Finding Binky went rather well on a Wednesday morning. In the afternoon I opted to deploy the redesigned laboratory seven. The new design once again simplifies a laboratory that has continued to remain confusing for the students. The redesign puts a linear relationship into the core of the laboratory, including a graph.
In retrospect I should have simply subtracted the starting longitude. The class walked east on a line of latitude. Not "zeroing" the longitude data leads to a large and rather meaningless y-intercept. Future runs should deduct the starting longitude when walking along a line of latitude.
I chose to roll the surveyor's wheel while the students held the GPS units. The surveyor's wheel is not zeroing properly any longer and I did not want to potentially introduce errors due to misreading the surveyor's wheel counter. Every 100 feet I had the students report their longitude value. These distances were logged at "30 meters" rather than the 30…
After a brief mention of the formula for momentum, I moved to cover Newton's three laws as formulated from a momentum perspective. Momentum unites the first two laws nicely into variations of the same formula.
I rearranged the tables in A101 and rode my RipStik while a ball balanced loosely in my outstretched hand. I collided with a table on one side of the room, and the ball kept on going. Not as vivid as the outdoor demo I did last spring under the solar panels. The greater speed made a lot of difference.
Then I used the new clothes line rope to hold 8 kg up. I used this to pull me. The 50 cm drop that the table top provided was insufficient to gain much speed. Not much better than 65 cm/s². Still, that provided the numbers I needed to work out what my acceleration must have been. Note that measuring speed post-acceleration, while not ideal, is far easier than timing the acceleration directly. One is rather busy getting accelerated, thoughts of timing are secondary.