Refractive index of aquarium glass

[hipslap]

Hi, I am interested in the RI of glasses used in aquariums.

I've found that Acrylic glass has a RI of 1.49 and Starfire glass has an RI of 1.52.

I haven't been able to find any information on run of the mill, standard aquarium glass that you would find on a tank bought at a store like Petsmart. Does anyone know what the RI of typical aquarium glass is?

Also, do certain companies use different blends of materials to produce clearer glass then their competition? Other then Starfire, which I believe is a brand, are their other types of clear glasses?

One more question. Is their any glass that has a lower RI than Acrylic Glass that is viable for use in aquariums? Thank you!

As I continue to search I see that Pyrex (borosilicate glass) has an RI of 1.47. Why is Pyrex never used to build aquariums?

 

[disc1]

The glass in your run of the mill aquarium is not so tightly controlled. It's going to depend on brand and such. The RI will be around the 1.5 range for most glasses. Pyrex is not very clear and that probably has something to do with why they don't use it. It's also not as strong to shock I think.

 

[hipslap]

Cool, thanks. I assumed refractive index and clarity were related. Looks like I have lots to learn!

 

[aleonn]

You can also ask/email the various manufacturers directly. I've never thought about the RI of our tanks actually, so it would be interesting to know.

 

[disc1]

refractive index won't have anything to do with clarity. Low RI glass will make a difference in the distortion you see when looking through it at an angle. Although I don't know that over the spread of available materials you are going to see any real difference.

 

[hipslap]

Aww, ok. Refraction is the reason my hand and arm don't line up when I stick it in the aquarium. Thanks.

 

[disc1]

Exactly. It's also the reason that when you look at the tank at an angle close to the glass, things look all elongated.

It is also the reason that when you look into the tank from the front, you see a reflection on the sides. That has to do with the difference in RI between the water and the glass. That determines the amount of light that gets out of the tank (refracted) versus what gets reflected. It is a common misconception that fish play with their reflections. While they do see their reflection sometimes depending on the angle, most of the time they see us. If you put your head in the tank and look out, you will see out of the tank with just a slight reflection if any.

 

[SoFloReefer]

Good info disc1. I always though my fish saw themselves, especially when the lights are on.

 

[BrassMonkey]

i dont think they use borosilicate cause of cost to produce. it would seem superior otherwise, esp since its harder to scratch.