Question: what's one of the weirdest things you have had to 'trap and move?'

Guido Bolognesi answered on 9 Mar 2015:

Hello Maddy,

For the moment I have only trapped glass/plastic beads and liquid drops,
so nothing too weird really.

However, the optical trapping technique has been used to trap other stuff more exciting than plain beads. For instance, scientists have trapped living bacteria in order to study the way they move. Other people have attached the ends of a single strand of DNA (do you know about DNA?) to two glass beads and then moved the beads apart with lasers. In this way, they managed to test the mechanical property of a single strand of DNA in the same way you would test the rigidity of a rubber band by moving two ends of it apart with your fingers.