Nyquist–Shannon sampling theorem

The Nyquist-Shannon sampling theorem tells us that if we want to accurately represent a signal (like a sound or a picture), we need to sample it a certain amount of times. The amount of times we need to sample it is twice as high as the highest frequency of the signal. It's like if you want to draw a really detailed picture of something, you need to draw it with a lot of tiny dots close together. The same thing goes for sound - if you want to record a sound without making it sound weird and distorted, you need to record it with a lot of tiny samples.