Intro: The purpose of this lab was to familiarize ourselves with the logger pro graphing program by using it to calculate the acceleration of gravity using a ball, a lab-pro, a motions detector and the program.
Materials: ball, logger pro, computer, lab pro device and a calculator.
Procedure: We started by plugging in the lab-pro to the computer. We opened up the program and started tossing the ball to start our trials. We had to do a few test runs to make sure the timing between the person clicking the button and the person throwing the ball was on point. To collect the data, we pressed a button called "collect" to start the data collection. A parabola came onto the screen. The ball's path is a parabola because of its motion in the air follows a parabolic shape. The velocity graph is a straight line because the derivative of a parabola is a straight line. We fit the curve to a get a quadratic equation (a t^2 + b t + c). The "a" value is half of g (roughly), and so we doubled "a" to get g. We then compared it to the slope of the velocity graph to get our results below. To properly see our line, we had to rescale our y-axis to be able to account for the negative velocity given. On the velocity graph, the fit line for the acceleration of gravity is shown to be negative due to the motion detector taking the motion moving toward it as a negative value. The percent difference of the actual value of g, which is 9.8, is calculated by taking the value we got from doubling our "a" value and subtracting it from the actual value. Then taking that number and dividing it by the actual number. Our percent difference was good for a scientific experiment, hovering at or below 1%.
Conclusion: This lab was relatively short but a good experience to get to know the program. We found our sources of error to be the metal bar in front of the detector, air resistance, human error and how precise we were with our calculations.
