VERNIER SOFTWARE PHOTOGATE TIMER AND THE TI CBL AND TI-92 Note: This document was prepared using Courier font at size 10. To view this file in its proper format, select all contents and set to Courier 10. I. OVERVIEW This document describes the use of a program that allows you to do various event timing experiments using one or two photogates with TI-92 calculator and the TI Calculator-Based Laboratory (CBL) System. The photogates supported with this program will require an adapter, either the single photogate adapter (order code CBL-P) or the dual photogate adapter order (code CBL-2P) each available from Vernier Software. This program supports Vernier Software Photogates, PASCO Photogates and PASCO Smart Pulleys in four different modes of operation. Please note that this program will not work with the TI light probe. The program is large enough and complex enough that a separate directory, called TIMER, will be created when you load the PHOTGATE program onto the calculator. II. PROTECTED PROGRAM FILES This file has been protected so that it cannot be edited on the calculator. This feature prevents students from accidentally editing a program. The easiest way to edit protected files is with the TI-Graph Link program. The TI-Graph Link manuals describe the protecting and unprotecting process. III. LOADING AND RUNNING THE PHOTGATE PROGRAM ONTO THE TI-92 To provide the flexibility desired in this program, a separate directory has been created on the TI-92 for this program and the supporting lists and variables. The easiest method of loading this program is to transfer the PHOTGATE.92p file through the Send option with TI-Graph Link. It is important that the original folder be sent with the program. If you are using Graph Link for the Mac, make sure that the "Send to Original Folder(s)" box is checked. If you are using the Windows version of Graph Link, be sure that the "Retain Folder" box is checked. This program provides a wide range of options as you set up and run experiments. After the program has been loaded, run the PHOTGATE.92p program. This is done by first pressing the [2nd] [VAR-LINK] keys. A list of all the files and directories on the calculator will appear in a pop-up screen. Use the cursor pad to locate the TIMER directory. Scroll through this directory to find the PHOTGATE program. Press [ENTER] to return to the Home screen. The Entry Line will display "timer/photgate(". Press the right parenthesis ")" followed by the [ENTER] key. The Main Menu will then appear. IV. GENERAL DESCRIPTION OF THE PROGRAM _______ __________ _______ ________ ____ / F1 \/ F2 \/ F3 \/ F4 \/ F5 \ | Setup | Experiment | Start | Display | Quit | |_______|____________|_______|_________|______| | Mode:Check Gate | | X | | X | | X X | | X X | | X X | | X X | | X Vernier Software | | Photogate 11/10/95 | |_____________________________________________| The above represents the Main Menu as it would appear on the calculator. The top portion of the screen contains tabs that are used to collect data and view graphs. In the middle section you will find the current data collection mode, a representation of a photogate, and the program name and date. The tabs shown in the top of the display represent operations that are accessed by pressing the functions keys located to the left of the calculator display. These operations are: F1 Setup - This tab reminds you to plug the photogate adapter into channel 1. F2 Experiment - Selects the data collection mode. F3 Start - Starts the experiment. F4 Display - Is used to view graphs. F5 Quit - Exits the PHOTGATE program. The following general description applies to the use of this program on the TI-92 calculator. A. [F1] SETUP - This option reminds you to connect the photogate adapter into channel 1 on the CBL. This applies to both the single and dual photogate adapter. B. [F2] EXPERIMENT - Choosing this option produces a pop-up dialog box with a list of data collection modes. Data collection mode will begin after you press [F3] START while at the Main Menu. The list of data collection modes is the following: 1:Check Gate 2:Motion 3:Gate 4:Pendulum 5:Pulse These options represent these modes: 1:Check Gate - This option provides a check of the photogate and the calculator displays a screen showing the status of the photogate. Slowly move an object through the photogate to verify that it changes between the blocked and unblocked states. 2:Motion - This option allows you to use a photogate or a Smart Pulley to collect data and view distance, velocity and acceleration graphs as a function of time. After you select this option, a pop-up dialog box will appear from which to choose a type of device. These devices include: 1:Vernier Picket 2:Smart Pulley 3:Custom The Vernier Picket option refers to a picket fence containing eight opaque bars separated by seven clear bars. The distance between the leading edges of the opaque bars is 0.05 m. The Smart Pulley options refers to a number of Smart Pulleys manufactured by PASCO scientific. Two different Smart Pulleys are available with two modes of operation. You must select the proper Smart Pulley and operation mode from this list: 1:10 spoke inside 2:10 spoke outside 3:3 spoke inside 4:3 spoke outside These options refer to the Smart Pulleys containing either three or ten spokes operating in two different modes. In one mode a string is pulled through the groove in the pulley. In the other mode the pulley is spun by an object on the outside edge of the pulley. If you choose 3:Custom Device option in the Select Device pop-up menu, you will be asked to enter the number of opaque objects in the picket fence or bar tape and the distance between leading edges. After choosing the data collection mode for motion timing, you must start data collection by pressing the [F3] while at the Main Menu. Be sure to follow the directions displayed on the calculator. Note: If you have selected a