Question about the program Datastudio

[haushofer]

Question about the program "Datastudio"

Hi there,

I'm constructing a practical about oscillatory motions. I'm doing this with rotary motions, and for the dataprocessing I'm using the program "Datastudio". Nice program, but I have 1 problem: I don't know how to symmetrize graph's.

So, i 'create a new experiment', plug in the devices, and then I go to the graph. Now I can watch the oscillations of the rotating disc. At the X-axis I have the time, at the Y-axis I have the amplitude in degrees. But for some datafitting I would like to have the graph symmetric around the X-axis; so that the program automatically sets the beginvalue of the angle at zero. Has anyone an idea how to do this?

 

[andrevdh]

I am using the older version of Pasco software - Science Workshop. If one left click on the axes a dialog window opens where you can set the minimum and maximum values for the axes.

Another way that might do the trick is to click on the zoom tool (the magnifying glass). Then drag over the part of the graph that you want to display in the graph area.

Some of the DataStudio manuals can be download from:

http://www.pasco.com/datastudio/home.html#details"

 

[haushofer]

Mmm, I don't have the set-up and the program available right now, but I've tried to adjust the scales of the graph. The only thing I can accomplish is to "lock the origin", or lock the axes themselfs. But I can find a menu to put the initial angle at 0, so that I get my graph's nicely symmetric around the X-axis. Ofcourse, one could manually symmetrise the graph and use those points to draw conclusions, but I can't believe the program hasn't got an option for this. The manual you are given doesn't provide an answer tp this, but it is useful by the way !

Also, I am not able to fit given graphs correctly. What I want is this: with an underdamped harmonic oscillation, the amplitude decreases exponentially. In the exponent, there is a given damping factor, and I would like to put the maxima and minima in a table, draw a graph from it and fit an exponential function with it. From this I want to get the dampingfactor.

 

[andrevdh]

By clicking on the axes I mean that you position the mouse on one of the axes in the graph area - that is on the region where the graph ticks and coordinates are displayed and click in this region. See if that does not present you with a dialog where you can adjust the display.

To change an exponential graph into a linear one you need to plot the natural log (ln) of the independent value (the amplitude) against the dependent variable (the time). The gradient of the resulting linear graph will be the negative of the damping coefficient $-\gamma$. I might be wrong but I don't think you will be able to use your recorded data to do this, that is draw a graph with just the amplitude values. For this to work you will need to create a separate data set with just the (time,amplitude) coordinates. In Science Workshop I entered the data in a text file (notepad) and imported it. The coordinates can then be used to draw a graph (in SW. DS probably have some fancy features to achieve this, but if you don't have access to the user manual will proof quite a daunting task to achieve). If I were you I would just do it in Excel before it drowns all the fun of doing the experiment until you have gained more experience with DS.

 

[haushofer]

I see I did a typo; The story is that I still can't symmetrize the grap around the t-axis ( or X-axis ). If i double click on that region, I get a screen with "Graph Settings", and at the "axis settings" I can lock the origin, but that isn't a great help.

I was indeed intended to do the graph's in Excel.

Anyway, I appreciate your effort to solve this conundrum :)

 

[andrevdh]

Can't you find a setting for changing the maximum and minimum values of the axes if you click on the axes?

 

[haushofer]

Can't you find a setting for changing the maximum and minimum values of the axes if you click on the axes?

Yes, I can, but that doesn't help you; it's only usefull for a certain view of the axes, it doesn't change the coordinates themselfs.

 

[andrevdh]

I thought I understood your problem, but now you've got me confused. By choosing appropiate minimum and maximum values for the y-axis (y-displacement of the oscillator) you should be able to get a symmetrical view of the graph. I do not understand what you mean by the statement that you want to change the coordinates?

Anyway, the option "lock the origin of the axes" makes me think that you might be able to drag the origin of the axes in the graph area. Have you tried that?

Oh, I think I now have an idea what you are trying to do. You want to displace the graph along the time axis. This is done by creating a calculation with the calculator. In this calculation you need to subtract (or add) the time at which the first intecept with the x-axis occurred from the measured time. Once you have created such a calculation you just select it from the panel next to the x-axis. This will then shift the graph along the x-axis so that the oscillations start at zero degrees.