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.
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