Unit 3 Reflections: Icy Hot Lab

Snow days.  Don't get me wrong, I love them... but they sure are making it hard to get through everything before the EOC.  The EOC date does not change no matter how many days we are out.  Yesterday was another snow day.  We picked up today with the Icy Hot Lab, and had to cram it into one day.

I haven't gotten to begin this unit as I would have liked with all the interruptions.  Wednesday I was missing a large portion of my classes due to paperwork for the ACT.  All we really got through was the Energy Reading Study Guide.  We didn't even have enough time to discuss the reading and study guide in class, so I had no idea how much understanding they had of energy.  Not surprisingly, my thinking-phobic, non-conceptual students love assignments where they just have to hunt and peck for the answers.  It was the best "work" I've seen out of them this year.

Today, I put some of the main points from the reading into a PowerPoint-- because I feel like this concept of "energy accounts" is going to be difficult for them.  Or maybe it's just difficult for me.  Anyway, I wanted to try to drive home the idea more before they have to apply it to a graph.

In a perfect world, I would have done the Icy Hot Lab over two days.  In that perfect world, we would have discussed and planned part 1 as a class.  We would have white-boarded and discussed our results from part 1 before going on to part 2.  But... that couldn't happen.  Monday, I have to proctor a state writing assessment.  Tuesday is when the juniors take the ACT.  So we crammed everything into today and will discuss results whenever we can.

I had to make some changes to this lab.  First, we used hot plates instead of ring stands/bunsen burners.  Our ring stands are pretty chintzy and our iron rings are ridiculously tiny-- supporting a beaker of boiling water over a bunsen burner was not going to happen safely.

The world's worst hot plates.  The entire casing gets hotter than the actual burner.

Secondly-- no Vernier.  :(  This is one case where I truly would have preferred collecting data and graphing with Vernier if it were available.  Instead, I had my students manually record the temperature every 15 seconds with digital thermometers.  I have no idea of 15 seconds was an appropriate time interval-- looking over the data, I'm not sure if we're going to see good curves.

There was no shortage of "teacher mistakes" with this lab.  For example, I forgot to have them make a hypothesis of how their curves will look.  Big oops!  I was just so worried we wouldn't have enough time to execute the lab that I completely forgot.  I also forgot to demonstrate how to take accurate temperature readings with my first class of the day.  I realized a couple minutes into the experiment that most groups were just letting the thermometer sit against the bottom of the beaker, giving them artificially high temperatures right from the start.  I was able to prevent this in my later class periods.

Another problem I noticed early in the day was students trying to fudge data-- they had an idea of what they thought should happen, so they kept trying to make the data match that idea (which is going to totally botch their curves).  I didn't get as much time to address this teachable moment as I would have liked, but I did make a point to tell all students to record what the data says even if they believe it may be incorrect.

When it came to the freezing of lauric acid part, the teacher mistakes were still in full force.  Again, I forgot to tell my students in my first class the importance of keeping the lauric acid hot before you begin.  Most of them grabbed the sample and let it sit a few minutes while they got organized.  Their samples were well under 50C when they began recording temperatures, giving very linear data.  By the time I noticed this, the groups were so far into the data recording that there wasn't time to start over.

Test tube of lauric acid cooling and freezing as it sits in a beaker of cold tap water

I just hope we get usable data out of this experiment.  I don't want to create/reinforce existing misconceptions.  Also, students will be writing their first lab report over this lab and I don't want it to be harder than it needs to be.  If the data is erratic, they are going to struggle with their conclusions and questions.

Did someone order a mid-winter vacation?

We were out for, count 'em, ELEVEN days in a row thanks to inclement weather.  For President's Day weekend, the students were supposed to have a 4 day weekend.  Staff was supposed to have an inservice day and parent/teacher conferences on Monday and Tuesday.  What we had instead was a huge snow and ice storm on Sunday night.  The storm was followed by a blast of unseasonably cold arctic air which stayed in place for over a week.  Here in the south, we don't have the resources to remove snow-- it usually just melts the same day.  So everyone was just forced to stay inside and wait for it to melt... and we kept waiting... and waiting... and waiting...

Eleven days later, we're back in school.  On Friday the 13th, students took their Unit 2 test.  I barely made any alterations to the test in the curriculum-- I think I added 2 EOC practice questions, a handful of temp and pressure conversions, and made one of the more difficult problems extra credit.  Results were much better than the Unit 1 test.  Lots of As and Bs and Cs and only a few Fs in each class (although I still have a boatload of students to make it up who were absent last Friday).  I actually had a student tell me today that PVTn problems are her favorite thing she has EVER done in science class.  Seriously?  Even I think that's a little sad.  But hey, I'm happy to finally have some level of engagement in chemistry.

