Unit 4 Reflections: Worksheet 1 and Electrolysis of Water

Going by the modeling "book" is not working for me lately.

Friday: I expected pure substances vs. mixtures to be a review for my students, especially after the feedback I was receiving in our post-lab discussion.  The topics are covered heavily in physical science. The students usually blow right through it in years past.  I thought it would be a great chance to squeeze in some much needed textbook reading/writing practice, with it being a familiar topic that is not all that difficult to grasp from reading.

Um... no.  That's not how it went with these students.

Friday, in class, they were assigned to read the (very short) unit out of the textbook on classification of matter.  They were then to write me a paragraph classifying the stuff we saw in the lab (salt, sand, iron, salt/sand/iron together, water, sulfur, iron, iron sulfide) as a pure substance or a mixture using vocabulary they read in the text.  I figured after they read about the topic, we'd jump right into Worksheet 1 on Monday.

What they actually did instead of reading-- sit with the book in front of them without flipping a page, then turned in a list of garbage that showed they didn't even as much look at the headings on the pages.  Not cool.  I know it was Friday, but COME ON.

So, I got to spend all of Monday reteaching what they didn't read in the book.  I did it in a PowerPoint that I've used in the past, then finally gave them Woksheet 1.

I've never understood why this is so hard for students:

I used to assign a similar worksheet in years past and my students went into panic mode when they saw it.  After my Modeling Workshop, it occurred to me that I was assuming that students had a conceptual picture of particles when it was something I truly never taught.  This year, since we have been explicitly working in conceptual "particle" mode all year, I didn't anticipate it being nearly as panic inducing.  Wrong again.  *head desk*

So we wasted more time today slooooowly correcting the very wrong answers on Worksheet 1 until it finally seemed like my students had some idea of the difference between elements, compounds, and mixtures.

Onward ho-- next we were supposed to start building towards the Law of Definite Proportions with a demonstration using a Hoffman Apparatus.  My Modeling Workshop was generous enough to provide us all with our very own Hoffman Apparatus!  Unfortunately, they didn't give us a power source.  Never fear, they told us, you can just use a 6V or 9V battery.  Ha.  Hahaha.  Ha. Of course, I procrastinated until the last minute to try this idea and found that while a battery will cause some decomposition, I could not get the reaction to go nearly fast enough to be visually impressive.  Maybe it was just me.

I needed a backup plan.  My first thought was to do the 9V battery/pencil lead electrolysis of water-- but a single set up is way too small for an effective demo.  Plus, I really wanted them to see that it was twice as much hydrogen than oxygen, and actually prove it was hydrogen/oxygen and not just bubbles.

Thanks to Google and YouTube, at the 11th hour I was able to rig up some of these setups using materials I had on hand:

Small plastic container with two push pins through the bottom, 2 test tubes, a 9V battery, and a solution of water with a small amount of sodium biocarbonate

The containers were a little cumbersome to manipulate, but the setup worked well overall.  Between weak batteries and time constraints, we didn't see a perfect 2:1 ratio, but the students clearly saw more gas being formed on the cathode side than on the anode side.  I was able to come around with a flaming splint and demonstrate the hydrogen "pop" to each group.  There wasn't quite enough oxygen to re-ignite a hot splint, but it was enough to at least make the flame visually grow.  We discussed how water vapor would not cause a flame to grow or pop-- too much water vapor may even extinguish a flame.  We also discussed that the container did not feel hot enough to be boiling, so it couldn't be "boiling" water.

I told them that scientists have found that a compound of a substance always has the same ratio of elements.  Water is always 2H:1O.  We then hypothesized the ratios of elements in other familiar compounds, like sodium chloride and glucose.

We were going to watch "Gases and How They Combine," as suggested by the lesson plan.  I watched the video myself on YouTube and it is BORING and dated.  While the demonstrations and explanations are great, I don't see my students paying enough attention to get anything out of it.  I think we'll jump right into Worksheet 2 tomorrow... then on to Dalton's Playhouse.

Despite being dreadfully far behind and feeling like 50% of my students are shut down... I do hope that by the time we get to balancing equations, it should be a non-issue.  That's basically all they are doing in Worksheet 2.

