Category Archives: Optics

I’m in the process of writing a textbook for the IOP E-book portfolio that will focus on characterisation techniques, in particular for solid state physics.

This will include:

X-ray and Neutron Techniques
Microscopy Techniques
Spectroscopy Techniques
Magnetic, Electric, and Thermal Characterisation Techniques.

And will, as far as possible make use of open source data to provide real world problems for students to tackle (focusing on data analysis).

I am therefore, actively looking for journal articles that may use one or more of these techniques and where the original datafiles are accessible. If you have work that you think would be relevant then please contact me. Of course all relevant files and journal articles would be referenced.

Double Rainbow

The invisible rod

1 Reply

Challenge: How can you make a quartz rod invisible with some water, sugar and a beaker?

Answer: Snell’s Law

If we take something that is typically transparent (i.e. the quartz rod) you can normally see it quite clearly when placed in a liquid, by the way in which light is bent as it passes through.

This ‘bending’ of light – refraction – can be described by Snell’s law:

$n_{1}sin(\theta_{1})=n_{2}sin(\theta_{2})$

where ‘n’ is the refractive index of the material.

So you might imagine that if we can change the rod, or the liquid itself, so that light entering from behind the beaker does not refract further on entering the quartz rod, we can effectively make the quartz rod invisible. To do this we want to match up the refractive indices ( $n_{1}, n_2$ ).

With water, as you add more and more sugar the refractive index increases, until finally it approaches that of quartz ~1.46.

Kelly Morrison

Professor of Experimental Physics at Loughborough University

Category Archives: Optics

STEM Community Day at Loughborough, 16th March 2019

Science in the Park 2019 – Light Painting

Characterisation Methods in Solid State and Materials Science

Double Rainbow

The invisible rod