Email+recaps

=Email recaps from Jim and Maria=

toc "Yes, we do assign computer games as homework"

Week eight, November 3rd, 2009
Jim: Today we worked a bit more on Newton’s Second Law. Newton’s Second Law is one of the toughest of the laws to understand but it is very powerful. In its mathematical form, it is so simple, it’s elegant. Mathematically it is F=ma or Force = Mass x Acceleration. An easy way to remember that is to think of your mother trying to get you out of bed in the morning. Force equals MA! In English, Newton’s Second Law can be stated a few different ways:The more mass something has and/or the faster it’s accelerating, the more force it will put on whatever it hits. F=ma For example, a car colliding at 30 mph will hit a lot harder then a fly colliding at 30 mph.The more mass something has, the more force that’s needed to get it to accelerate. For example, it is a lot harder to get a train to accelerate than it is to get a ping pong ball to accelerate. Now here’s an interesting definition. The definition of mass can be stated as m=F/a. In other words mass is how much force it takes to accelerate something. This is a major difference between mass and weight. Something with great weight on Earth may be weightless in space (since there’s no gravity) but it will still be just as difficult to get it to accelerate. We played with catapults today to get the point across. First we changed the mass of the projectile to show that the heavier the mass is, the less acceleration is given to the mass by the force. The heavier the ball, the less far it went. Then we changed the force by changing the rubber band. The greater the force, the more the ball accelerated. The greater the force of the rubber band, the farther the ball went.

Maria:

In class, we talked about "jello in space" mental model, with two forces acting on a spaceship: its jet engine, and the resistance of jello. You made the two forces variable. - Make the resistance increase until it is so great, the ship decelerates to a stop - Replace jello with "space wind" blowing in the opposite direction from the force of the engine. What are the possibilities here for different values of the engine's force and the wind's force? Katherine's model has something like that in place.

Earthlink decided to block my emails, which I am sorting out, but some of you did not get your previous homework and had to get it from others in the group - good thinking. I always send it on Tuesdays, and put it on our Wiki page, so if you don't get anything by Tuesday evening, head here: http://physicsmathmodeling.wikispaces.com/Email+recaps

We are actively planning the next 10 weeks. Jim wants to get deeper into forces and energies, and I want to work on game design in earnest: game mechanics, software development best practices, and a more powerful programming language (Python, probably with visual libraries). I'd like us to develop a bigger game with multiple levels, together, with individual group members or teams working on levels. I am very happy with the conceptual strength, communication and creativity of the group. I am confident we can work on big and interesting projects together.

Week seven, October 26th, 2009
Jim: Newton’s Second Law is one of the toughest of Newton’s laws to understand but it is very powerful and, in it’s mathematical form, it is so simple, it’s elegant. Mathematically it is **F=MA or Force = Mass X Acceleration.** An easy way to remember that is to think of your mother trying to get you out of bed in the morning. Force equals Ma! In English, Newton’s Second can be stated a few different ways:**The heavier something is and the faster it’s accelerating, the more force it will put on whatever it hits. F=MA** For example, a car colliding at 30 mph will hit a lot harder then a fly colliding at 30 mph.**The more mass something has, the more force that’s needed to get it to accelerate. A=F/M** This, by the way, is a mathematical definition for acceleration. For example, it is a lot harder to get a train to accelerate than it is to get a ping pong ball to accelerate. Now here’s an interesting definition. **The definition of mass can be stated as M=F/A. In other words, mass is how much force it takes to accelerate something.** This is a major difference between mass and weight. Something with great weight on Earth may be weightless in space (since there’s no gravity) but it will still be just as difficult to get it to accelerate. To show this we pushed my van around. First one child, then two, then three and so on got a chance to push the car. The idea being, that the more force applied to the mass of the car, the more the van accelerated. The group loved this! We will be doing more with Newton’s Second Law next week.

Check out this program. It's really neat and allows you to do some great physics simulations. http://www.phunland.com/wiki/ Home

Maria: This Monday, we looked at connections between force and acceleration, and modeled acceleration in Scratch.

The model we created during the meeting was: "If a body is in vacuum, staying still, with no friction or gravity involved, what will happen when its jet motor is turned on?"

