system (02:12:23:816 PM): Johann has joined Babylon.
system (02:12:29:854 PM): Johann left the Main chat room.
system (03:32:53:561 PM): Ian has joined Babylon.
system (03:42:21:318 PM): Mod2 has joined Babylon.
Mod2 (03:42:39:114 PM): Hey, Ian

Ian (03:42:47:007 PM): Hey, Mod2.  :^D
Ian (03:42:51:620 PM): Where's Mod1?
Mod2 (03:43:09:399 PM): I though Mod2 sounded more matematical ;-)

Ian (03:43:27:256 PM): Ah, like Mod3.14...
Mod2 (03:43:34:838 PM): I am still trying to fix my classpath so I am running the applet

Ian (03:43:52:098 PM): Has something changed since last time?
Mod2 (03:44:59:019 PM): I installed JRun to see if I could work on the Applet and that must have change my classpat settings but they look o.k. to me

Mod2 (03:45:17:225 PM): Anyway, I am going to have to rely on you to create multiple rooms this time

Ian (03:45:45:698 PM): Okay.
system (03:46:04:771 PM): Ian left the Main chat room.
system (03:47:53:220 PM): Ean has joined Babylon.
system (03:48:02:143 PM): Ean left the Main chat room.
system (03:48:52:529 PM): Mod1 has joined Babylon.
system (03:48:55:480 PM): Tyler has joined Babylon.
system (03:49:00:843 PM): Mod1 left the Main chat room.
system (03:49:02:548 PM): Tyler left the Main chat room.
system (03:52:33:611 PM): Ian entered the Main chat room.
Mod2 (03:53:41:255 PM): Ready, then

Ian (03:54:24:372 PM): Okay, so where is everyone?
system (03:56:59:597 PM): Mod3 has joined Babylon.
Mod3 (03:57:41:917 PM): O.k. I sort of fixed my classpath so now I am running tha app and will be able to save the canvas and create rooms

Ian (03:57:51:942 PM): Yay!
Ian (03:58:04:564 PM): Assuming anyone shows up, so there's something to save...
system (03:58:04:605 PM): Mod2 left the Main chat room.
Mod3 (04:00:50:999 PM): right!

Mod3 (04:01:10:616 PM): did mijit say he/she will come?

Ian (04:01:31:853 PM): He didn't.  He wasn't very active last time, once we got off the stuff he wanted to learn.
system (04:02:02:489 PM): Mod2 has joined Babylon.
Ian (04:02:09:084 PM): And we don't know who he is, so we can't invite him.  :^/
system (04:02:10:035 PM): Mod2 left the Main chat room.
Mod3 (04:03:28:156 PM): true.  I send the "PIs" the changes to the IRB protocol today so that we can register people and invite them.  We will see how fast that gets approved

Ian (04:04:28:433 PM): Maybe we should talk about math.  
Mod3 (04:05:27:126 PM): so you figure out why substitution works?

Ian (04:06:00:100 PM): Not in a way that I can explain to someone who doesn't already get it.
Mod3 (04:06:22:209 PM): ;-)

Ian (04:06:25:420 PM): I suppose part of what's happening is that you're dragging a context along with the thing yo'ure substituting.
Ian (04:06:33:467 PM): But that's not stated anywhere.  
Ian (04:06:39:586 PM): It's like a hidden assumption.
Ian (04:06:48:309 PM): And I'm not sure how to make it unhidden.
Mod3 (04:09:02:115 PM): By "context" you mean..

Ian (04:09:02:396 PM): Is this spring break?
Ian (04:09:26:878 PM): Drexel is on break, and I know some other schools are.  (Kristina Lasher was at the Forum yesterday because her school was on break.)
Ian (04:09:47:288 PM): Maybe everyone's on vacation, dyeing Easter eggs and stuff. 
Mod3 (04:10:10:143 PM): You are right

.  I just stopped by the Robotics Competition during lunch break and that is usually done during the break so that teams can travelIan (04:10:25:064 PM): Did you see anything interesting?
Mod3 (04:10:56:924 PM): Sure... it was my first time so I liked that the task is now collaborative. 

