Physics & Physical Science Demos, Labs, & Projects for High School Teachers

Posts Tagged ‘Problem Solving

Last year, the course was actually called Robotics and Astronomy, or Robostronomy for short.  The intent was half-year of each.  The result was more like three weeks of astronomy and robotics all year-long.  Don’t get me wrong, I love astronomy.  It’s just, well, Robots took over the Earth.  Between the great things we could do with the MindStorm, and then the SeaPerch competition, we were all robots, all the time.  This year we are adding the First Tech Challenge.  Yep, Robots have taken over the Earth, and it looks like they landed in my classroom.

The goal here is STEM, that’s what opened the door for the robot invasion in the first place.  Clearly missing from our program these days is what we called in the old days, ‘drafting.’  Drafting isn’t done on a board with a T-square anymore, but you all know that.  Today, 3D mechanical Computer Aided Design (CAD) is available for free from Google (Sketch-up), and from a number of companies who cater to the high-end.  I actually know this industry well, I spent 25 years in the CAD/CAM/CAE industry (M for manufacturing, E for Engineering, meaning simulation).

So with some guidance from some friends at Drexel University, and a little research on my own, I decide to go with SolidWorks software.  All of the vendors have aggressively priced programs for the educational market, I think we are paying just $1000 for a 10-seat license.  What makes this software connect to the students is what we spit out of it.  The school invested in a 3D printer, specifically uPrint Plus from Dimension.

If you have never seen one of these, think Star Trek Replicator.  The replicator creates parts from ABS+ plastic directly from the output of the 3D CAD.  How better to teach engineering principles than to give the students a design challenge, have them work through designs and then fabricate it in the printer.  Here is a great video from a customer talking about how they use a 3D printer in their engineering design work.

My new printer is due here any day and I’m pumped up.  Yep, geek boy has a new toy.  Tea, Earl Grey, Hot!

physicsI’ve always found it challenging to get students to draw the problems.  I don’t understand their reluctance, I can’t imagine trying to keep the facts in my head, yet so many of them do just that.  The result is that they miss details and make mistakes.

Today I saw a simple problem that I thought I would use as an introduction to drawing problems.  The simple word problem says:

[Updated as used in class] There is a triangularly shaped park with trees along the edge.  There is a tree at each vertex.  Each side has five trees.  How many trees are there all together?

Very simple problem if you just draw it.  The answer is not 15.

I just got this idea in the shower this morning.  Here’s the basic lesson:

  • Divide the class into groups.  Give each group a complete but non-working flashlight.
  • Ask them to look at the flashlight, but not take it apart.  They are to predict why it isn’t working and propose a solution.  They need to come up with a test to show their prediction is correct.
  • Once documented, they can take the flashlight apart and attempt repairs.
  • Each time they reassemble the flashlight and it doesn’t work, they need to stop and come up with a new written plan.
  • The group must document each step as they try to determine what is wrong with their flashlight.

Since these are very simple devices, they can be set up as follows:

  • One or more dead batteries
  • Tape over battery terminal
  • Batteries installed incorrectly (positives together)
  • Dead bulb (see update below)
  • Switch or broken circuit in flashlight

I would probably set each flashlight up with at least two failures so that the exercise is not over in a minute.  For instance, if I installed the batteries incorrectly, I would also make sure that one of them is dead.

There are two ways they can problem solve.  They can share parts with other groups to make the flashlights work or there can be a pile of batteries, bulbs, and bodies to use.  I’m also not sure if I want to have meters available.  I may have them available but only if someone thinks to ask for one.

I’m not sure how I want to conclude the lesson.  I would probably go into a class discussion of how they developed their plan and made sure the test did what it was supposed to do.

This looks like it’s going to be fun to watch.  I need ideas for wrapping it up.

Update… We did this lab today (9/11/08)

I wrote a lab procedure for this:  Flashlight Lab.  There were only a couple little changes.  I used clear plastic between the bulb and the bulb holder.  It made the bulb look perfectly normal, but it formed a nice invisible insulator that served to fool them for quite a while.  For the switch, I put clear tape over the contact from the switch.  Some of them found that though, it was hard to disguise and it stood out.

I didn’t let the students share information between groups.  I told them I didn’t have spare batteries, so they had to come up with a way to test them.  If they were clever enough to ask, I let them use a multimeter or spare parts from other flashlights.  I didn’t show them how to use the meter, but I did set it up properly.  They figured it out on their own, which impressed me.  I was hoping they would think of swapping parts with their neighbor, but they didn’t.

This lesson served two purposes: it demonstrated the scientific method since they had to cycle through the hypothesis-test-results process several times until they figured out everything that was wrong.  The lab also served as a lesson in following directions.  One of the groups did exactly what they were to told not to do and took everything apart and got it working in a minute.  They had no documentation, hypothesis, or controls.  They couldn’t tell me the three problems with their flashlight, their experiment was worthless.  I told them that they failed the lab and they also showed me I can’t trust them with chemicals and fire in the lab if I can’t trust them with a flashlight.  Hopefully that made an impression.

This experiment was done in my 12th grade Physical Science class and the overall response was positive.  The kids liked the hands-on challenge and were impressed at how devious I was at sabotaging the flashlight.  I think this is definitely worth doing.  Let me know what you change and improve.

What’s New in 2013/2014?

Every year brings a change, this one is no exception.

I will be picking up the sophomore honors Algebra II class to keep them separate from the juniors. This should help accelerate them and put them on a stronger track towards Calculus. Looks like there will be only one section each of Physics and Calculus, but still two of Robotics & Engineering.

Hot topics this year are going to be the Common-Core Standards, Standards-Based Grading (SBG), improving AP Calculus scores, and somehow adding Python, maybe as a club.

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