At first, people thought the body will move at a constant speed, but then we decided it will keep accelerating (until it reaches the speed of light, or the fuel runs out, whichever comes first).

Here is the homework. Use the model you created during the meeting.

- Upload the model you created during the meeting, before making changes to it. I'd like to look at them together. - Make it possible to change the jet motor force from zero (turned off) to some value you choose. You can use the built-in variable slider. Several group members used those in their programs, so you can look at how it's done and ask these people for help. - Insert a model of a friction-type force (e.g. jello in space people mentioned during the meeting). Make it possible to change that force from zero to some value you choose. What happens to your object as two forces interact? Why? - Do you know any computer games with forces like this? - Please upload your models into the gallery http://scratch.mit.edu/ galleries/view/58724

Week six, October 19th, 2009
Jim:

Today we began Newton’s Laws. Newton’s first law is an object at rest tends to stay at rest, an object in motion tends to stay in motion. What this means is something that’s sitting there doesn’t move on it’s own accord (rather obvious) but something that’s moving does not want to stop. There must be a force that causes something moving to stop or to change direction. Gravity and friction are the most common of those forces on Earth. We also did an experiment to understand the concept of inertia. Inertia is basically how hard something is to get going or how hard it is to get it to stop. A train has a lot of inertia, a ping pong ball does not. We piled several pennies on the back of a lego "sled". When the kids pulled the string of the sled quickly, Many of the pennies were left behind and ended up right where they started. This is due to inertia. Those pennies weren't moving, there wasn't enough force to get them moving, and so they stayed where they were even when the sled moved out from under them. Then we used the same equipment, but this time we pulled slower. The pennies traveled with the sled in a nice little stack until the puller stopped pulling. Then the penny stack fell forward. This is also inertia. The stack of pennies were in motion and just because the cart stopped didn't mean the stack stopped. Think of that the next time you spill a drink in your car!! Also, I've included a couple of websites that do a really nice job using programming to model physics concepts. They are a bit tricky to figure out but quite neat once you get the hang of them.

Here's some apps from the University of Colorado that explore what we've been working on in class. Have fun! Energy Skate ParkPendulum LabMy Solar SystemLunar LanderMasses & SpringsProjectile Motion

Maria:

We had a theoretical question and a design task for homework. Theoretical question: which of the three faucet models, found in the eponymous applet in the gallery, works exactly like the gravity of this world, if not this planet? Or maybe none of them do? Why?

The design task today involves a bunch of Boolean (yes-no, or other two values) variables. I'd like you to start a simulation or a computer game about inertia, friction and gravity. Your screen can be a horizontal plane (maybe a hokey or other game field), with players looking at it from above.

1. Make your object have some "motor" (jet, sail, pushing foot...) that pushes it. Make it possible to turn the motor on and off.

2. Make it possible to switch from Galilean (or early Chinese and Islamic) to Aristotelian inertia in your model. Wikipedia has a decent short description of historical views: http://en.wikipedia.org/wiki/ Inertia

3. Make it possible to switch friction on and off.

4. Make is possible to switch gravity on and off.

Use your model to observe what happens in each of the many (how many?) combinations of the four (or however many you model) Boolean variables and the variable speed. For example, if you switch the motor off on a moving object under Aristotelean inertia with friction on and gravity off.

We will spend the next programming portion of our meeting debugging, developing and discussing our models. Jim assured me it's a challenging enough task!

--- I am adding the Scratch gallery link, comic collection, and past homework to our Wiki at @|http://physicsmathmodeling. wikispaces.com/ so we have it all in one place.

Week five, October 12th, 2009
Jim:

Today we investigated acceleration. The definition of acceleration is a change in speed or change in direction. To show this we rolled metal balls down a ramp and timed them as they reached different sections of the ramp. We saw that as the balls moved further down the ramp they continued to gain speed. They were accelerating. We also measured how far the balls went in one second, two seconds, and three seconds. We saw that the balls traveled further with each second interval. Again, they were gaining speed as they went down the ramp. Next week we will investigate Newtons First Law.