Unit 4 Reflections: Separating A Mixture

I've had to shake things up a lot.  Last week, we had two more snow days and two days where I lost my students to standardized testing.  I basically said to heck with the rest of Unit 3.  We didn't do any of the specific heat calculations.  We quizzed on the types of energy, energy bar charts, heating/cooling curves, and phase diagrams (my addition) and called it a loss.

I'm also shaking up Unit 4 a bit.  For starters, it begins with demos and discussion.  Unless I'm blowing something up, my unmotivated, under engaged juniors don't give a darn about demos.  And I've been struggling all year to get my students to buy in to group discussion-- it does not happen easily.  I truly needed to get them in the lab.  I fell back on the old "Separation of a Mixture" lab, an activity that I usually do at the beginning of the year to introduce them to the concept of experimental design and properties and mixtures.

We started Unit 4 by defining properties, then differentiating between physical and chemical properties.  I then gave them a sample of salt, sand, and iron filings and asked them to develop a plan, using their properties, to separate the three substances.  I offered them a list of available materials to help them out.  Considering I rushed them a bit on their experimental design process, they didn't do too terribly.

Overall, I was really impressed with my student's white boards with the exception of their particle diagrams.  I was very specific for the verbal this time:  I asked them to answer the question, "Why were we able to separate the three substances?"  I was very specific for their math as well, and told them to show me how to calculate the percent composition of the mixture.  I left the graphing and particle diagrams completely open ended, asking them to do what they felt was appropriate.

Most boards looked like this:

Strong answers to the questions, good math, appropriate method of graphing data, dreadful particle diagrams (WTF?), and an overall inability to spell the word "separating."

We addressed the particle diagram issue today.  I hope they got the point-- everyone was utterly braindead today.

Unfortunately, many of my lazy students have caught on that I don't actually grade whiteboards.  So, several groups produced garbage like this:

At least they figured out how to calculate percent composition...

Um... yeah.

I also performed the demonstration of heating iron and sulfur.  This is a demo I had never done before.  I could not get it to react with a hot stirring rod or hot splint.  I ended up using a ring stand, a heavy watch glass, and a bunsen burner.  The odor is horrific and the ignition was not all that impressive to the students.  I think the bunsen burner flame confused them- they just thought it was flammable even though I made a point of showing how far away the flame was from the iron ring.  But, they were able to see that we got a substance with different properties from either of the original two substances.  We left off with a textbook reading about pure substances vs. mixtures.

We'll do worksheet 1 on Monday.  I haven't shown them fractional distillation equipment (we don't even own any), so I suppose I should do that first!  Youtube here we come...

On a side note, my students had to take a district wide benchmark test today.  It was created with traditional pacing in mind, so many of the topics we have not covered.  When I flipped through the test, I figured there were about 11 out of 30 questions that my students should be capable of answering.  I was at least encouraged to see that my students mostly got those 11 questions correct.

Unit 4 Wrap Up

Remnants of our photosynthesis lab

You know that feeling when everything hits the fan?  That's been my past couple weeks.

I thought Cellular Respiration and Photosynthesis went well.  My test results from last week said otherwise.  Looking back, Unit 4 was WAY too much material and way too diverse of material.  I was aware of this while I was teaching, but I didn't realize quite how significantly it impacted my students until the test.  Grades were still good, but class averages were lower than usual.

In my darling standard biology class, the 50:50 split was worse than ever.  Half the class had high As, two Cs, and the remaining students failed and failed badly.  For those students who failed, they temporarily lost their lab privileges and in lieu of lab completed an open notes re-test.  The strategy seemed to help, re-test grades were much improved, and I was able to work one on one with many of them while the other students were working on a dialysis tubing lab.  I realized two things working with the students individually:  1) just how overwhelming this unit was, and 2) the average sophomore in high school knows NOTHING about plants.  I mean nothing at all.  Multiple students said that my class was the first time that had EVER heard that plants make their own food.  I'm not sure I've ever encountered that before... but without any prior knowledge to help make connections, the process of "photosynthesis" was a billion times harder for them.  Who woulda thunk it.

In the meantime, we've started Unit 5 The Cell.  I've made some modifications due to time.  We did an intro to the microscope and looked at plant and cheek cells.  Then we did some diffusion/osmosis experiments, including perfume in air, food coloring in water, and glucose/starch in dialysis tubing.

