Yes! Blu-ray players are backward compatible, meaning they can not only play Blu-ray discs, but also DVDs and CDs. Some may even be able to play a wide variety of multimedia files (e.g. MP3, MPEG4, AVI) saved on USB thumb drives and data discs.
Next time you find yourself in a classroom equipped with a Blu-ray player, don’t panic! Simply use the player the same way you would use a DVD player, and you should be all good.