Here’s an excerpt from my “Bite-Size Physics” materials on acceleration. **Acceleration** Now let’s get up to speed with acceleration. In physics acceleration is defined as a change in velocity. In other words, it is a change in speed or a change in direction. It is how much time it takes something to go from one velocity to another. Remember that velocity is speed and direction. If you go straight ahead on your bike at a constant speed of 5 mph you are not accelerating. Neither your speed nor your direction is changing. Now, if you are stopped at a stop light and it turns green, you are accelerating as your speed increases from 0 mph to 10 mph. The same thing happens if you are traveling at a nice even 10 mph and slow to a stop. In physics we don’t use the word deceleration. We use positive and negative acceleration. Now what happens if you are in a car and it turns a corner at a constant speed of 15 mph? Is it accelerating or not? Well, its speed is not changing but its direction is, so it is indeed accelerating. Remember back when we talked about gravity? We learned that gravity accelerates things at 32 feet per second2. Now this may make a little more sense. Gravity made something continue to increase in speed so that after one second of having the force of gravity pull on something, that something has reached a speed of 32 feet per second. When that thing started falling it was at 0 velocity, after a second it’s at 32 feet per second after 2 seconds it’s at 64 feet per second and so on. It’s the old formula v=gt or velocity equals the gravitational constant (32 ft/s2) times time. If something has an acceleration of 5 ft/s2 how fast will it be going after 1 second...2 second...3 seconds? After one second it will be going 5 ft/s; after two seconds 10 ft/s; and after three seconds 15 ft/s. Again, it’s just like v=gt (v is velocity, g is the gravitational constant, t is time) but put the rate of acceleration of the object in place of g to get the formula v=at or velocity equals acceleration times time.

Maria:

We are looking at speed and acceleration models. There is a dramatic conflict between the motion in our world and the motion in computer models!

All motion in our world is continuous. Even the squirrels I impersonated yesterday, which look discrete, move continuously! There is no teleportation yet. Well, unless you are a quark.

Everything in computers is discrete. The motion in virtual worlds always consists of teleportations from one point to the next, as computers re-draw objects in new positions. Even the "glide" function in Scratch, which looks smooth to the eye, consists of tiny little teleportations!

How do you model distance, time, velocity and acceleration for virtual worlds? As usual, there are many ways. Here is your homework...

(1) Find my project, called "Three Dripping Faucets," in our gallery http://scratch.mit.edu/ galleries/view/58724 It has three different models of gravity. Which one is the closest to our world? Why? I made the trajectories visible by using Pen Down and Stamp commands from the Pen menu. Imagine taking snapshots of falling or rolling ball experiments every .5 seconds. Download the code and make a remix of it, making wind blow at the drops, at a constant velocity. What happens to the three trajectories? Why?

(2) Gravity game mechanics. Find out how your favorite games model motion: velocity, acceleration, and gravity. For that, you will probably need to make some scientific observations in-game. Why yes, I really am assigning your favorite games to play, as homework! Then share your observations at our wiki: @|http://physicsmathmodeling. wikispaces.com/ One of the best ways to share is to embed a short in-game video - either one you make, or something you find on YouTube. Snapshots work as well, or stop-motion animations. The icon for embedding videos (and widgets) into the wiki looks like a TV. If you want us to look at a particular moment from the video, note its time. I put an example of an elf jumping off a cliff in World of Warcraft, in slow-motion.

(3) Some of you looked at other people's Scratch models of gravity. This is a great practice to continue! Here is the keyword search for that: http://scratch.mit.edu/pages/ results?cx= 010101365770046705949%3Agg_ q9cry0mq&cof=FORID%3A11&q= gravity&safe=active&sa=search# 1167

(4) Math, science and programming work much better when you collaborate. Mladen Vouk, the department head of Computer Science at NCSU, told me that number one requirement from businesses to their graduates is "communication skills," because modern software projects are always group efforts. So: if you get stuck in your homework, or just want to discuss project ideas, or find a cool game with glaring gravity mistakes and want to share - find your colleagues from the group, or myself, in chats. This is a real-time addition to asynchronous collaboration tools like wikis, galleries or email. I use the following tools:


 * Twitter http://twitter.com/ mariadroujkova
 * Skype maria_droujkova
 * Gmail chat droujkova@gmail.com
 * Phone 388-1721 (evenings are better)

You can "reply all" to this message with your chat info if you want to connect to more people. You are very welcome to ask me any question, or to work together to debug your applet.

