Daily lessons coming soon
Beginning Monday 20 April, BBC Bitesize will publish daily online lessons for all ages. We'll also have a new dedicated TV channel full of learning content, podcasts on BBC Sounds and loads of educational video on iPlayer.
Lenses are precisely shaped pieces of glass that have been developed and used in corrective glasses, telescopes, microscopes, binoculars, and magnifying glasses.
Jonny Nelson introduces an animated explanation of lenses