Out of all my classes, only ONE group included "air" particles in their diagram.  Obviously this wasn't the group.

Dialysis tubing with glucose/starch solution placed in a beaker of DI water and Lugol's Iodine.  Fun fact- glucose didn't diffuse through the tubing as it should have this time around. I inadvertently reinforced a misconception in all my students' minds.

Not the strongest conclusion ever... 

We also set up a "rubber egg" osmosis lab instead of the potato lab included in the teacher notes.  Meh, I wasn't feeling the potato set up.

We have, count 'em, less than FIVE more weeks to get through:  transcription/translation/protein synthesis, enzymes, mitosis, meiosis, and all of genetics.  Ouch.  Let the panic attack begin.

Unit 4 Reflections: Cellular Respiration Continued

Cellular Respiration-- not one of the most interesting things we get to teach as biology teachers.  I mean honestly, raise your hand if you actually care about the Krebs Cycle?  I sure don't.  And I've never totally understood why or how it's important for the state to test students on whether more ATP is produced in Glycolysis or Oxidative Phosphorylation.  But I digress...

We held our board meetings on yesterday's activities.  Here's how I set it up:

Yesterday, I had written a generic definition of "cellular respiration" on the board that they copied down between activities.  I didn't talk about it at all, I just told them that they were modeling "cellular respiration" with the ball and stick models.

Today, I asked them to refer back to that definition and create a white board with a verbal, mathematical, and diagram explanation of that definition of cellular respiration using evidence from the two lab activities.  They were confused and stumped, but surprisingly game and receptive to the challenge.

Prior to WBing, we had recapped about the "ingredients" in each of the balloons, and even hypothesized a little about each of their role in inflation of the balloon.  They had some really interesting theories they were all sure of-- the warm water caused the molecules in the balloon to move faster, causing expansion of the balloon.  The warm water dissolved the sugar faster so it could "react" with the yeast.  The yeast was a catalyst.  The yeast produced oxygen.  I just kept telling everyone those were interesting theories.

Most groups used the chemical equation for mathematical (I kinda tipped them off on that), and diagrams of the balloons or models were easy enough-- but they were stumped on the verbal.

In each class, I spend a lot of time with about 50% of the groups firing questions at them, and basically ignored the other groups.  I tried to focus on the "weaker" and more uncertain groups.  They all had the same questions:  "We don't know what you want us to do.  These labs had nothing to do with each other."

In my rapid firing, we focused on the glucose and the chemical equation.  Glucose was one of the reactants in the model of cellular respiration.  Was glucose involved in the balloon lab at all?  (Yes, it could be derived from the sugar)  Was anything else in the chemical equation also found in the balloons?  Where did the oxygen come from?  What evidence did you have CO2 may have been produced?  Does it seem plausible that this reaction could have happened in the balloon?  So if I leave sugar sitting on the counter, it will turn in to CO2 and water, right?  (Umm... no...)  Then why did the balloon inflate?  What else was in the balloon?  Re-read that definition-- why did we add the yeast?  What did we discuss about yeast earlier?

And then about that time, each group had the most rewarding OH MY GOD I GET IT light bulb moments.  :) :) :) :)

My only regret is that these groups were SO excited they "got it" and while many of their peers still didn't... and they WANTED to blurt it out in the board meetings.  The groups I spent time with were waving their hands in the air the entire board meeting, wanting to talk... and I reeeeeally wanted to let them show off their new found knowledge.  But... I also wanted everyone else to have that same epiphany.

We then did a terribly boring textbook "active reading" session about ATP.  Great way to cap that good discussion, huh?  But there was a reason.  On Monday, we had a district teacher inservice with a speaker who I will not name.  He was not one of the better educational speakers I have ever heard.  While he made some good points, overall I thought he was extremely antiquated and out of touch with today's students and schools.  His big emphasis was on more reading and writing-- less doing, more reading, writing, and note-taking.  Kids today aren't college prepared because they can't read textbooks and they can't write papers (I do agree with that part).  One of his criticisms of science teachers was that we "do" too much and pride ourselves on not even using a textbook (um, guilty).  I disagree with him that you should only read and write about science, but I do think I am doing my students a disservice if they never have to trudge through a science textbook at least a few times.  While we do read in class, our reading is usually article-based.  The speaker gave me a good reminder to step it up with the textbooks.  Reading about ATP was a perfect opportunity-- I can think of no topic more dull to practice reading dull stuff.