(5) I have invited everybody who gave me their emails to contribute to our physics, math and programming comics slideshow, which you can view here: http://docs.google.com/ present/view?id=ddjkthrd_ 150kvfxsdff

Week four, October 5th, 2009
Jim:

Today we began our Mechanics unit by discussing one of the most influential forces on the planet; gravity. The first thing we did today was drop two items of different weights. Which one do you think hit the ground first, the light one or the heavy one? They both accelerate at the same rate of speed and as such, hit the ground at the same time. Any two objects will do this, a brick and a Buick, a flower and a fish, a cumquat and a cow! “But,” I hear you saying, “whoa Jim, if I drop a feather and a flounder, the flounder will hit first every time!” Ok, you got me there. There is one thing that will change the results and that is air resistance. The bigger, lighter and fluffier something is, the less gravity can accelerate it and so it will fall slower. Air resistance is a type of friction which we will be talking about later. In fact, if you removed air resistance a feather and a flounder would hit the ground at the same time!!! Where can you remove air resistance? The moon!!! One of the Apollo missions actually did this (well, they didn’t use a flounder they used a brick). An astronaut dropped a feather and a brick at the same time and indeed, both fell at the same rate of speed and hit the surface of the moon at the same time. Ask someone this question. Which will hit the ground first, if dropped from the same height, a bowling ball or a tennis ball? Most will say the bowling ball. In fact, if you asked yourself that question 5 minutes ago would you have gotten it right? It’s “common” sense to think that the heavier object falls faster, unfortunately, common sense isn’t always right. Gravity accelerates all things equally. In other words, gravity makes all things speed up or slow down at the same rate. We will be discussing acceleration more in a later lesson. Remember the pendulums? The weight of the bob made no difference on the rate of swing of the pendulum. Do you see why now? Gravity causes all things to fall at the same rate of speed. Since gravity was causing the pendulum to fall, it didn’t care how heavy the bob was. Whether it was a coin or a Cadillac! All things drop at the same rate of speed. The next experiment we did was I caused one coin to drop straight down while causing another to fly forward. If they both begin their mission at the same time, which one hits the ground first. The dropping one or the moving one? The coins hit the ground at the SAME time. Is that odd or what? Gravity doesn’t care if something is moving or not. Everything falls at the same rate of speed. A bullet fired parallel to the ground from a gun and a bullet dropped from the same height at the same time will both hit the ground at the same time! Even though one may be a mile away! Seems incredible but it’s true. Gravity doesn’t care what size something is or whether or not it is moving, it treats all things equal and accelerates them downward with equal rates. Notice that I don’t say pulls on all things equally, because that’s not true. Gravity does pull on things differently. That’s why you weigh more then a chihuahua. Gravity is the attraction between two bodies, and all bodies have gravity between them. You and this computer have a gravitational pull between you. The coins and the ruler have a gravitational pull between them. Gravity, however, is a very weak force and one of the bodies has to be very, very, very, very big before a force is created. The Earth is very, very, very, very big and so things are attracted to it. The larger something is, the greater gravitational pull that something has. By the way, even though we have known about gravity for many years, scientists still have no idea what it really is. No one really knows why one thing is attracted to another and what pulls one thing towards another thing. (The above material is borrowed from my website www.bitesizephysics.com)

Here's some fun websites to play with these neat gravity concepts. __http://www.sciencemonster.com/ lunarlander/index.html__ http://www.thecleverest.com/ content/attractors.swf http://www.explorelearning. com/index.cfm?method= cResource.dspView&ResourceID= 609 Movie of an Apollo Astronaut dropping a feather and a hammer on the moon!http://www.bitesizephysics. com/Movies/Mechanics%20Movies/ fallingonmoon.html

Here's a couple of fun things to take a look at. This is a great little thing that lets you play with orbits and see the motion of bodies due to gravity. PhET My Solar System - Motion, Acceleration, Velocity, Circular Motion Here's a movie of an Apollo astronaut testing Galilleos theory.Falling on Moon

Maria:

We looked at almost everybody's models last time (except for one saving accident) and made a long list of variables you used in the models. What a show! I am impressed with the group's work! I know some of you spent hours improving the models and debugging the code. WELL DONE!