Smart Pulley, you will be asked to estimate the number of revolutions. This estimate will tell the CBL when to stop collecting data. After the data is collected, a graph of distance vs. time will appear with the following menu bar: F1 F2 F3 F4 Options Graphs Regression Return OPTIONS [F1] - The [F1] key reveals this pull-down menu: F1 Options 1:Trace 2:Range 3:Autoscale 4:Autoscale from 0 5:Plot type and marker 6:Show Ranges 7:Select region These graphing options are: Trace - Turns the trace options on. While viewing the graph, you can use the cursor pad to trace the data points on a plot or plots. As you press the left or right edge of the cursor pad, the coordinates of each data point appear on the bottom of the graph screen. To move to another plot on the graph, press the top or bottom edges of the cursor pad. Pressing [ENTER] turns off the trace option. Range - This option displays the window ranges of the current graph in a dialog box. You can modify the ranges on the x- and y-axes by entering new values and using the cursor pad to move between the different fields. Autoscale - Selecting this option causes the graph to be automatically scaled based on the data. Autoscale from 0 - Selecting this option causes the graph to be automatically scaled based on the data but the origin is included in the graph. Plot type and marker - Use this option to change the type of graph and the marker used to plot the points. A pop-up menu is used to select the plot type, marker, and to which graphs these selections apply. Show ranges - This option will add the x- and y-axis ranges to the graph. To turn off the ranges select the options 3, 4, or 5 in this menu. Select region- You can use this option to select a region of a graph. After the option is selected, the graph will appear and you will be prompted to move the cursor to the lower limit of the graph. Use the cursor pad to move to the left portion of the region of interest. Press [ENTER]. Move the cursor the right and press [ENTER] again. The selected region will now appear on the graph. GRAPHS [F2] - Use this option to select one of three graphs: distance vs. time, velocity vs. time, or acceleration vs. time. REGRESSION [F3] The [F3] key reveals this pull-down menu: F3 Regression 1:Best-Fit Regression 2:Regression Statistics The Best-Fit Regression option allows you to apply any one of eight different regression models to the current data. The Regression Statistics option displays the regression model and the regression statistics. RETURN [F4] This option returns you to the Main Menu. 3:Gate - The third collection mode, 3:Gate, records the time(s) that a photogate or two photogates are blocked. After you start this mode, you will be directed to move an object through a photogate to arm the gate. The CBL will then record the time when the next object passes through the photogate(s). 4:Pendulum - The fourth collection mode, 4:Pendulum, measures the period of a pendulum as it travels back and forth through a photogate. You will be asked to enter the number of oscillations. The CBL will measure the period of this motion and report the average. 5: Pulse - The fifth collection mode, 5:Pulse, is used with two photogates. During data collection this mode measures the time that an object takes to travel from one photogate to the next. This mode will be most valuable with the dual photogate adapter. C. [F3] START - After you have selected a data collection mode, press the [F3] button while at the Main Menu to begin collecting data. Each data collection mode operates differently. After you start the data collection, the calculator will provide directions for that mode. In the case of the Motion timing mode, the CBL and calculator will each display "Ready". You can then send the picket fence through the gate or allow the Smart Pulley to begin moving. D. [F4] DISPLAY - Use this option to view and analyze graphs produced when you use the Motion data collection mode. E. [F5] QUIT - Select this option to quit the program. V. DATA STORAGE Data collected with this program is stored in a data set called “photodat” found in the timer folder. Data collected in the Gate or Pulse mode will be stored in columns 1 and 2 in this data set. Pendula data will be stored in column 3. During the data collection, a pop-up dialog box will remind you where the data is stored. When you choose the Motion mode, data is stored in the following columns in the data set: C1 - time for distance measurement C2 - distance C3 - time for velocity measurement C4 - average velocity C5 - time for acceleration measurement C6 - average acceleration VI. POSSIBLE ACTIVITIES Here are some suggested experiments that can be performed with this program and a photogate. 1) Use the pendulum timing mode to investigate the factors that affect the period of a simple pendulum. Suspend a pendulum bob so that it blocks and unblocks it as it passes through the photogate beam. Determine whether the period changes significantly if a) the pendulum arc length changes, b) the mass of the pendulum changes, or c) the length of the pendulum changes. 2) Use the single gate timing mode to measure the linear speed of an object as it passes through the photogate. 3) Use the motion timing mode with a picket fence to study its motion during free fall through the photogate. 4) Picket fences or bar tape can be attached to dynamics cart or toy cars to study linear acceleration and deceleration. 5) Labs designed for the PASCO Smart Pulley can be performed with this equipment by selecting the motion timing mode and the appropriate Smart Pulley. A wide range of experiments in kinematics, dynamics, momentum, energy and rotational motion are possible. Refer to the PASCO Smart Pulley manual for specific details. February 28, 1996 Rick Sorensen Matthew Denton Vernier Software 8565 S.W. Beaverton-Hillsdale Hwy. Portland, OR 97225-2429 phone (503) 297-5317 fax (503) 297-1760