EARCOS 2009 - Kotakinibulu

EARCOS 2009 in Kotakinibulu has been phenomenal. Thanks to all who came to my presentation on rocketry and lab design. All of the examples of student work, website links, and the presentation itself are available on the right side of this blog site.

Torsional Pendulum Design Lab

Without a doubt, the most successful IB design lab I have done with my students is this one I created using torsional pendulums. Here is the link to the instructions.

Basically a torsional pendulum (by my definition) is something that twists as it spins, and then untwists. My students made them by taping a 200 g hooked mass to a ruler. Then they suspended the mass from a rubber band. Done.

All students decided to measure the period as the dependent variable. That made good sense as it was so easy to measure. However, they then came up with many different independent variables to test such as……
• Number of coins added stuck to the ruler
• Placement of coins away from the center
• Number of rubber bands (both connected in a chain or parallel to each other)
• Number of twists
• Etc…….

I then had them collect data as well before starting their write up. This seems to greatly help their design write-up. As a result I had several students demonstrate great understanding of controlling variables, and thus score very highly for internal assessment.

I also had the students analyze their data and write a conclusion and evaluation. I got mixed results for this. For some experiments there is not much to be done in analyzing the data. Students also struggled in their conclusion and evaluation. When I to do it again, I will only mark the design criteria of this lab.

Experimental Design with Rockets (10th grade)

Richard and I recently introduced our 10th grade General Physics students to Experimental Design through the use of rockets. This then also led nicely into a lab on data collection and analysis, as well as conclusion and evaluation. Here’s how it worked.

Step 1: We had students build rockets that could be launched by our school’s affordable stomp launchers.

Step 2: We launched rockets and if they flew poorly, the students made modifications.

Step 3: We gave the students a contextualized assignment in which they were to assume they were a rocket scientist for a country of their choice in the early 1900’s. They then had to design an experiment involving rockets, and then write a letter to their government seeking funding to carry out their research.

Step 4: We marked the labs and for the best experiments, we awarded “research grants” to these students.

Step 5: Those students with the research grants were assigned a team of scientists to carry out the research. All students then collected data.

Step 6: Students individually analyzed the data through graphs on Excel and then wrote a conclusion and evaluation as well. These were submitted (in soft copy obviously!) and feedback given.

Middle Schoolers Love Rockets

Middle school students and teachers found rockets just as useful for experimental design.
Over the past two weeks my colleague at ISM, Cory, used our school’s rocket launchers to teach experimental design. They did much the same activity that my school students did earlier in the year.
They differed slightly in that they did not use sand bags to drop on the launcher, and thus compress the bottle. That can be a bit tedious, so instead they had students attempt to control the variable of force by stepping off a chair of a constant height onto the bottle. It seemed to work pretty well.

Student notes for Astrophysics!

The ESA (European Space Agency) rocks hard! I was halfway into making a bunch of astrophysics material for my students as we begin the "Option E: Astrophysics" next week. Then I discovered that the ESA has already produced "Teachers Notes" that relate almost exactly to the IB syllabus. If you are teaching this option, you'd be crazy not to use these.

Nuclear Animation

In standard level IB physics, my seniors are currently studying topic 7, Atomic and Nuclear Physics. I have never been overly excited about drawing the models of the atom and the diagrams for the Rutherford experiment to find the nucleus. To ease the boredom a bit, here are some helpful links.

Here is a picture of plum pudding. I have only found about 6 people in the entire world who have ever eaten it. Thus, this picture will be essential to students’ understanding of Thomson’s Plum Pudding model of the atom.

Here is a great animation (with dialogue) about the Rutherford Experiment, aka the Geiger Marsden Experiment.

Lenz's Law Lab (a celebration of the letter L)

Here is a great lab for investigating Electromagnetic Induction and Lenz’s Law (topic 12). Myself and Mike modified this lab from our friend Gary Piech. Basically it’s the demo where you drop a magnet down a copper or aluminum tube and it goes really slowly, much to astonishment of all watching. (note astonishment in picture). In this case coils of wire are wrapped around the tube (in series) and connected to a current sensor. Our students analyzed the current spikes in the loops versus time. They will then explain how these results (which turn out to show terminal velocity of the falling magnet) support Lenz’s and Faraday’s Laws.