Unfortunately, someone erased the whiteboard before I had a chance to snap a picture. This will teach me to photograph things at once! Still, you probably remember types of variables:

YES-NO VARIABLES, for example, the Buffalo and the Moo variables. "To moo or not to moo - that is the question!" They are also called "Boolean" after the logician, but in logic, the values are always "True or False." http://en.wikipedia.org/wiki/ Boolean_data_type In computer science, Boolean variables take 1 and 0 values, as in this cartoon depicting a "real programmer" at work: http://www.joe-ks.com/ archives_aug2004/ RealProgrammers.jpg The joke is people usually start from high-level (word-based) languages, and then get closer and closer to the ones and zeroes the system really operates on.

QUALITATIVE VARIABLES describe of qualities or states, for example, choice of several backgrounds, or of several pendulum lengths. In philosophy and other social sciences, and this one area of math, these variables are called "categories." In the rest of math and in computer science, they are called "discrete." To work with this type of variables, you used two approaches. The first approach had the program cycle through all possibilities when the user pressed or clicked a button. In the second approach, each category had its own button, for example, numbers 1-4 for pendulum lengths. Boolean variables are a type of discrete variables.

CONTINUOUS VARIABLES describe numbers within a certain range, for example, angles from 0 to 180 degrees. There is a philosophical argument of whether computers can ever really, really work with continuous variables, because everything in computers is Boolean (0 or 1) and thus discrete. Engineers say computers get close enough to continua "for all practical purposes," and mathematicians say, "Bah! Humbug!" Some of you used continuous variables for gravity, angle or length.

~*~*~*~*~* HOMEWORK TODAY

Make a model of a situation involving gravity. If you are describing a real situation on a planet or a moon, your modeling is more challenging (since everybody knows how it feels to be on a planet), so, experiment with physical objects to observe how they really behave.

Alternatively, you can make up your own reality and its laws, and next time, we can guess what they are. From now on, we will be starting each Programming part by looking at everybody's work, as we did yesterday.

Week three, September 28th, 2009
Jim:

Today we worked on communication. Communication is vital in science in order to communicate what was done and what happened. Good communication is very difficult to achieve and I tried to give the children a chance to see how difficult it is to get somebody to understand what you're saying and how difficult it is to really hear what the other person is saying. First, I had the kids tell me how to make a peanut butter and jelly sandwich while I tried to "follow" their directions. Of course, I did everything that they said so when they said take the jam and put it on the bread, I took the jar of jam and put the whole thing on the entire loaf of bread! We had a lot of fun with that. Then we did, what I call, Communication Blocks. Here's how to do this at home. Get 2 people. Get 2 sets of 5 identical blocks. Get some sort of "screen" for both people so that neither person can see the other's blocks. Have one person be the "giver" and the other the "receiver". The person who is the giver will put his or her blocks together any way they want. Then the giver will give instructions to try to get the receiver to recreate exactly what the giver has created. After the giver and receiver think they've got it, lift the screens and see what you have. The first few times you do it you may want to use less then 5 blocks. Also allow no questions to be asked by either participant. After a few times allow the receiver to ask questions. This really is quite an eye opener and is a lot of fun. If you don't have blocks you can use any other kind of object as long as you have 2 equal sets of them.

We also did this little worksheet. I told the children that I would send a copy of it to you so that they can have you do it. Give it a try and see how you do! Please follow the following directions exactly. Do everything that the instructions say. Read all the following directions before beginning.

1. Circle the word circle in this sentence.

2. Write the third word in this sentence here.

__3. Draw a large square on the back of this paper.

4. Draw a large triangle on top of the square on the back of this paper.

5. Draw a rectangle inside the square with a short side touching the middle of the bottom of the square on the back of this paper.

6. Draw a small square to the right of the rectangle in the large square on the back of this paper.

7. Draw a circle above the left side of the triangle.

8. Ignore every single instruction on this page but this one. Turn your paper over and draw a big smiley face on the paper. There should be nothing on the back of this page but one big smiley face.

