Great question Leigha.
Well, imagine what records used to be like. The old style needle that your dad might have used when he was your age. This is based on tiny holes being made on a sheet of circle of plastic which a needle bounces in and out of.
Well, CDs and DVD are quite like that, only instead of a needle it “reads” the disc using a very precise beam of light known as a laser. And because a beam of light is much smaller than s needle point we can make the marks on the disc much smaller, and pack more information onto the same size piece of plastic!
DVDs are even cooler because there are two layers on each disc. Like a double decker bus. One beam of light reads one layer and another beam reads the layer underneath! Meaning you can get fit TWICE the amount of information on it!
Computer put movies onto these discs by “burning” tiny holes onto the disc using an even more powerful laser. Pretty cool eh!? Kinda like Stars Wars but in miniature….