Mod3 (04:11:10:575 PM): Three teams form an "alliance" against other three teams

Mod3 (04:11:44:688 PM): and the task is much more strategic than just pushing blocks somewhere or smashing somebody else's robot

Ian (04:12:07:916 PM): That sounds pretty cool.
Ian (04:12:25:888 PM): So one robot is trying to do something, and the others are trying to stop it?
Ian (04:12:45:184 PM): Sorry, three on three.
Mod3 (04:12:46:523 PM): They start with a 15 second "authonomous" period

Ian (04:12:47:996 PM): I missed that.
Ian (04:13:01:643 PM): What kids of tasks are they doing?
Mod3 (04:13:08:132 PM): which sounds awfully short to me

Mod3 (04:13:28:492 PM): and then the teams do a bit of divide and conquer type of task

Ian (04:13:31:570 PM): Robots may experience time differently than you and I. 
Ian (04:13:48:808 PM): But are they being controlled from the sidelines?
Ian (04:14:12:853 PM): I thought the point of a robotics competition was to turn them loose without guidance. 
Mod3 (04:14:19:780 PM): but it is not quantity that makes them win but whether the things that they are moving around are position in specific ways in relation to what their oponents are doing

Mod3 (04:15:00:768 PM): Well, after the 15 seconds they are under "driver control" for 2 more minutes

Mod3 (04:16:54:854 PM): Here is the URL with the info:

Mod3 (04:16:57:935 PM): http://www.usfirst.org/robotics/doc_updt.htm

Mod3 (04:18:10:076 PM): Ian, do you have access to the website traffic reports?  I am wondering if you can determine if it is spring break for Math Forum users that way

Ian (04:19:15:596 PM): I don't really know where they are.
Ian (04:20:33:166 PM): Looking at the Dr. Math stats, they look pretty stable.  No big drop in the last week. 
Mod3 (04:20:59:274 PM): well, it seems as if today is not going to be too active

 around heresystem (04:21:08:903 PM): Nobody has joined Babylon.
Ian (04:21:26:243 PM): Okay, that's me.  I'm just checking to make sure the link works. 
system (04:21:33:581 PM): Nobody left the Main chat room.
Mod3 (04:21:54:735 PM): good thinking, I made that mistake

 once with the SAT chatsMod3 (04:24:24:020 PM): Ian, just curious, 

are you drawing on the canvas?  I have seen the message "drawing: Ian" but I dont see anything on the canvas.  Ian (04:25:52:903 PM): I'm not.  I see that message too.  I figure I just put the cursor in the canvas at one point, and never did anything to undo that. 
Ian (04:26:18:622 PM): I just invited a kid who wrote to Dr. Math about exponents to chat.  I don't know if he'll do it, though. 
Mod3 (04:27:37:464 PM): nice... 

Mod3 (04:29:42:422 PM): I was reading in k12.ed.math the responses that a kid got about why we square the differences to the mean in statistics instead of taking the absolute value and it is really nice that he gets from the super answer from Dr. Professor of Biomolecular Engineering to lay man (probably) who simply says it simply is so

Mod3 (04:30:40:100 PM): but asynchronous discussions really lack on reciprocity... they are really hard I think

Ian (04:31:04:157 PM): What do you mean 'reciprocity'?
system (04:32:22:873 PM): RedCisc has joined Babylon.
Ian (04:32:39:241 PM): Hi Red!  Welcome.
RedCisc (04:32:58:947 PM): Hello
Mod3 (04:33:02:880 PM): Hi, RedCisc!

