CS and Algorithms

Last year I knew I did a subpar job on teaching students how to write algorithms to prep their code. How do I know? Thanks for asking. I know because one of my top coding students mentioned after that year something about someone talking about this weird word, "algorithms", and she didn't know what it meant. Who was HER poopy teacher? ME!

So this year in my CS1 class, for their programs they are writing, I have made 3 extra slots on the sheet under each code:

Algorithm (signed off by Ms. D) ____________________
Code (checked by another student) _________________
Code (checked by Ms. D) ________________________

I also had a discussion about the code-checking by someone. I mentioned that if I was ultimately asked to sign off on a code, and it wasn't working, then the "signer offer" would get the BIG FROWNY FACE OF DISAPPROVAL.

Their algorithms are getting better. They started out just regurgitating my words. This allowed for discussions of algorithms being like "steps in a recipe". You wouldn't say: walk to the fridge to get the eggs to crack 2 open into the mixture. You would say: beat in 2 eggs.

I also like the fact that their code has to be checked by someone else. They then get to talk with others and see others' code and practice the art of checking code for bugs and direction following.

Teacher Mistakes and Teacher Voice

I make a lot of my own materials, and though I check things, I am human and make mistakes on keys and answer banks and such. Now I'm not saying that it's 50 bazillion mistakes on every assignment, but still.

I've just realized this year that that could be thought of as a good thing. My kids now know to be skeptical if their answer doesn't match mine. I hope that lots of them stop and think and redo their work and then in their mind if they can convince themselves that they have done no wrong, then they ask me to check things. This way: they gain confidence in their abilities, they learn to trust themselves, they don't always take the printed word at face value, they practice polite conversation in the how they approach me. Sometimes I'm NOT wrong even if they've done all this, but I use this as an opportunity to thank them for checking and to say that THIS TIME I was not wrong.

In a related type of situation, at various times when I ask questions of kids in class, and they answer, and the answer is correct, I put on a scrunched, disbelieving face and ask if they're sure or if that seems like the right answer. I've done this often enough that they stop and redo their thinking in their heads, and MOST times they go against the "ADULT" voice and say YES, that is the correct answer. Again hopefully they're being trained to stand up for themselves and their thinking.

Okay, ending with a silly joke that made all of us laugh on a much needed stressful day last week:
Q: What's brown and sticky?
A: A stick.

Calculus Practice

I'm trying to incorporate more AP Calculus multiple choice style questions throughout the year this year. I've scanned for various released documents and then changed them up with different problems but same intent. I guess this is kosher. We are not supposed to publish secure documents or let the kids take them home. I have not done that, but then I still am feeling antsy because the kernel of the ideas came from secure documents. Anyone have an opinion on that?

Here is what we/they had for homework recently. I like my last question (not from another source). I realized that the students were still not clear on the distinction between the derivative being the GENERAL tangent slope equation for ANY x versus a SPECIFIC slope at a SPECIFIC x using the general equation.

 

 

"Baby" Applications of Trig Functions

We just finished learning how to solve all sorts of basic trig equations (cos ___ = #, cos # = ____). We'll get to equations soon, but we wanted the students to see some applications right away. I didn't want the standard: Billy is standing 5 feet away from a tree and how tall is the tree problems from geometry.

I searched in my favorite precalculus textbooks for some ideas, and found some applications under the GRAPHING and TRANSFORMING of sine wave functions/equation section. With a bit of fiddling, I adjusted the problems, so that the students could just find the angle or plug in the angle.

We first had a discussion on the cyclic behavior of sine. Then we brainstormed as to what in real life gets bigger then smaller then bigger and on and on. Then I showed them this sheet. We made sure to discuss how in algebra when you are solving for a variable you have to isolate it by undoing what's being done to it. Then I mentioned that this is JUST like solving for "x" in algebra, but on "steroids".

Voila! New problems for the kidlets to tackle:

Trigonometry on the Calculator

I came up with a memory tool that I hope will help the kids remember which process to use when solving/evaluating on the calculator:

csc ____ = 5    versus     csc 25 =____

It all seems to get jumbled up together in their heads after they learn various equations on the calculator.

Entering either one on the calculator involves a reciprocal somehow, and they mix up when to reciprocate. For the first one:

 csc ____ = 5     you enter:   sin ^-1 (1/5)

For the second one:

 csc 25 =____     you enter:   1 / sin (25)

Here's what I hope will stick:

For the first one:

csc ____ = 5     the BLANK is in the MIDDLE,
so the RECIPROCAL is in the MIDDLE   sin ^-1 (1/5)

For the second one:

 csc 25 =____     the BLANK is on the OUTSIDE,
so the RECIPROCAL is on the OUTSIDE   1 / sin (25)

Many more ways to mess up, but maybe this will fix one problem.

A Nice Reminder

For the past few years, I knew which semester the students were taking P.E. For several months, they would waddle slowly into class and groan as they tried to sit down. "My butt hurts" ... "Ow" ... "50 burpees!" ... "walking lunges!" They'd seemingly "complain" about the PE teacher, and in a wide-eyed manner, regale others with astonishment at what difficult physical feats they were required to perform. This would happen basically all semester, whichever kid, whichever semester they had P.E.

Fast forward to this year. That teacher is still around, but some of the students now have a new P.E. teacher. This is what one kid told me after a few weeks had passed: We've asked her to work us harder. We want her to be tough like Coach C. She DID ramp it up a bit, but it's still not as challenging.

Huh.

Maybe what we hear as complaints is just a badge of honor that the kids are touting as they process in wonder at what hard things they can do when they are "forced" to. They are saying it out loud as sort of a "go me" type of conversational pat on the back. They complain, because they are humans and teens, but secretly they crave the challenge.

So maybe when we hear that they have SO much homework and the problems are SO hard, then we should reply, "yes, and look at how great you are doing by struggling and keeping at it". Work those brain muscles!

Correcting HWK

I'm trying something new this year both in AP Calculus and in Precalculus when the students go over their homework, and I think it's a win for me/my class/my students.

For the past several years in precalculus, I would work out the homework, place the key on the document camera, and we would painfully and slowly go over the answers while the students corrected in a different colored pen. I grade on completion since I think homework should be a time to practice. I understand (obviously) there are different philosophies on this, but I feel this works in my situation. I do watch for kids sneakily copying things in pencil and passing it off as their own. I do look over the homework later to see if they attempted all problems.

Anyway, this always took way too much class time, and most likely, students were probably not looking as closely as possible to solutions, and everyone most likely had different problems they were confused about, so some were sitting around needlessly while they waited for their particular problem to be shown on the document camera.

This year, I take my key and make enough copies for 1 per 2 kids. They silently glance over the key and correct their work. This has gone MUCH faster than before. Also, kids can see how I lay out my work and have the time to concentrate on the particular problems they need to see and have good examples of process and thoroughness (or maybe I'm just being idealistic).

I've also done this in calculus. I used to just collect the homework, then put the worked out key on the LMS site for them to check later. I'm guessing that by the time they got back the homework by the following class and had more homework to deal with, they never checked the old homework. This year in my flipped class, they have the key on their table and can carefully go over it and ask questions right when it is still fresh in their minds. Again I like the fact that they have constant reminders of how the work should look if it's thoroughly done.