Apologia Physics: Module 3 Labs

Okay, we adapted both the experiments from Module 3.  One of the kids had missed the ball drop-so, we repeated it.  The kids used a tape measure and marked a spot on the wall at two meters.  They stood on chairs and dropped marbles.  The guys recruited McGregor and Caeli to time the ball drops.  Kobe  recorded the times for everyone.  Listen, you need to time the ball drop a dozen trials or so before recording the times.  It isn't easy to hit 'stop' when the marble drops.  We tried having the kid drop and time unsuccessfully.  At two meters, the average time was about 0.44 s.  Acceleration owing to gravity is 9.8m/s2.  Our marble drops were close.  My husband, Rob, tried to explain to all of use that this measure is inaccurate.  Finally, in the car, on the way home, I got it.  To be accurate, we should calculate average velocity at 2 m, 1.5m, 1 m, and .5 m and then calculate average acceleration.  The problem is that our reflexes aren't sharp enough to be accurate trying to time distances less than 2 meters.  Next, we spent time going over the test from Apologia for Module 2.  Truthfully, I like to review tests together after the kids take them to clear up any misconceptions.  Frankly, I'm not interested in the grade as much as I'm interested in them understanding the material.  Lastly, we did the reaction time experiment from Module 3 with this formula, seen here in this lab.  The kids collected 15 trials with the ruler.  We gave them the formula for distance and they had to figure out how to solve for t, time, specifically reaction time.  The guys collected data in cm and immediately understood to convert centimeters to meters.  Yeah!  Joey had the lowest average of the four guys, but his answer was the highest.  Break through!  Joey told me something wasn't right; his reaction time should be lower than everyone else's times.  Yeah!  I looked over his calculations, redid them myself and saw where he had copied a number incorrectly.  Done!  Most importantly, Joey had an intuitive understanding that his time should be lowest and when it wasn't wanted to see if his calculation was off.  Rob and I were so pleased we told his mom.  I tell the kids that I can usually figure out what they did incorrectly because I've made every one of the same errors.  Pictures of lab