I use this demo in class.
Put the files
into a directory. Open the file Order2Gui.m with Matlab, and hit run. You should get an image like the one below.
Choose the type of system with radio button at lower right. Choose natural frequency (wn) and damping ration (z) with sliders, or by typing into text boxes below sliders. Choose responses you wish to look at with check boxes.
If you want to compare responses, hit the hold button. To clear screen, clear button. To exit, exit button.
The first response takes some time to appear (Matlab needs to load toolboxes), after that it is pretty quick.
Error checking is non-existent (I only wrote the program for me to use - if you want to edit code to add error checking, let me know). For example, if you close one of the windows that the program opens (e.g., "Step Response," "Bode Plot"...), it gets very unhappy and you may have to quit and restart.