Ok there are lots of video's on U-Tube. Millions being added each day.
Some have more value than others to say the least,
but when you have a video that is useful, you can now add a quiz to it to make it more interactive.
Looking for a way to add a short Quiz to a video.
This site is designed for students learning english but could be used for any level, as teacher can design their own questions.
How to Find a Niche Market