Python/C2/Plotting-the-data/English-timed

Visual Cue	Narration
0:01	Hello Friends and Welcome to this tutorial on "Plotting Experimental data".
0:05	At the end of this tutorial, you will be able to, Define a list of numbers. perform element wise squaring of the list. Plot data points. plot errorbars.
0:18	One needs to be familiar with the concepts of plotting mathematical functions in Python.
0:23	We will use data from a Simple Pendulum Experiment to illustrate.
0:30	As we know for a simple pendulum, length L is directly proportional to the square of time T.
0:37	We shall be plotting L and T square values.
0:40	First we will have to initiate L and T values.
0:44	We initiate them as sequence of values.
0:47	We define a sequence by comma separated values inside two square brackets.
0:52	This is also called a List.
0:54	Let's create two sequences L and t.
0:58	L = [0.1, 0.2, 0.3, 0.4, 0.5,0.6, 0.7, 0.8, 0.9]
1:10	T= [0.69, 0.90, 1.19,1.30, 1.47, 1.58, 1.77, 1.83, 1.94]
1:29	To obtain the square of sequence T we will use the function square with argument T.
1:36	This is saved into the variable Tsquare.
1:38	So type Tsquare=square withinbracket T
1:55	Tsqaure enter
2:00	Now to plot L versus T square, we will simply type
2:07	plot within bracket L comma Tsquare comma dot in single quote
2:21	dot here displays the plot in a dot pattern.
2:26	You can also specify 'o' for big dots.
2:31	For this let us clear the plot first.
2:34	Type clf bracket enter
2:39	Type plot within bracket L comma Tsquare comma o in single quote enter to clear the bracket type clf bracket
3:01	Let us move further.
3.03	For any experimental there is always an error in measurements due to instrumental and human constraints.
3:10	Now we shall try and take these errors into account in our plots .
3:17	Pause the video here, try out the following exercise and resume the video.
3:21	Plot the given experimental data with large dots.
3:25	The data is on your screen.
3:29	Its given in delta underscore L and delta underscore T
3:37	We shall again initialize the sequence values in the same manner as we did for L and T.
3:48	Now to plot L vs T square with an error bar we use the function errorbar().
4:00	Before plotting the data we need to get the data of delta underscore L and delta underscore T
4:05	delta underscore L= within square bracket 0.08,0.09,0.07,0.05,0.06,0.00,0.06,0.06,0.01
4:25	delta underscore T= [0.04,0.08,0.03,0.05,0.03,0.03,0.04,0.07,0.08]
4:40	Now use the error function
4:44	Type errorbar within bracket L comma Tsquare comma xerr=delta underscore L comma yerr=delta underscore T comma fmt=bo in single quote
5:32	This gives a plot with error bar for x and y axis.
5:36	The dots are of blue color.
5:38	The parameters xerr and yerr are error on x and y axis and fmt is the format of the plot.
5:46	similarly we can draw the same error bar with small red dots just change the parameters of fmt to with in single quote r dot.
5:59	Type clf() errorbar within bracket L comma Tsquare comma xerr=delta underscore L comma yerr=delta underscore T comma fmt=within r.
6:24	you can explore other options to errorbar using the documentation of errorbar.
6:30	errorbar? on terminal
6:38	Pause the video here, try out the following exercise and resume the video.
6:44	Plot the given experimental data with small dots and also include the error in your plot.
6:51	The data is on your screen delta s delta n
7:00	This brings us to the end of the end of this tutorial.
7:03	In this tutorial, we have learnt to, 1. to declare a sequence of numbers using the function array.
7:09	2. to perform elementwise squaring using the square function.
7:14	3. to use the various options available for plotting like dots,lines.
7:20	4. to Plot experimental data such that we can also represent error by using the errorbar() function.
7:28	Here are some self assessment questions for you to solve
7:32	1. Square the following sequence. distance underscore values=wthin square bracket 2.1 comma 4.6 comma 8.72 comma 9.03
7:44	2. Plot L versus T in red pluses.
7:52	And the answers,
7:55	1. To square a sequence of values, we use the function square
8:02	Type square within bracket distance underscore values
8:09	2. We pass an additional argument stating the desired parameter
8:14	Type plot within bracket L comma T comma within single quote r+
8:24	Hope you have enjoyed this tutorial and found it useful.
8:27	Thank You!

Contributors and Content Editors

Gaurav, Minal, PoojaMoolya, Sneha