Ian (04:33:04:268 PM): What's on your mind?
RedCisc (04:33:41:775 PM): I have a question that I just submitted to Dr. Math.  Can I discuss it with you?
Ian (04:33:53:198 PM): Sure.
Ian (04:33:56:412 PM): What's the question?
RedCisc (04:34:15:658 PM): Ho, while I go copy/paste it 
system (04:34:19:676 PM): ello has joined Babylon.
system (04:34:22:891 PM): ello left the Main chat room.
RedCisc (04:36:42:791 PM): I can't find it.  So I'll reask it.  2 cars are at a rest stop on the highway.  One car, A, leaves 20 minutes before the second car, B.  Assuming that car B drives 65 mph, how long and how far will it take be to overtake A?
Ian (04:37:13:767 PM): Do you know how fast B is going?
RedCisc (04:37:18:309 PM): I know that d=r*t
Ian (04:37:27:619 PM): I mean, do you know how fast A is going?
RedCisc (04:37:52:881 PM): yes. B, the chase vehicle is going 65 mph.  I do not know how fast a was going.
RedCisc (04:37:59:356 PM): no
RedCisc (04:38:06:669 PM): to the speed of A
Ian (04:38:10:143 PM): Well, suppose A is going 100 miles per hour.  B will _never_ catch him.
RedCisc (04:38:33:376 PM): true.  but how can math be used to determine that?
RedCisc (04:40:16:049 PM): I somehow think the formula for A should be something like d=r*t+20
Ian (04:40:36:915 PM): Well, you know that A was traveling for 20 minutes, right?  So that's 1/3 of an hour.
RedCisc (04:40:46:174 PM): yes
Ian (04:40:56:927 PM): If he was going 60 mph, that would be 1/3*60, or 20 miles.
Ian (04:41:12:230 PM): If he was going 90 mph, that would be 1/3*90, or 30 miles.
RedCisc (04:41:13:975 PM): correct assuming 60 mph
Ian (04:41:14:193 PM): And so on.
Ian (04:41:46:675 PM): Does that make sene?
Ian (04:41:49:312 PM): sense
RedCisc (04:42:16:654 PM): yes it does but how can we build what makes sense into an equation?
Ian (04:42:37:172 PM): Well, suppose we don't know his speed.  Maybe we just call it 'v' (for velocity).
Ian (04:42:48:381 PM): At v mph, how far does he go in 1/3 of an hour?
RedCisc (04:43:21:324 PM): ok
Ian (04:44:07:850 PM): V is the speed, 1/3 hr is the time.  What's the distance?
RedCisc (04:44:52:787 PM): we don't know
Ian (04:45:07:664 PM): Well, you have the equation distance = speed * time.
Ian (04:45:20:537 PM): What if you put 'v' in for speed, and 1/3 in for time?
RedCisc (04:46:51:500 PM): so, is the only solution to build a table of possible speeds to determine the distance?
RedCisc (04:47:03:520 PM): distances
Ian (04:47:05:228 PM): No, you can just find a result in terms of v. 
Ian (04:47:35:601 PM): You'll end up with an equation, where if someone says "The car was going such and such a speed", then you'll be able to put that value into the equatino, and out will pop the time. 
Ian (04:48:01:434 PM): But building a table can be a good first step.  Can you pick a few speeds, and solve it for those?
RedCisc (04:48:39:928 PM): let me fill you in on the circumstance so you may envision the problem.
Ian (04:48:49:296 PM): Okay.
RedCisc (04:50:31:088 PM): last summer my wife and i travelled to Cape Cod in separate cars. we stopped at a restarea on 95.  she left about 20 minutes before me.  as i drove along i was trying to figure out how fast i needed to drive to catch her and how long would it take me?  
RedCisc (04:50:55:543 PM): i didn't know how fast she was going
Ian (04:51:40:616 PM): Then the most you could do would be to do what we're doing here, which is set up an equation to describe what's going on.
Ian (04:51:53:813 PM): But let's try another approach.
Ian (04:51:55:622 PM): Okay?
RedCisc (04:52:34:089 PM): sure. i have time if you do
Ian (04:53:22:997 PM): Suppose I'm 10 miles away from you, and you're travelling at 5 miles per hour.  How long will it take you to reach me?
RedCisc (04:54:02:288 PM): hang on
RedCisc (04:54:44:338 PM): 2 hours
Ian (04:55:26:511 PM): Right.  Now, suppose you're traveling at 10 miles per hour, but I'm moving away from you at 5 miles per hour.  Now how long will it take?
RedCisc (04:56:26:428 PM): d+5=10*t, correct?
Ian (04:57:09:739 PM): Not really.  The key idea here is that it will _still_ take you two hours.
Ian (04:57:26:595 PM): Why?  Because the _difference_ in our speeds is still 5 miles per hour.
RedCisc (04:57:33:688 PM): i got it
Ian (04:58:08:095 PM): The trick is to forget about where we are relative to the _ground_, and focus on where we are relative to each other.
Ian (04:58:35:603 PM): So, your wife has a head start on you.  If you travel the same speed, will you ever reach her?
RedCisc (04:58:44:816 PM): correct
Ian (04:59:46:794 PM): We have two things that are important here.  There's the distance she gets as a head start, and the _difference_ in your speeds.
RedCisc (05:00:11:211 PM): right, d and r1 vs. r2
RedCisc (05:00:27:486 PM): or rA vs. rB
Ian (05:01:02:263 PM): Her head start is just 1/3 of an hour times her speed, r1. 
Ian (05:01:18:449 PM): And the rate at which you're catching up is (r2-r1) mph. 
Ian (05:01:55:727 PM): So the question is:  If you have to travel a distance of (1/3)r1, at a speed of (r2-r1), how long will that take you?
Ian (05:02:24:521 PM): Now, that looks complicated, but you've already answered a question like it using numbers:  If you have to go 10 miles at 5 miles per hour, how long does it take?
Ian (05:02:27:483 PM): How did you solve that?
RedCisc (05:03:30:704 PM): 1/3r1 = (r2-r1)*t
Ian (05:03:58:247 PM): That's the equation that describes the situation.
RedCisc (05:04:23:134 PM): so, 1/3(10)=(10-5)*t
Ian (05:05:05:580 PM): Well, that's if I set off at 5 mph for 20 minutes, and you follow at 10 mph.
Ian (05:05:24:005 PM): If I set off at 60 mph, and you follow 20 minutes later at 65 mph, what would it be?
RedCisc (05:06:23:562 PM): how about 1/3(60)=(60-65)*t
Ian (05:06:41:959 PM): It looks like you mixed up r1 and r2 on the right side.  
RedCisc (05:06:50:773 PM): ok
Ian (05:07:17:978 PM): Otherwise, yes, that's right:  (1/3)(60) = (65-60)t.
Ian (05:07:39:609 PM): Which simplifies to 20=5t, or t=4.
RedCisc (05:07:41:126 PM): so the answer is 4
RedCisc (05:07:49:446 PM): miles?
Ian (05:08:10:009 PM): Right.  With those speeds, it would take 4 hours to catch up.  With different speeds, you'd get a different answer.
RedCisc (05:08:35:967 PM): too bad we can't test this
RedCisc (05:08:41:896 PM): or can we?
Ian (05:08:42:197 PM): What do you mean?
RedCisc (05:09:58:130 PM): is there a way to log this chat?
RedCisc (05:10:06:631 PM): copy/paste?
Ian (05:10:32:784 PM): You can just select the whole thing, and then cut and paste into a text file.
RedCisc (05:10:41:408 PM): ok
RedCisc (05:10:49:287 PM): can I ask anothewr question
RedCisc (05:10:52:759 PM): easier
Ian (05:10:57:063 PM): Sure.
Ian (05:11:04:575 PM): You have a handle on the other thing?
Mod3 (05:11:25:948 PM): RedCisc, I wonder how you could test the equation

