Straws, M&M’s, and Resources

My last lesson this week was a short one (60 min classes instead of 85) and I wanted to make it especially engaging as the week ended and spring break started.  I’ve gotten away from the practice of giving a test right before a break, partly because I’m worried that after 2-3 other tests the students might be tested out and not perform as well, and partly because that means I don’t get to enjoy my break because I have to do a lot of grading.  I decided a very kinesthetic lesson (with some written reflection) would be a good way to wrap up the week and candy only makes that better.

We started with straws to get a new lens on resistance in circuits.  Students were first asked to take a deep breath and exhale through their mouth.  Following this, the took a break and exhaled through a single straw.  Easier or more difficult?  Students all agreed that the straw made it more difficult.  They gave reasons about it being skinny or narrow.  I connected this to the narrow filament of a light bulb (we did a TPR activity around this in an earlier class) to see that it is more difficult for air to move through a narrow tube, just as it is more difficult for electrons to move through a narrow wire. 

Next, we exhaled through three straws at once.  These straws were placed side by side.  Students alternated between exhaling through one straw and three straws.  Which is easier?  Three straws allowed more room for air to leave.  There were different paths the air could take.  It was noticeably easier.  We connected this to the parallel circuit, where there are multiple paths for the electrons to travel through.  Each new straw (or resistor) reduces the difficulty (resistance).  There was a diagram on the board as a reference.  The straws were parallel to each other (assuming they didn’t get bent), and they allowed for multiple paths of air.  The light bulbs on the board were along wires that were parallel to each other and had three different paths.

Finally we had to look at a series circuit.  The three straws were connected to make one big straw.  This was more difficult than any of the previous configurations.  Students said there was more narrowness.  Some connected more straws to make it even longer.  The series circuit is more difficult for electrons to travel through.  Light bulbs are along one path of wire, one after another.  The straws make one path for air and straws are connected, one after another.  Adding more straws (resistors/light bulbs) makes it even more difficult for air (electrons) to go through.

I really liked how easy this activity was and how obvious the result was.  Every student could engage in the activity.  They now had a physical experience to connect to resistance in different configurations and added pictures of the circuits and the straw version of the circuit with some notes.  Following this, students wrote a paragraph explaining the activity and what it teaches us about circuits and current. 

After this, we did another activity with manipulatives.  Students moved M&M’s (electrons) through different circuit diagrams.  They moved in turns and counted how many M&M’s went through a light bulb each turn.  The rule: The voltage drop across the light bulb is the amount of M&M’s that move through it each turn.  After 10 turns they totaled the number of M&M’s that passed through each light bulb and compared numbers to what they knew (from previous tasks) were the relative brightnesses.  This activity was hands on, gave a reason for the brightnesses (with a model that could be applied in the futures) and helped illustrate that M&M’s (electrons) are spread out on the wire, not stored in the battery awaiting release. 

I found the straw activity in some Modeling resources that I had saved on my Dropbox.  I came up with the M&M activity on my own.  I’d recommend both for classes to continue to develop a conceptual understanding of circuits.  What I really want is a good source of great activities for exploring physics.  There is some much information on the web that it is hard to find these activities when you need them.  I shared the straws activity with some people in my fellowship, but I want more activities that are simple and very effective like this one was.  I’d love to have a bank of engaging, easy-access activities to use for all topics.


Fun with Play-Doh

The past two days we started to look at series and parallel circuits through a guided lab that uses Play-Doh instead of wires.  Play-Doh conducts electricity because of the high salt content.  Just the idea that Play-Doh can carry a current engaged many students.  Some didn’t believe it would work, others were just amazed. 

The students worked through 5 circuits, following pictures to easily make the circuit, then writing down observations on the light bulbs in the circuit.  They find that the light bulbs only light up if they bridge a gap in the Play-Doh wire (ie, there is no short).  They learn that two lights in series aren’t very bright, but are then surprised when the two lights in parallel are both bright.  Play-Doh allows shorts to easily be created by just taking another Play-Doh wire and tapping both sides of the light bulb.  This was perhaps the richest part of the experience.  Students had to reason why adding the alternative Play-Doh path turned the light off. 

