How to Use the Graphing Calculator for Science
1. The Basics:
a) Turn it on - bottom left. To turn it off - (2nd)bottom left
b) Adjusting the display to make it darker. The blue button, then the up arrow to darken, down for lighter
c) Normal data entry - just like a regular calculator, except you can chain calculations; try 2x4 (ENTER), +3 (ENTER) to see the difference!
d) The thing that messes everyone up, and you have to remember: order of priorities. Enter 2+3*4 and hit (ENTER) - 14, right? What you meant to do is add 3 to 2, then multiply by 4. To do that, you have to either do it in two pieces (see part c above), or use parentheses: (2+3)*4 works. Parentheses are safer, and a good habit to get into for physics. The calculator does exponents first, then multiply/divide, and lastly add/subtract. Anything else: use the parentheses. When in doubt, use the parentheses.
e) The (enter) key starts the whole thing off, so put the entire problem down, look it over for boo-boos, then hit enter.
f) The other thing that will get you is negative numbers. There are 2 negative keys on the calculator. The one at the bottom next to the enter key is the "negative sign" key, not the SUBTRACTION command key. There's a big difference between these keys for a problem like 4*(-3) = Try 4*-3...
g) Put your name in your calculator. Hit (PRGM), select ‘Create New’ from the ‘NEW’ menu. Type in your last name, you’ll notice letters in green above many of the keys. Hit (ENTER), then (2nd) – (MODE) which is (QUIT). Now any time you hit (PRGM) you’ll see your name.
2. Graphing stuff:
All the data for a graph is stored in "lists" - to get a look at the lists, hit (STAT), then (edit). There are 6 lists available. There are also ways to give them titles, like "time" - this is handy, but not necessary - read your book for details.
Let's enter some data in the lists: put 0,1,2,3,4,5,6 in list 1; and put 0,3,6,9,12,15,18 in list 2. If you make a mistake, just use the arrow keys to go to the wrong number, then enter the right one. To graph the data, hit the (STATPLOT) button on the upper left. This gives you the plots menu. You have three plots available, with choice 4 & 5 turning the whole batch on and off. Select plot 1, hit enter. This is the plot 1 menu. Choices are on/off, type of graph, where the data comes from, what kind of mark do you want. Turn the plot on, pick the first graph choice - points, choose list 1 for the x-axis, list 2 for the y-axis, and the little square box shows up best. Hit the (graph) button on the top right, and you should have a graph. Looks kinda lousy, so hit the (zoom) button on the top row, then choose (9), and it autoscales everything! neato!
This still looks kinda ordinary, so go back to the plots menu, and change your graph type to a line - that's the 2nd choice. Hit zoom 9 again, and that's better.
There's another way of graphing equations on the calculator, mostly used in math class. Use the (y=) button on the top row, enter the equation, hit (graph) or (zoom9), and there it is. You can change the command on the left to shade below the curve, etc. just like you did back in the 9th grade.
How to clear the data in a list: use the arrow keys to move up to L1, then hit (clear), then (enter). DO NOT HIT DEL!!! It's always a good idea to do this before entering any numbers into the lists.
3. Linear Fit – Find the Relationship
OK, at some point I will ask you to find the relationship between two variables. What I’m asking is if X doubles how much does Y change? The more astute will realize this sounds like I’m asking for an equation.
Your calculator can find the equation implicit in a set of data by doing something called Regression. You may have learned how to do linear or quadratic regressions in math class. Your calculator can do all the work for you.
a) Enter your data into your list
b) Hit (stat) and select the ‘calc’ menu
c) Select the regression you want. You may have to think about what your graph looks like and decide which type of function makes that type of graph.
d) By default the calculator looks for your data in L1 and L2.
e) Hit enter and your equation will be displayed.
f) Enter your data into (Y=) and see if it matches your data.
4. Saving hours of homework time:
The REAL timesaver comes in using this little mini-computer to do all your homework! You know how you always get 15 homework problems, all the same.... Tell the calculator how to do one, and it will do all the rest for you! Let's use the data from list 1 again to save all that typing. Look the lists over, you should have 0,1,2,3,4,5,6 in list 1, right? Now let's make a graph of x2. That would mean putting 0,1,4,9,etc in list 2. So lets tell the calculator to do that: Printed in yellow on the calculator over the number 1 is L1, so hit (L1), the (x2) button, then the (sto) button, then (L2), then (enter). Now when you look in the lists there the numbers are. That last command line took all the numbers in list 1, squared them, and stuck the answer in list 2. I want to point out two things:
a) it will do much more complicated things, like (3xL1+4)5 just as fast!
b) it will do a list of 100 numbers just as fast!
Graph the last problem to see a y vs x2 graph. You know, if you wanted a x2 vs y graph, you could just change the plot 1 command so that x-axis is L2, y-axis is L1, and now you have the other graph - try doing that on a piece of graph paper!
4. Like the graph, and want to keep it?
Hit (draw), select (sto), and store the graph on the screen as a 'pic'. You get 10 pics, numbered from 0-9. This is useful to compare graphs. More on this next week during the first labs!
5. Doing Christian Service for your friends:
It's calling "linking" with the calculators, and you got a dinky little cable to do it with in the box with your calculator. The menu to use is (LINK) - both calculators hit that, then one (sends), and the other (receives). Make sure the receiver is receiving first before the sender sends. You can send a whole selection of stuff: the lists, programs, everything, pictures... up to the memory capacity of the receiving calculator. What's handy is the copying of lab data - put it into one set of lists, then link it to the other calculators in the lab group, and send it along.
Another Tutorial on how to use your calculator: