VERNIER SOFTWARE PHOTOGATE TIMER AND THE TI CBL AND TI-85 OVERVIEW This document briefly describes the use of a group of programs that allow you to do various event time experiments using a photogate with TI-85 calculator and the TI Calculator-Based Laboratory (CBL) System. The photogates supported with this program will require an adapter (order code CBL-P) available from Vernier Software. This set of programs supports Vernier Software Photogates, PASCO Photogates and PASCO Smart Pulleys in three different modes of operation. These programs will not work with the TI light probe. Feel free to use these programs in your classes. If you refer to the programs in a written document, please contact Vernier Software. If someone in another school wishes to use the programs, have them contact Vernier Software to receive a disk. This set of programs has been developed for the TI-85 calculator. The programs appear on this disk in a group file. Groups files for the TI-85 always end in the "85g" extension while program files have the "85p" extensions. The extensions on the filenames appear only on the computer and do not appear when you see the program names on the calculator. SENDING GROUP FILES The PHOTGATE.85g file is five programs that have been grouped together. The easiest method of loading all five programs on to your calculator is to transfer the PHOTGATE.85g group file by using the Send Group Files option with TI-Graph Link. MS-DOS users refer to pp. 23-24 in the "TI- Graph Link for IBM-compatibles Guidebook". MS-DOS users may also need to refer to p. 10 for information on changing the directory pathname. Macintosh users refer to pp. 34-35 in the "TI-Graph Link for Macintosh Guidebook". UNGROUPING THE FILES You may prefer to "ungroup" the PHOTGATE.85g file for archiving on a hard drive. Before you do that, it would be best to create a folder or subdirectory on your hard drive for the group file. The programs can then be stored in a common area on your hard drive after being ungrouped. The files can be ungrouped by choosing the Ungroup Files option in the TI-Graph Link program. If you are working with an MS-DOS machine, refer to p. 25 of their Graph Link Guidebook for information on working with group files. Macintosh users refer to pp. 25-26 in their Graph Link for Guidebook. Ungrouping the file will make the following five programs available: TIMER.85p, TMGTSTAT.85p, TMMOTION.85p, TMGATE.85p, and TMPENDLM.85p. You can use TI-Graph Link to download all five programs from the computer to the calculator. Macintosh users refer to page 52 in their manual and MS-DOS users refer to pp. 23-24 in their manual. GENERAL DESCRIPTION OF THE PROGRAMS These programs function together to provide a wide range of options as you create and run experiments. After all five programs have been loaded, run the TIMER.85p program. (Remember, the name of the program will appear as "TIMER" on the calculator). The TIMER.85p program uses a series of menus allowing you to set up different sorts of experiments with the above mentioned photogate systems. The following general description applies to the use of these programs on the TI-85 calculator. For specific help in executing programs on the calculator, refer to the TI-85 manual. To begin, run the TIMER program. After an introductory screens, the following main menu will appear: PHOTOGATE TIMING MODES=timing modes CHECK=check photogate QUIT=quit program The first option, MODES, allows you to select different methods for using photogates and photogate/pulley systems. The next section describes this option. The second option, CHECK, provides a check of the photogate. Choosing this option brings up a screen that displays the status of the photogate. Slowly move an object through the photogate to verify that it changes between the blocked and unblocked states. The third option, QUIT, returns you to the Home Screen where you have access to graphing and statistical ana1ysis features. After checking to see that the photogate works, select the TIMING MODES option and the following menu will appear: **TIMING MODES** MOTIN=motion SINGL=single gate PENDU=pendulum RETRN=RETURN The first option, MOTION, allows you to use photogates and photogate/pulley systems to collect data and view graphs of distance, velocity and acceleration as a function of time. The second option, SINGLE GATE, records the time that a photogate is blocked. The PENDU option measures the period of a pendulum as it travels back and forth through a photogate. Each of these modes is described below. When you select MOTION from the TIMING MODES menu, the following menu appears: *MOTION TIMING* DEVIC=select device COLLT=collect data VIEWG=view graph REPET=repeat experiment RETRN=return The DEVIC option will produce another menu from which you will choose an appropriate photogate device. The options are: SELECT DEVICE PICKT=Vernier Picket PULLY=Smart Pulley CUSTM=custom device RETRN=return The PICKT option is 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. Selecting the PULLY option brings up a list of various photogate/pulley arrangements. SMART PULLEY 10 IN=10 spoke inside 10 OU=10 spoke outside 3 IN=3 spoke inside 3 OU=3 spoke outside These options refer to two different PASCO 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 the CUSTM option in the SELECT DEVICE 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 the device has been chosen, you will return to the MOTION TIMING menu where you can now begin to collect data. If you have selected a photogate/pulley, you will be asked to estimate the number of revolutions. This estimate will tell the CBL when to stop collecting data. You may have to design your experiment with this in mind. After the data is collected you will have a chance to view distance vs. time, velocity vs. time, and acceleration vs. time graphs in that order. After viewing these graphs, you will then have an opportunity to repeat the experiment or return to TIMING MODES menu. You can then return to the main PHOTOGATE TIMING menu. Option two, SINGL, in the TIMING MODES menu will measure the time during which the photogate is blocked. After you select this option, you will be directed to move an object through the photogate to arm the gate. The CBL will now record the time for the next object that passes through the photogate. Option three, PENDU, in the TIMING MODES menu will measure the period of an object as it oscillates through the photogate. You will be asked to enter the number of oscillations. The CBL will measure the period of this motion and report the average. CALCULATOR LISTS When you choose the MOTIN option in the MOTION TIMING menu, pertinent data is stored in lists on the calculator. The following summarizes the arrangement: L1 - time for distance measurement L2 - distance L3 - time for velocity measurement L4 - average velocity L5 - time for acceleration measurement L6 - average acceleration OVERVIEW OF EACH PROGRAM The TIMER.85p program will call the other programs depending upon the options you choose. Each program is briefly described below. TIMER.85p - This is the main program that calls the subprograms. Run this program to begin. TMGTSTAT.85p - This program checks the status of the photogate and reports whether the gate is blocked or unblocked. Move an object slowly through the gate to see is the gate status changes between blocked and unblocked. TMMOTION.85p - This program uses picket fences, bar tapes and photogate/pulley systems to collect distance, velocity, and acceleration data. TMGATE.85p - This program measures the time that a photogate is blocked. TMPENDLM.85p - This program determines the period of an object as it oscillates through a photogate. 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 PASCO’s 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. August 28, 1995 Rick Sorensen Vernier Software 8565 S.W. Beaverton-Hillsdale Hwy. Portland, OR 97225-2429 phone (503) 297-5317 fax (503) 297-1760