat up someone nearby, then ride back into the castle before nightfall to eat and drink and party again. Now, all of a sudden, with the invention of the trebuchet, knights found themselves demoted to the role of guarding the people who were doing the real work of warfare.

The waging of the war, now, fell to an unlikely group of people: without great strength in their arms, nor great skill with the sword, wielding only pencils and papyrus, they would disappear into the woods to cut giant beams, melt down the lead roofs of nearby towns for a counterweight, and build the machines that would defeat walls that all the knights of Europe could fling themselves against in vain. These people were the engineers, and their weapon was mathematics.

Since then, those who wield mathematics have risen to more and more power. There is not much call in our society anymore for those who can wear metal armor and fight on horseback, but most jobs do require a solid understanding of math and science, and as the computer age takes hold, math and science will rapidly become the indispensable language of work. The goal of this class, then, is to teach you to understand the basics of math and science. You will graduate from this class knowing that if the situation ever gets that desperate, you would be able to build a trebuchet with your science skills and save the day.

Handout: Expectations and Grading Policy.

2. Thinking like a Scientist

Learn what it means to be a scientist.
How do you think a scientist baking a cake would act differently from an ordinary person baking a cake?
  1. "I am a scientist."
  2. Grading Policy
  3. Lab Room

2.1. Baking

I chose that question for the do-now, because my wife is a scientist (she is a biochemist), she loves to bake, and she definitely approaches baking with a scientific worldview.

When I bake anything, I end up with little bits of batter all over the counters, and a light dusting of flour on top from over-enthusiastic mixing. When my wife bakes something, the kitchen ends up completely spotless. She works in a lab with very dangerous chemicals, so if she spills something in lab she might have to evacuate the whole lab and call a haz-mat team in; thus, she has gotten very good at not spilling things.

My wife also bakes primarily to satisfy her scientific curiosity, rather than for any practical purpose. She'll have a new recipe she wants to try, or a way that she wants to modify an old recipe, and she'll try it out right then because she's so excited to see how it works out. This means that we often end up with three or four cakes around at a time, and we have to invite friends over to help eat it, or else I have to tell my brother, "Here - take half a cake, quick!"

2.2. Thinking like a scientist

I really enjoy teaching science in middle school, because you are all right at the age when you are discovering your own ability to think like a scientist. This is a natural part of your brain's development.

If I were to take a tall glass full of water, and a wider, empty glass, and pour the water from the tall glass into the other, it would be obvious to all of you that the amount of water did not change. The funny thing is that if you show the same thing to a four-year-old, they will be convinced that there is less water in the wide glass. They have not yet learned to think in terms of something staying the same as shape is changed. Psychologists have studied this and found that in all kids, around the age of seven, there is a time when their brain makes that connection, and starts thinking in that way, and all of a sudden they can watch you roll out clay into a snake, or pile up sand into a hill, or watch you pour water, and be able to tell you, "The amount is the same! It's the same stuff, just changed in shape!"

Something like this is happening to you right now. There are all kinds of switches in your mind that are being turned on for the first time. There are new ways of thinking being opened up to you that you have never had before. And all those things have to do with thinking scientifically. So I can almost guarantee that you will find science class exciting, because you will discover that you are able to understand things in a deeper way than you ever have before.

So, just remember that you don't have to learn to be a scientist: you already are a scientist. Your brain is growing in that direction right now, as surely as a plant grows up toward the sun. So every morning, when you get up and look yourself in the eye in the mirror, you can say to yourself with pride, "I am a scientist!"

2.3. Why is it fun to be a scientist?

What, you might be asking yourself, is the big deal about being a scientist? Why is that so cool? I gave you three example in class of why approaching the world with a scientific attitude makes life more fun.

Scientists are always thinking. As an example of this, I read you a story told by Richard Feynman in his book Surely you're Joking, Mr. Feynman! about how he got in trouble for trying to improve on the method of cutting beans, as a kid. It's fun to be always thinking, because it means that you will never be bored: even when Feynman is doing a boring task like cutting beans, his mind is going a mile a minute: "Now, what if I had some kind of knife... Could I use a bowl to catch the beans?... What angle will work best?"

If you've ever been bored in class, it probably means that you were sitting there like a lump of clay saying "Entertain me!" and waiting for the class to push your brain into motion. If you instead actively and imaginatively engage with what's going on, you'll find class a lot more interesting, and you'll find that even in a very basic class you can, in your own head, ratchet up your level of thinking about the class to the point where it's actually a challenge.