Overall I really like this lab because students can work through them at their own pace easily.  Doing the task is simple, they just follow pictures.  Writing observations is simple, they just write if the light is bright, dim, or off.  Reasoning all of this is complex.  For the reasoning they need to think like a scientist.  I think the relative ease of completing the initial task helps students build momentum and confidence for the more difficult reasoning.  Also, from the other circuits work, it seems like they enjoy puzzles and wondering.  This activity is fun and they care about the answer because the lights turn on and off right in front of them without any kind of switch.  It’s almost like magic.

In particular I’m happy with the progress of one student in this activity.  I’ve had a student that shut down in all of his classes and just didn’t care about doing work, passing classes, or graduating.  He’s a bright kid and used to ask many questions.  He’s interested in science, and once taught the rest of his table the difference between a black hole and a worm hole.  Recently I haven’t been able to get him to do any work, even with the recent engineering a bridge project.  When the Play-Doh came out he was interested that it conducted electricity and helped make the circuits.  I’m hoping I can continue to engage him in this topic through these hands on, puzzle-like tasks.

Group Conctracts: Firing Group Members

I’m collaborating on a Project Based Learning unit with two other teachers in my teaching fellowship as initial exploration before doing a PBL workshop in the summer.  We’ve just started doing some work on group contracts to keep members accountable and responsible.  There are a few ideas that I love, and some that I find interesting but haven’t made my mind up about.

I love the idea of groups creating their own contracts (with support/guidance from teacher when appropriate) because I am all for students working towards personal responsibility.  I think group effective work is a good discussion to have and can be a very beneficial learning experience.  In the materials we are using, the example recommends having a total amount of points for the project that the group then distributes how they see fit.  They must unanimously agree on the distribution of points.  I really like this idea because I’ve personally been in groups where I end up doing all the work because I care about my grade when others do not.  I wonder though, what happens when students don’t agree. 

I also like the idea of group members defining roles at the start of the project.  One worry though, is will the roles make them work at different times within the sequence of the project.  Will the result be more like a relay race, rather then a unit working together throughout the duration of the project?

I’m interested most in the concept of firing group members.  If a member of a group is not pulling their weight, it makes sense that they should not get credit for other students’ work.  This could also save the issue of not reaching an agreement about points distribution.  However, what happens when a member is fired? I worry it might be especially difficult to engage a student who is kicked out of a group and now works alone.  Does this option set students up for failure or does it help make sure they don’t get pushed through the course by their peers without any personal contribution?

Guiding Student Discussion

The current work with my fellowship involves looking at ways to foster richer in class discussions that guide students towards accepted scientific understandings.  We are reading a book called 5 Practices for Orchestrating Productive Task-Based Discussions in Science and I find the ideas very exciting.  The main point is to plan and facilitate student discussions that are selected and sequenced towards important understandings, rather than having everyone just share what they did.  I’m still working through the book, but I really like the idea.

Yesterday we started circuits in my physics classes and for the first couple classes we had a discovery based portion of class followed by a mini-lecture that referenced the discovery work and organized main ideas.  In my first two classes I felt like the mini-lecture dragged on.  It wasn’t long (about 15 min with a short Think/Pair/Share around the 10 min mark) but the energy was low and it didn’t feel engaging.  For my last class I decided to try to use the discovery portion of the class to generate notes as we went.  This is not at all what the 5 Practices recommends (there is considerable planning to increase effectiveness) but I just needed to try something different.  It worked pretty well and I reflected and re-sequenced some things for my classes today.

Today my classes work much better and I really enjoyed talking with students in small group discussions and then calling back on them later in my determined order.  My first class today was also my one Formal Observation for the year (trying something completely new was a bit of a gamble here) and it was great.  My principal happily told one of the Education Specialists about how a student who has very few examples of productive behavior and contribution to the class spoke on point and added to our discussion.  This led to my biggest takeaway, which was how effective this practice was at differentiating and pulling in students with lower than average confidence. 

Overall I’m amazed at how much more engages students were today.  While they aren’t that engaged when someone else is presenting (how do we get students to want to listen to each other?) they has their moments of engagement in the topic and explored with the mind of a scientist.  I’m excited to finish the book and actually plan a lesson with this practice in mind, rather than just wing it out of necessity.