Students have interruptions galore over the next few days, plus there's more snow in the forecast.  As a result, I'm greatly abbreviating Unit 3.  My goals are for the students to understand phase changes and heating/cooling curves, and I'd like to attempt the energy bar charts and a few heat problems, but only if there is time.  Today there was a lot of catch up to do after the long break, so we eased in with the Eureka video on Heat & Temperature and did the Energy & Kinetic Molecular Theory reading/study guide.  Tomorrow-- Icy Hot!

Unit 2 Reflections: Worksheet 3 PVTn Problems

My students... bless their hearts... grr...

Graffiti is beginning to appear on the back of my white boards.  It's mostly your typical, teenage stuff- doodles, smiley faces, although one board had a curse word in marker.  I did not have this problem AT ALL last semester.  I am NOT okay with this.  I'm 99% sure it is happening during our board meetings when they are holding up their boards, and specifically, I'm also 99% sure it's happening in my last class of the day.  In that class, I already catch them trying to hide behind their boards and text, read, sleep...  Instead of addressing the class about the graffiti, I think I'm just going to say from here on out the students need to prop them up at the front of the room.  On a related note, at our workshop, one experienced modeler mentioned that he has hooks hanging from his ceiling to hang the white boards-- if I ever get my own classroom, I'd love to do that.

Anyway- PVTn problems.  I mentioned in my last post, I had zero interest in deploying the "factor" arrow method for solving these problems.  Maybe someday I will change my thinking, but I personally do not see how that is a benefit for them.  Especially not when my students are given the combined gas law on their EOC equation sheet.

I do think the PTVn charts are helpful.  It keeps the students organized, and drawing an arrow for the "effect" helps maintain a connection between their conceptual understanding of particles and the math.

A sample of the PTVn charts on the first page of worksheet 3

I do not think worksheet 3 alone was enough practice and assessment.  In a perfect world, we would have more time to spend on this.  I planned poorly-- I planned for the test tomorrow, thinking we'd complete and check worksheet 3 yesterday.  We didn't check worksheet 3 until today, which cut into out review time.  But we have a 4 day weekend for President's Day/in-service, so delaying the test any longer won't be to our advantage.

Also, I think worksheet 3 is a *bit* overwhelming for low-level standard chemistry students.  There were too many different pressure units right off the bat, including some "minor" conversions.  And by problem #3, they are throwing the STP in there.  I would have liked to have built the students' confidence up with some more straight forward problems before I start switching units or worrying about STP.  If I have such low-performing students next year, I think I will add several easier problems at the beginning.  Also, the problems are boring as all get out.  I'd like to put some "real life" spin on these calculations.

But... after the kid's initial FREAK OUT at having to do some big time algebra with lots of different variables, they didn't seem to have an issue with solving the problems.  I'm curious to see how they handle them on the test tomorrow.

Unit 2 Reflections: PVTn Labs

It's no fail-- my students always surprise me.  Sometimes for the better, sometimes for the worse...

I was having some trepidation about how seriously I should pursue calculating the pressure in a manometer flask like so:

It's not a state standard, so I was going to play it by ear as the students completed Worksheet 2.  If they seemed to understand the concept quickly, I'd have them do those problems.  If not, I wasn't going to fight the battle.  Go figure, they mastered the concept in about 30 seconds.

Overall, they did really well with Worksheet 2.  I would say 85% of the class was even successful at the pressure unit conversions at the end with minimal help from me, and I didn't even tell them it was coming.  Granted a good portion of my students still freeze up like a deer in headlights when they see a conversion, but they can do it with some goading.

We ended yesterday with a Boyles Law lab.  The AMTA lesson plans have students performing 3 labs with Vernier equipment:  P & V, P & n, and P & T.  We don't have Vernier equipment at my school, however I personally have a single LabQuest and probes of my own.  I have mixed feelings about having students do too many Vernier labs, regardless of having the equipment or not.  I feel the students often are intimated by the equipment and software, which causes them to miss the entire point of the lab.  At the same time, I've watched many college students continue to struggle with the Vernier labs.  It would be nice to give my students the exposure now so they're more comfortable with Vernier in college.  I don't think there is a "best" answer when it comes to using Vernier with standard high school chemistry students.

Anyways...