Scientists are not afraid of mistakes. This means that if you take a scientific attitude toward the world, you never need to be embarassed by something you did wrong; you can just think, "OK, I guess I need to work on that a bit more." When Feynman was still sitting there with his finger bleeding and throbbing, he was already thinking about how to improve his bean-cutting method to eliminate that problem.

I showed you a flute that I made in which it took three tries to get the position of the holes right. It's a somewhat difficult flute to play, as a result, since the correct holes are rotated off to the side, and it definitely doesn't look pretty, with all the bad holes plugged with duct tape, but I treasure it because it reminds me of the story that I had to try again and again before I got it right.

Scientists want things to be proven. This is something we will talk a lot about this year: what it means to be able to convince yourself that your answer is right. I told you this story as an example:

My parents have an old dishwasher that they've had for almost 32 years, the whole time they've been married. Because it's so old, in order for it to work well, you have to rinse all the food off the plates before you put them in the dishwasher; it just deals with the little bit of oil that is left. This leads to a problem, because there is no way to tell a clean dishwasher apart from a dirty one - the plates have no food on them either way.

So, my parents have a rule, to try to avoid putting dirty plates into a clean dishwasher: whoever unlocks and opens the dishwasher after it runs has to put away all the dishes inside. This led my siblings and I, as kids, to always try our best not to be the one opening the dishwasher when it was clean. If we couldn't find a fork, we'd search all over for one, or eat with our fingers even, rather than open the dishwasher and be required to put all the dishes away.

I was at my parents' house a few weeks ago, and I wanted a fork to eat some scrambled eggs with, and of course there were no forks in the drawer, and no spoons either. So, I had to go look in the dishwasher. But, it was unlocked, so I thought "Hooray! The dishwasher is still dirty! I don't have to put the dishes away!" and I just took one fork out, washed it with soap and water, and ate with it.

But by the time I was ready to put my fork back in the dishwasher, my science-mind had begun to raise some doubts. Maybe, I thought to myself, some sibling of mine had opened the dishwasher when it was clean, and then had nefariously snuck off without putting the dishes away! If I was going to put my dirty fork in the dishwasher, I had to be certain that it really was dirty. So first, I thought to myself, "If the dishwasher had run, the plates would be hot, and there might be some steam. There was no heat or steam when I opened it, so it must be dirty." But then, it occurred to me that if someone else had opened the dishwasher already, the heat and steam would have escaped; so, I was back where I started.

Next, I remembered that when the dishwasher has run, there is often a little puddle of water on top of the plastic cups, but not the glass ones. This is because the plastic cools down quickly, but the glass does not - something that you've surely noticed if you ever tried to empty the dishwasher just after it ran. Because the glasses are hot, the water evaporates off of them; because the plastic cups are cool, the water can collect there.

I looked back in the dishwasher again, and, sure enough, there were little puddles on the plastic cups, and not on the glasses. So, it turns out this is a sad story - I had to put the dishes away after all. But, you can see how I was thinking like a scientist, wanting to be absolutely certain.

2.4. Lab room

At this point in class, we lined up and went to the lab room. Since there's no space to line up in the classroom, and we don't want to be stomping, clapping, and smacking our lips in the hallway while other classes are going on, we go to science lab by just having me lead out the column next to the windows, then joining the next column to that as the last person goes by, and so on.

The first thing I need you to know about the lab room is that I will get really mad if you write on or otherwise deface the equipment. I come from this family that has a 32-year-old dishwasher; in my family culture, we try to buy really well-made things and then make them last a long time. So, I do the same thing with my lab supplies: I buy the best supplies I can get, or make them as sturdy as possible, and then I want those supplies to last for a good 20 years of students.

So, if you accidentally drop a test tube, I'm not going to be mad - accidents happen to all of us. I've broken more than my fair share of glassware. But if I see you writing your name on the microscopes, or poking holes in something, I just see red: I'll be so irate I'll have to step out of the school and scream a couple of times before I come back in and give you your demerits. So, that's your warning: I'm just weird that way, so look out.

The last thing I briefly talked about is lab safety. When you're in lab, you should be acting in slightly-more-cautious-than-normal mode, like you do when you are walking through an unfamiliar neighborhood at night. Don't take silly risks, and don't take for granted that you know what something is. If you are really thirsty and you see a beaker of clear liquid on the lab bench, taking a drink of it might not be a really good idea.

I drove home this last point with a fun demo: an exploding outhouse mousetrap piggy-bank. It sure is surprising when you drop a coin in and the whole thing explodes!