Bests & Worsts Reviews from Amazon

I needed a simple prism for a photography experiment, but when I came to Amazon I found pages of negative reviews on just about all of them. In the end I settled on this one, but I'm now convinced that any of them would have worked just fine. If you shine a collimated beam of full-spectrum light (sunlight works great!) at this prism you can see the dispersion light into its various wavelengths (rainbow). Unfortunately Amazon is getting a growing number of negatives reviews on products due to user error/ignorance. Instead of learn something most are quick to pick up the laptop and vent their frustration. Ironically in this case, the product is a teaching device where the user error is exactly what the device is intended to teach. If it's not working then you're doing something wrong and it's a great time to learn about collimation, light spectrum, and incident angle. Yes, this one is acrylic, no it doesn't matter. The light transmission of acrylic is far greater than that of the low quality glass you would get for a prism this cheap. This one is hand-sized, big enough to disperse a decent size beam, wide enough to be stable to stand on end. My only gripe is that the edges are filed to prevent chipping but that only effected the ascetics of my photographs, not the function of the prism. For most users the filing is probably a good thing. [...]