My compromise was for students to do a simple Boyles Law lab using pipets and textbooks that I found on Flinn's website:




Then for Avogadro's and Gay-Lussac's Laws, my plan was to use the Vernier equipment and demonstrate the lab the students were supposed to do from the curriculum.

The Boyles Law lab went pretty well-- it was quick and straight forward.  My first two classes of the day figured out the relationship easily for the most part. Most of their boards looked something like this:

By the end of the day, I found there were more and more student procedural mistakes.  The most common was measuring the length of the water instead of the air, giving them an incorrect graph (this one was doubly incorrect):

I was bummed about their verbal conclusion.  And confused about their particle diagram.

The mathematical expression was really hard for them on this one.  I've found here most students just don't understand inverse relationships.  I showed them the concept of P=1/V, but I'm not sure how many took anything away from the discussion.

The Vernier demos were a huge flop.  The kids were bored to tears.  They didn't understand what I was doing, they just blindly copied the graphs on the screen into their lab notebook.  Seriously, there was zero advantage to pulling out the Vernier equipment for a demonstration in this instance.  I might as well have just talked at them for half the period.

What was most helpful, again, was the PHET simulation.

We also did a KMT reading out of the textbook, or tried to.  I wanted them to read thoroughly and write, but we only had about 10 minutes left at the end of the class to do the activity.  It became more of a "scan for the answer" activity, which I hate.

Tomorrow we will tackle PVTn problems using the combined gas law.  While I plan on using the PVTn charts, I'm not teaching the factor/train-track method they showed us in our modeling workshop.  Not happening.  I'd rather the students be able to plug and chug into the equation that they will receive on the back of their periodic table when they take the EOC.

Unit 2 Reflections: Pressure, Straws, and Blow Up A Kid

I'm not sure if today was the best use of our time.  I don't feel like my students have any better "mental image" of pressure after the two activities.

Part of this may be my own misconceptions, but I'm not exactly sure how playing with a drinking straw is a good introduction to the idea of pressure.  The synopsis:  lab groups were given straws and a cup of water to play with and told to develop and white board a "trick" they can do.  Our workshop leader suggested doing this to engage them.  95% of the groups did the putting your finger over the top of the straw trick.  We didn't have any good discussion on suction, except that we are pulling air particles out, which causes other particles to take its place.  We kind of wasted 15 minutes of class time playing with no "ah ha"  moments.

Then we did the "blow up a kid" demo.  For this, you need a trash bag, sealed with duct tape, with 4 straws inserted into the corners:

I thought this would be a huge hit.  It wasn't.  Surprisingly, no one wanted to be "blown up."  No one wanted to blow on the straws.  The brave souls who did volunteer to blow it up told me the air tasted like other people's bad breath (ick).  And most importantly, I don't think it helped our mental picture of pressure any.  Probably half of my students were having a hard time visualizing that it was the air particles colliding with the bag that provided the force to lift the kid off the table.

The PHET Interactive Simulations helped the students better understand how particles cause pressure.  I strongly recommend using it as a visual at very least.

I put some notes/discussion questions into PowerPoint form for pressure, since there were a lot of particulars with the units that the students are supposed to take away from the discussion.  In the PowerPoint, I defined pressure, introduced the 4 common units (psi, Pa, mmHg, and atm) and talked about hand water pumps and Torricelli.  I also had some slides on barometers and manometers.

The goal was for Worksheet 2- Measuring Pressure to be homework, but they weren't even remotely ready to attempt those problems on their own.  Now I'm kind of wanting to skip them myself-- we're so far behind... I'm not sure if calculating pressure in a manometer is the best use of our time and their brain cells.  We might do it as a class on Monday, although then I won't get a good assessment out of it.

Monday, my goal is to do a modified Boyle's Law lab using clamped pipets and textbooks.  We do not have Vernier equipment at my school.  I have one set that was given to me as part of my modeling workshop, so I plan on breaking that out for a demo for Charles' Law and Avogadro's Law.

I really hope I can recoup some lost time during Unit 3-- I plan on slashing a lot of Unit 3's material.  I really just want students to understand the concept of phase change diagrams, heating and cooling curves, and some basic specific heat problems.  I'm hoping we can do that in 5 days maximum.

Unit 2 Reflections: Diffusion Demos

I feel I'm finally making some progress with my students.  I've said this before-- hopefully I won't end up eating crow this time.  This week started with a state writing assessment that interrupted Monday's classes:  I only saw about half of my students on Monday while the other half tested.  Kudos to my school, though-- I really like how they implemented it this year as opposed to last year.  We only had a single day of interruption, as opposed to an entire week.

