This short activity provides practice with using a spark times to measure motion over very small time intervals. Spark times will allow us to do some basic investigations of gravity, so it's worth spending some time getting used to them.

This can become a very tedious lab if you're unfamiliar with using Excel to create data tables and graphs, so feel free to ask if you need a hand. If you decide to create the graphs by hand, be prepared to spend a good deal of time doiing it right.

Because this lab is only for practice, you don't need to perform a full writeup.

In this lab, we’ll use spark timers to find out who has the quickest hands around.

Some pitchers can accelerate a ball to over 100 mph. Predict how fast you can you move your hand. ______

To find out, we’ll pull paper through spark timers.
Spark timers place marks on pieces of paper tape at regular time intervals of 1/60th of a sec.
You’ll pull paper through the ticker as fast as you can to measure your acceleration and hand speed.

Place your paper in the spark timer so the conductive (shiny) side touches the two spark contacts.
Pull the piece of the ticker tape through the ticker rapidly without the paper getting caught or torn.
You must shout “WHEEE!” or your paper will be thrown away.

You should get a pattern like the one below.

Data Table: Make a data table that looks like this one.

Time Elapsed

Total Distance Traveled

Distance Between Dots

Velocity

 

Analysis Part One (Total Distance vs. Total Time):
Graph total distance (y-axis) vs. total time passed (x-axis).

Analysis Part Two (Instantaneous Velocity):
Graph the velocity of your hand (y-axis) vs. total time passed.
Convert your maximum velocity into mph.
Calculate your acceleration (calculate the average extreme slope on your velocity / time graph).

Questions:
1. Did your graphs show a constant acceleration? Explain. 3 points
2. Where in the travel of the tape was your velocity the highest? How do you know this? 2 points