Use this Applet to explore the normal and T distributions. Discover how the T distribution relates to the normal distribution by changing the degress of freedom (df) by using the slider. If you would like to hide the T distribution or Normal distribution then click on the check box. To reset the parameters click N(0,1) to have the curve go back to normal distribution.
As the standard deviation (s) changes, how does the normal curve change? What happens to the normal curve if the mean (m) increases or decreases? As you increase the degrees of freedom what do you notice about the T distributuion? Does it begin to look more like the normal curve? Or less like it?