Can you name those glasses?

[dsllcd]

Hi! So I got those glasses from my science teacher at my school for 25 cents and I'd like to know how they're named so I can buy more online.. Since I didn't know where I could post this on the internet I typed science forum on Google because it still has a little connection with sciences I think and this was the first result. Since this seems like a serious science forum I'm posting this in the general talk section.

 

So what's the name of those glasses? Every light sources have colored trails coming from them and every objects have multiple "ghost" version around them. Here are pictures taken with my webcam seeing through the glasses.

 

 

 

 

[Fuzzwood]

Looks kinda like a kaleidoscope, but with real objects.

[John Cuthber]

diffraction grating.

[Sato]

That looks like diffraction grating film, which separates the individual color components of incoming light.

[dsllcd]

Thank you so much! I knew it separated light but I would've never known it was called "diffraction grating"!

[ajb]

You can make a basic spectrograph using the clear CD you get in the pack of writable CDs for your computer.