[katieHaylor (OP)]

Geoff asks:

How do you measure the strength of a magnifying glass?

Can you help?

[RD]

The power of a lens, in dioptres, is the reciprocal of the focal-length in metres ...
http://www.bbc.co.uk/bitesize/intermediate2/physics/waves_and_optics/power_of_lens/revision/1/

The focal-length is the distance between the lens & the cremated ant ...

[Bored chemist]

However, that doesn't actually tell you the magnification.
I'm short-sighted. The lenses in my glasses are thinner in the middle than at the edge.
The make things look smaller, so the "magnification is some fraction between 0 and1.
But the power in dioptres is about  -10.

The magnification of a lens depends on how closely you can focus without it.

https://en.wikipedia.org/wiki/Magnification#Single_lens

[evan_au]

How do you determine the magnifying strength of a lens?

If you need great magnification (eg a microscope or telescope), you often use a compound lens, with multiple elements - calculating the magnification gets a lot more complex.

Designers of microscopes and telescopes will often sacrifice some magnification in order to reduce "chromatic aberration", colored fringes around the image.
See: https://en.wikipedia.org/wiki/Chromatic_aberration#Minimization

[glot]

I find the burning ant example offensive.

[Bored chemist]

I find the burning ant example offensive.

Do you have a problem with cremation?
I know some cultures prefer burials etc, but I don't think those requirements are usually applied to insects.