Maria:__

This week, the modeling task was to have models take input from the user in the form of variables. Different people used different methods for input, mostly keyboard buttons and mouse clicks, but some experimented with on-screen buttons as well. The homework is to finish what you started, and to upload your applets into our gallery, which you can find at http://scratch.mit.edu/ galleries/view/58724 Next week, we will start from looking at everybody's applets, making the master list of everybody's variables, and using it to discuss the idea of LAWS, from the math point of view statements about relationships among variables, in real and virtual worlds. For those of you interested in game design, laws create game mechanics http://en.wikipedia.org/wiki/ Game_mechanics

Please put a note of some sort on the screen of your model, explaining what input it takes (e.g. keys 1-6). These applets are open source, and many people will probably be using them. During the meeting, each author explained his or her model's input in words.

I am very happy with the atmosphere of creativity and cooperation in the group. The models are getting more complex and involved. I can't wait to see everybody's variables. I bet we have a dozen or two different ones among us!

~*~*~*~*~*

I am reading an extremely interesting study by Jo Boaler, comparing two schools in Britain. Both schools started with similar populations of working class kids.

In one school, teachers made choices for students and had them work out of standard books, following a set curriculum. There, nobody likes math much, and most people learned to go through procedural motions just doing what they were told. Teachers and students believed it was necessary for success, while boring and personally meaningless. Their time on task was above 90%, but they often faked the learning part.

In the second school, students had complete choice of whether or not to do tasks (projects only), and which projects to do, and how deep to engage with projects. There, about a third of people loved their math, about a half liked it fine (caring more for some projects), and the rest hated the openness and choices. It was mostly boys who did not like to constantly make decision about projects and come up with ideas. Also, time on task was lower there, with anywhere from 30 to 70% of students doing non-math things at any given time.

The second school is more successful mathematically, especially on conceptual problems. However, that sixth of the population totally hating it bothers me. There should be a happy medium between complete openness and routine, procedural work people can do when they feel in a funk or less inspired. The researcher noted, "students were either interested and working, or disinterested and not working."

We started the Modeling part of the unclass very open. I plan to keep a lot of openness and freedom there, because both mathematics and modeling benefits from it. However, I also want to provide opportunities for people to work all the time, including the times when the inspiration does not strike.

Study reference: Boaler, J. (2002). Experiencing School Mathematics: Traditional and Reform Approaches To Teaching and Their Impact on Student Learning, Revised and Expanded Edition (Rev Enl.). Lawrence Erlbaum.

__Week two, September 21st, 2009__
__Jim:__

Remember, last time we discussed the scientific method; observation, test, collect data, and report results (other wise known as Orange Hippos Take Classes Regularly). Today we used the method to discover a couple of things about pendulums. We introduced two new terms. One was constant variable and the other was changing variable. A variable is a part of your experiment, like the coin in the underwater presidents experiment or the bird in the balancing bird experiment. If it is a constant variable, it stays the same for every trial of that experiment. For example, we always used the same penny in the Underwater Presidents (my name for the drops on a penny experiment). That variables never changed. A changing variable is what you change for each trial. It is often what you are testing for, “If I change this, what happens to that?” For example, in the Underwater Presidents experiment, if we did the experiment several times, and one time we tried water in the dropper, the next time we tried vegetable oil, the next time we tried corn syrup, the changing variable would be the liquid we are using in the droppers. When you do an experiment you have to try very hard to keep all variables constant except for the one you are testing for. If you don’t keep all but one constant you won’t know why you are getting the results you’re getting. If you change the size of the coin, and the type of liquid with the Underwater Presidents experiment you will have a hard time knowing if its the change of coin or the type of liquid that’s causing more drops on the coin. We did two experiments today with pendulums. In one, our changing variable was the length of the string. The weight, the string itself, the room we did the experiment in, etc. all remained constant variables. The groups made a hypothesis before beginning the experiment as to whether the length of string would increase, decrease, or make no difference on the amount of swings in 10 seconds. After doing the experiment it was discovered that the shorter the string, the greater the number of swings. For the second experiment, we changed the weight on the end of the pendulum. The string length and everything else remained constant. The group made a hypothesis of whether or not an increase in weight would increase, decrease or make no difference on the number of swings. Surprisingly, the weight made no difference in how many swings that pendulum made! We will discuss why that is when we discuss gravity in a couple of weeks.

