Ask A Scientist© Physics Archive

name         JeffL
status       educator
age          old

Question -   I have been asked to give a science presentation to a 5th
grade class.
I have been thinking of demonstrating a Jacob's Ladder as part of it.
My question is whether the UV energy emitted will potentially cause
harm to the viewer's eyes.  If so, will an ordinary piece of glass block
the UV emissions?  How thick should it be?
-------------------------
Jeff,

Ordinary window glass is not very transparent to UV light. On the other hand,
viewing the spark discharges from a Jacob's Ladder is not likely to be all 
that
harmful if the exposure is relatively brief. Actually, there is a greater
danger posed to one's vision from a full day outdoors on a clear sunny day.

Regards,
ProfHoff
=========================================================