RedCisc (05:12:16:642 PM): believe it or not I teach hs math.  i am interested in the drexel advanced degree. is it all online?  how much? is it an MS in Math or math education?
Ian (05:12:22:383 PM): Well, you could go out and do that experiment... but it would take 4 hours!
Ian (05:12:31:104 PM): At smaller speeds, you would need less time. 
RedCisc (05:12:31:605 PM): ha-ha
RedCisc (05:12:36:509 PM): and a wife
Mod3 (05:12:39:830 PM): lol

RedCisc (05:12:49:589 PM): driving :-(
Ian (05:12:50:138 PM): Or just a friend.
Mod3 (05:13:10:447 PM): or a computer simulation, right?

Ian (05:13:19:332 PM): What's interesting is that the equation is actually more reliable than the test.
RedCisc (05:13:19:875 PM): there ya' go
RedCisc (05:13:32:046 PM): my summer project
Ian (05:13:38:832 PM): Right, you could do a simulation.  But you'd use equations to set up the simulation, so you'd be using equations to test equations.
RedCisc (05:13:48:798 PM): true
Ian (05:14:01:995 PM): You could use speeds measured in feet per second.
Mod3 (05:14:05:894 PM): a computer simulation could test speeds greater than 65 but I wouldn't recommend that in real life... especially for the wife

Ian (05:14:10:241 PM): But the trick is measuring those speeds accurately.
Mod3 (05:14:34:715 PM): right

Ian (05:14:52:236 PM): Model trains could work nicely.
RedCisc (05:15:03:565 PM): mod3 would be the moderator
Ian (05:15:16:819 PM): Assuming you can get two guys on the same track to go different speeds.  I don't know if model trains work that way.
Mod3 (05:15:18:759 PM): sorry, I interrupted. Y

ou had another question, right?Ian (05:15:23:383 PM): Yeah.
RedCisc (05:15:35:808 PM): about drexel
Ian (05:16:03:283 PM): Oh, about getting a graduate degree?
Mod3 (05:16:04:768 PM): Ah!  