Each student received a photocopy of the 4 pages out of the text on ATP and highlighters.  We read the first few paragraphs together and discussed how to identify the important points... then I set them free with a guiding question (what provides energy for the cell) and told them to keep highlighting what seemed important.  Afterwards, they were to write a paragraph reflection of the reading that answered the guiding question.  We discussed our paragraphs afterwards, which was extremely insightful.  While many students did fine and wrote great summaries, here is a direct quote from a bright honors student with a 98 class average:  "I didn't understand a single thing I read."  Hmmm.  While I don't think we will be reading the textbook every day, I definitely do think I need to throw it in more frequently.

Unit 4 Reflections: Macromolecules and Cellular Respiration

...and we're back from our lovely 10 day fall break today.  And jumped right in with cellular respiration.

I've had to add a lot to unit 4.  Not only did I toss in all the ecology standards, but I also needed to cover the biological macromolecules in more depth than the AMTA lesson plan suggested.

The AMTA lesson plan has students researching proteins, carbohydrates, and lipids on their own with a few guiding questions, then jumping in to comparative dissections.  My state EOC exam tests pretty darn heavily on proteins, carbohydrates, and lipids-- especially the structures and how to determine their presence in the laboratory.  Plus, our biology teachers here usually save our dissection for the last days of class after the EOC exam, since dissection and internal anatomy are not tested.  So, I ended up skipping the dissections (for now) and spending more time on the macromolecules.

Having the students research the macromolecules with guiding questions was futile.  First of all, when given the option of textbook or Google, students always go to Google.  I don't think that is necessarily a bad thing, as textbooks are becoming utilized less and less, even at the collegiate level.  But... as sophomores in high school, students can be easily led astray by misinformation online.  Especially on a topic like this, which is loaded with intimidating new vocabulary like "monosaccharide" or "polypeptide."  The whiteboard results I got, to put it simply, were really bad.  I still think it was a good activity, but I will definitely limit them to the textbook next time to avoid wasting nearly an entire class period.  Instead of dissections, we then went to the lab to practice testing for macromolecules.

Sudan IV testing for lipids

The AMTA curriculum kicks off cellular respiration with a yeast lab using Vernier Probes to measure % O2 and CO2.  The total amount of Vernier equipment my school owns:  0.  We got nothin'.  So it was back to the drawing board again.

What I decided to do was combine a yeast balloon lab with the next activity in the lesson plan, which is modeling cellular respiration with ball and stick models.  First, students created balloons with yeast and differing amounts of warm water, sugar, and air:

They measure initial diameter, set their balloons aside, while I briefly introduced them to the term "cellular respiration."  They were instructed to make a model of a glucose molecule and 6 diatomic oxygen molecules:

A glucose and a pile of O2 - not bad for students who have never taken chemistry, let alone organic chemistry. I wasn't going to split hairs on the position of the bonds in the glucose at this point. Maybe I should have.

They were then told a chemical reaction occurred between the molecules and they needed to create two new molecules.  I asked them to think about waste products, respiration, and had to prod some groups on ideas... but all of them eventually came up with CO2 and H2O.  They were then challenged to figure out how many CO2 and H2O molecules this reaction would create.  Once they were complete, they had to create an equation for cellular respiration.

Then we revisited our balloons and determined change in diameter.

We didn't get much time to discuss or create a consensus.  My plan tomorrow is to hold a board meeting with a verbal, mathematical, and diagrammatic representation of cellular respiration based on the results of the two activities.  And I guess I'll see what I get!

Unit 4-- An ecological detour

When I did my cursory review of the biology modeling curriculum before the start of the school year, I somehow neglected to notice the utter lack of ecology included.  I guess I assumed when I saw food chains/food webs that the curriculum would somehow address ecology and interdependence in that section.  Well, you know what happens when you ASS-ume...

I believe something like 18% of my state's end of course exam is on ecology and interdependence, including human effects on ecosystems, carrying capacities, and succession.  Not to mention it's its own entire section in my state standards.  And uh, none of this stuff is anywhere in the curriculum as written.

