One of my STEM Mentees proposed a question to look at and discuss with them:
'I would like to share an interesting physics puzzle I've stumbled across. Feel free to give it a go : A mote ( a small speck of something, a dust particle for example ) is at the centre of a perfect sphere of glass. Where, if anywhere, do you see the mote?'
Would anyone care to join in on the answer?
Looking at the first diagram from Mike the object is at >2F distance from the lens and the image is at <2F distance. So you would see the mote in the direction of the centre of the sphere, but it would be closer than the actual centre. If you spin the sphere it would not appear to move, but the apparent position of the mote would form a circle.
Think that's right.
Edit; so it would be a moat.
Looking at the first diagram from Mike the object is at >2F distance from the lens and the image is at <2F distance. So you would see the mote in the direction of the centre of the sphere, but it would be closer than the actual centre. If you spin the sphere it would not appear to move, but the apparent position of the mote would form a circle.
Think that's right.
Edit; so it would be a moat.
I'd read the description as more like this, in which case it wouldn't move:
