Unfortunately, not one of the more interesting days in Advanced Physics. The students were given about 25 minutes to finish gathering data (if needed) and then we had the post lab discussion on the kinetic energy experiment. We established that there s a square relationship between the kinetic energy and the velocity of the system. The disappointing thing is that only a few groups (like 3 of 12) had a slope value anywhere near the 1/2m value it should be. I feel part of this is my fault. When we did the pre-lab discussion, I thought the students had a pretty good handle on what to do, but after about 2 days of data gathering , seems I was not quite right. In the simplest sense, the students were to use a spring to launch the cart; get the energy (using COE energy) from the amount the spring was compressed and the spring constant, then plot that against the maximum velocity (from a motion detector). I know one could do the experiment using a force sensor with the motion detector and calculated columns, but that seems even more abstract. I think for next time, I will have one station, that I monitor to obtain the spring constants… AND everyone using the Pasco launchers rather than the springs inside the carts. I’ll also have to remember to make sure the students have leveled the track and used a different mass than other groups, probably a bit more added to the cart to make it more manageable.
In another day or so we will WB the Gravitational experiment…. really not looking forward to it; but maybe I’ll be pleasantly surprised.
Today we worked on three problems involving Newton’s 2nd Law and kinematics (constant acceleration). Everything is leading up to an assessment and kinesthetic experience… we’re going to ask the kids to determine the coefficient of friction between a sled and snow. That’s right, we are going to go sledding!