So, the past few days have been "cram everything about ecology into a few days while pretending we're just learning about food chains."  Yay.  But it fit better here than anywhere upcoming.

I keep trying to relate everything back to energy, so it kind of makes sense with the unit.

Here's the cool part:  I'm reusing some of my previous ecology materials, but with a modeling spin.  And it seems to be working decently.  For example, I gave my students a what I think is an easy handout entitled "Deer:  Predation or Starvation" which has them analyzing and graphing the data of a standard wolf reintroduction scenario.  Oh, how my students moaned and complained about this activity last year!  The had so incredibly much trouble with manipulation and graphing of the data.

But this year, even my standard students got through it relatively uneventfully.  We used it for a segue into defining the term "carrying capacity," and they got it no problem.  I threw all sorts of carrying capacity scenarios out at them, and at least 85% of the students could predict and analyze what would happen.

Succession is another topic that we went through at warp speed, but I think they just might have gotten it.  (We haven't finished it yet with my standard class, which will be the true baseline for comparison)  We spent days on succession in previous years-- looking at pictures, drawing flipbooks, reading scenarios, etc.  Last year, I remember one of my brighter students telling me succession was the hardest thing in biology.

This year, I literally just cut up succession timeline pictures and put them in baggies-- I did one bag of pond succession and one bag of forest succession.  I told them to put each baggie of pictures in order and storyboard it on their whiteboard.  We discussed our observations and what we thought was happening, and defined the terms "ecological succession" and "climax community."  Then we discussed what might have caused the succession, divided the causes into categories, and voila!  We gave the categories the names primary succession and secondary succession.  And I sent them home with a Mount Saint Helens article for homework that will hopefully embed a few more related terms in their heads.  I mean, I would have loved to have done more, but we spent maybe 30 minutes on the topic.  From the discussion, the understanding seemed as good or better as compared to the years I've spent days on the topic!

It's the small battles, I suppose.

The downside:  we are seriously behind now.  Like, majorly, will-not-get-through-all-the-curriculum, what am I going to cut behind.  The only upside is that I'm not any more behind than I was this point last year, and my students did fine on the EOC...

Unit 4 Reflections: What is Energy and Energy in an Ecosystem- A Vital Commodity

Unit 3 tests are finally graded.  I was THRILLED to see a narrowing of the "great A/F divide" in my standard class.  Grades were higher than usual on the whole, and the number of failures was cut in half.  Some progress is better than no progress!

Verbal and diagrammatic representation of the energy in the "What is Energy" Lab

Unit 4 started off with a lab:  What is Energy?  Like many of the other activities, I found it took an excessive amount of time for a concept that the students were already pretty solid on.  There were 10 stations for groups to observe.  If I do it again, I think I may reduce the number of stations in half.  I found my students were familiar enough with the concept that energy cannot be created or destroyed and that it can transfer forms.

The teacher notes recommend reading the book, "Zoom" by Istvan Banyai before jumping into the next activity.  We didn't for two reasons:  1) We are really, really, really running short on time, but more importantly 2) I ordered the book last week off Amazon and it still hasn't arrived.  Maybe next time around.  My segue was just telling the students that we would be observing energy at the ecosystem, organism, and cellular levels.

I think the Energy in an Ecosystem- A Vital Commodity was great, except for one pesky detail.  In every single class, one of the trophic levels performed "better" than it should have despite me adjusting the numbers of each organism.  In both my honors classes, for some reason the dolphins acquired more energy than the cod:

Dolphins have more energy than the cod and the shrimp!

This has been easy enough to address through discussion, but I am still worried it is reinforcing a big misconception that the top organisms have the most energy!  I was trying to wait to stop the simulation until some dolphins died, but the problem was that my shrimp and cod were dying faster than the dolphins despite sufficient numbers of plankton.  If I waited for the dolphins to die, we would have had very little data.

In my standard class, who hasn't white-boarded yet, the cod were higher than the shrimp, which may make a huge mess when we graph.  I told them we might repeat the simulation tomorrow.

So we don't have that perfect graph to tip on it's side to make a nice half of an energy pyramid, because our data is off.

In the future, I might plan to repeat this simulation a few times until we get usable data.