Ian (05:16:25:674 PM): I have no idea what that would cost.  If you play your cards right, it would be free.
RedCisc (05:16:42:867 PM): how so?
Ian (05:17:02:605 PM): In technical fields, graduate students are often given stipends and tuition waivers.  
RedCisc (05:17:18:858 PM): and my union would probably pay
Ian (05:17:29:199 PM): There's always that.
RedCisc (05:17:30:814 PM): is it math or math education?
Ian (05:17:47:876 PM): You could do either.  No one would pay you for math education, though.
Mod3 (05:17:50:586 PM): are you talking about a program you saw online?

RedCisc (05:17:59:279 PM): yes
RedCisc (05:18:04:192 PM): mod3
RedCisc (05:18:06:292 PM): yes
Ian (05:18:33:335 PM): The thing to do would be to call up Drexel and ask them what your options are.
Mod3 (05:18:35:319 PM): was it in the general graduate catalog?

RedCisc (05:18:54:433 PM): hang on
Mod3 (05:18:58:353 PM): I agree with Ian

Mod3 (05:19:47:840 PM): Hey, RedCisc we had a question for you

RedCisc (05:19:58:523 PM): right now i teach computer engineering and our enrollments are down.  i have been assigned to the math dept. temp..  
RedCisc (05:20:08:449 PM): go ahead, ask
Mod3 (05:20:32:644 PM): you said you work in an high school, right?

RedCisc (05:21:18:673 PM): actually it is a "middle college".  HS students taking college level courses for transfer
Ian (05:21:48:140 PM): That sounds like an interesting set up.
Mod3 (05:21:52:754 PM): interesting... I was wondering if high schools taught computer engineering

Mod3 (05:22:12:353 PM): but in a "middle college" makes more sense

Mod3 (05:23:04:575 PM): so the IT craze is fading and not as many students are interested in computers these days?

RedCisc (05:23:07:419 PM): it is fun, but the jon market is not attracting students.  On the other hand their math skills are so poor that they need a lot of remedial math.  If I go back to school and major in math then i can transfer to the math depart. and live happily ever after.
Mod3 (05:23:32:752 PM): interesting.

Mod3 (05:24:08:699 PM): Do you think that your students could benefit from solving math problems collaboratively with kids in other parts of the country?

RedCisc (05:24:23:574 PM): I live in CT, so I am looking for a degree that I can get online from a reputable university
RedCisc (05:24:31:226 PM): yes, but
RedCisc (05:24:37:501 PM): big but
RedCisc (05:25:21:998 PM): many issues about cohort solutions, as I think about it
Ian (05:25:22:555 PM): What's the 'but'?
Mod3 (05:25:36:712 PM): "cohort solutions"?

RedCisc (05:26:01:035 PM): 1) technology.  not all schools are equipped to use computers interactively
Mod3 (05:26:19:115 PM): true

RedCisc (05:26:48:882 PM): 2) class time.  I have my students for 90" twice a week and there is not enough time to cover my required material
Mod3 (05:27:57:240 PM): I see.  Do you ever use  our Problems-of-The-Week with your students?

RedCisc (05:29:40:388 PM): I do.  We play the Amazing Math race.  Teams race around the world by solving POWs.  I incorporate roadblocks and detours, just like the CBS show.  I have found that entertaining them is crucial to educating them.
RedCisc (05:31:30:911 PM): this has been cool.  when is your next chat?
Mod3 (05:32:12:552 PM): Next thursday, same time.  

RedCisc (05:32:31:519 PM): do you work at drexel?
Mod3 (05:32:32:225 PM): Usually we get students but I think that we forgot this time that it is spring break

Mod3 (05:33:21:691 PM): Thanks for stopping by

RedCisc (05:33:50:568 PM): Thank you :-)
system (05:34:06:163 PM): RedCisc left the Main chat room.
system (05:51:28:369 PM): guest has joined Babylon.
system (05:52:08:691 PM): guest left the Main chat room.
Ian (05:52:28:707 PM): Nope!
system (05:54:27:380 PM): Ian left the Main chat room.
system (05:54:39:278 PM): Mod3 left the Main chat room.