Saturday, March 28, 2009

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.

Tuesday, March 17, 2009

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.

Sunday, March 15, 2009

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.