The interruption was not a bad thing.  It allowed me to work one on one with a number of students who really needed help, but aren't dedicated enough to ever come to tutoring after school.  I feel like I have more of the class on the same page now.

This unit, I also have decided to reduce lab groups from groups of 4 to groups of 3.  The leaders of our modeling workshop were big proponents for groups of 4.  It also fits really well with the "Lab Roles" sheet they gave us.  However, I think with standard-level students, groups of 3 are much more efficient.  When there are 4 students in a group, there are too many opportunities for the less motivated students to zone out or get off task, even when they are supposed to have a role.  I used groups of 3 with my standard biology class last semester because of the small class size and just told the students that the lab manager is now also responsible for the recorder's role.

On Tuesday, we began Unit 2 ironically by completing "The Model So Far..." for Unit 1.  Students then read a brief article on Democritus' atomic theory and wrote a short response comparing our model to his.  The consensus:  we are thinking like Democritus at this time, but we also know from prior knowledge that Democritus wasn't completely correct.  I gave a little speech about why we are doing this:  since we can't see particles, we need to be able to paint a good mental picture of what's happening with these particles.  And yeah, a lot of this stuff seems basic, but if we have a good model in our heads, we can add to this model just like scientists' added to Democritus' original model.

I am learning that with my current group of students, I have to be extremely clear on what we are doing.  They are literal to a fault and do not "go with the flow" well.  So if they don't 100% understand an activity or a demo before we begin, they shut down.  I've been using a lot of straight forward guiding questions before an activity.

I had them create a page in their lab notebooks that said "Unit 2- Energy & States of Matter" and explained we would be looking at how energy affects the states of matter.  Then I first told them we would be observing how particles move in the gas state.  We talked about what odors are and how our sense of smell works.  I then had them set up a page for the demonstration observation of the movement of Axe Body Spray through the classroom (I didn't have strong enough perfume).  I had them write a guiding question:  How do particles move through gases?

The demo is straight forward:  spray a puff of strong-smelling stuff in the center of the room and have students raise their hand when they smell it.  Also, have them record the order in which people smelled it in their lab notebooks.

After the demo was complete, in new lab groups, I told them to story board all particles involved in the demonstration from the moment I sprayed the Axe until I said stop.  The results were interesting.

Many of them forgot the air, or didn't think it played a role:

Others seemed to just think it was co-existing in the room, but not really doing anything:

And then some groups got extremely creative:

They explained that the particles joined together and started moving all around the room

Misconceptions galore!!!  This is one thing I love about the modeling curriculum.  Diffusion seems like such a basic concept that I've always thought my students understood, but in reality, they had zero clue that the air in the room was a factor.

I led them back on track by giving them the loose analogy of a pool table:

I can rack my billiard balls into a triangle, but what causes them to break?  How do the balls move when the cue ball hits the triangle?  What if I racked my balls, but decided not to play pool today and never shot my cue ball, where would the balls be tomorrow?

From that, they were able to understand that the room air particles were crashing into the Axe particles, causing them to move in different directions than they would on their own and spread throughout the room.  I then told them we call this "diffusion."

I reinforced the idea with THIS simulation on Kinetic Molecular Theory, which shows a red particle getting bounced around in a sea of moving blue particles.  We used this simulation to define "diffusion" as a class.  All the classes came up with something the along the lines of particles being spread out due to collisions between particles.

Next, it was on to how particles move in liquids.  For this, we did a simple demo of food coloring in hot and cold water.  You'd think students would have seen this a million times by their junior year, yet some still were surprised.

This time, many of the story boards were more on target:

  But there were still some interesting interpretations:

Say what?!?

We used the above board (and similar boards in other classes) as a teachable moment about making sure our particles represent what we think is happening, but also make sense based on what we see.  I try really hard not to make groups feel dejected, so I am constantly saying we do this on white boards so we can make silly little mistakes now and erase them easily, instead of making the mistakes on the test.  I had other groups pick out things on this white board that someone might misinterpret-- for example, the hot water particles weren't hovering at the beginning of the demo... or that you can't create matter from nothing...

We then watched the first three Eureka videos on Heat & Temperature.   I found them on YouTube.   After our modeling workshop this summer, I honestly did not anticipate using the Eureka videos.  I hated the idea of showing students something so dated.  But... they do a really good job at making sure there are no gaps in their mental image of particles in solids, liquids, and gases.  I had them answer eight straight forward questions on the videos in their lab notebooks, just to make sure we got some information from them.

So far, this unit seems to be going slowly, but MUCH better than Unit 1!!!