__Maria:__

We are continuing with the general scientific method for the physics part, and exploration of the programming environment for the modeling part. On September 21st, the discussion prompt for the scientific method was the pendulum experiment, and we made first models of pendulums in Scratch. For your first homework, please:

1 - if you have not yet, create an account at the Scratch site 2 - upload the model you made (or several versions) to this gallery, which we will be using for the activities: http://scratch.mit.edu/ galleries/view/58724 3 - think of what game mechanics could use a pendulum

Next time we will be building on models, so we need them in the gallery to be able to look at them quickly with the projector, without always getting up and crowding around laptops. You can also put other Scratch sketches you make into that gallery.

To recap, we saw examples of several major approaches to programming a pendulum, including direct animation (creating an instance of every event and then going through them in a slide show manner), repetitious code (turn, turn again, turn again), pseudo-random motion (one object following another, which is programmed to move in a certain way), infinite cycles (turn forever), and terminating cycles ("turn given number of times" or "turn until a certain angle is reached"). This is a nice example space to talk about programming methods - we started the discussion a tiny bit, but will continue more next week. Programming approaches parallel the ways people think about the world and make sense of it, but are mediated by one's programming and visualization/storytelling skills.

Next week, we will incorporate variables into our models. The goal will be for the models to take some sort of variable input. You can do it in a variety of ways. The goal I'd like us to explore after that was to make realistic models - a pendulum that works on-screen as a physical pendulum works on Earth - and sci-fi models of various sorts.

Here is Jim's plan for the next eight weeks: Communication (how difficult it is to be clear and specific when communicating to others. A very important topic in science but also in life in general.) Gravity Newton's First Newton's Second Newton's Second (a little deeper) Newton's Third Momentum Impulse

Yesterday, several of us talked with Carolyn Mabry, a wonderfully geeky hoola hoop event organizer - we watched her spinning hoops that were on fire, next to our drumming circle. Beautiful! It turns out she is doing a physics investigation into the laws, momentum and forces involved in spinning (and making) her hoops. It's related to pendulums, but more complicated, so let's get those Newton's Laws, momentum and impulse uncovered before we meet Carolyn - because she's coming to visit! She will bring enough hoops for all of us to experiment, and will chat about hoop physics with us. We will do it as a class party, on the 11th week, at the same time.

See you in a week! Please call me 388-1721 or email with questions and class ideas!

__Week one, September 14th, 2009__
__Jim:__

Today we began a unit on the scientific method. During the next few weeks we are going to go in depth into the scientific method and experiment design. My hope is that by the end of this unit the kids will be comfortable with the process of science and perhaps encouraged to try it at home. This week we went over the basics of the scientific method. Which is: ObservationHypothesisTestCollect DataReport Results Observation means what do you see, or hear, or smell, or feel. What is it that you’re looking at? Is that what it usually does? Is that what it did last time? What would happen if you tried something different with it? Observation is the beginning of scientific research. Once you see something, you can then form a hypothesis. All hypothesis really means is “guess”. Hypothesis is an educated guess. Hypotheses aren’t right or wrong they are just your best guess. To see if your guess is correct, you need to do the next step in the scientific method, test. The test is just what it sounds like, running experiments to see whether or not your hypothesis is correct or not. We’ll talk in more detail about tests in the next lesson. As you do your tests you need to collect data. That means collecting the numbers, the measurements, the times, the data of the experiment. Once you collect your data you can take a look at it, or in other words analyze it. Once you analyze your data you can report your results__. That basically means tell someone about it. You can put you data in a chart or a graph or just shout it from the rooftops! Here’s a great way to remember the 5 steps. Remember the sentence “Orange Hippo’s Take Classes Regularly”. The first letter in each word of that goofy sentence is the same as the first letter in each step of the scientific method.

Maria:

What a great unClass! We started with Jim's great overview of what science is all about (more from him) and then went on to introduce Scratch. I do so love listening to a roomful of people happily programming together.

I'd like group members to register at the Scratch site and then add your projects to the gallery I just made for us: http://scratch.mit.edu/ galleries/view/58724 This way, group members can continue working on the projects they started together, and we can quickly project everybody's work when we meet. This site also has a great support community with an active forum.

Next week, we will be making physics models in Scratch. See you on Monday, September 21st, at 1pm. Parents are welcome to stay and observe, or bring their laptops and join the fun.