Protect yourself from photo-chemical changes

This is for the ISOCS Senior Primary students, who are inquiring into changing materials. Some of you might be in the hight mountains, and others on warm sunny beaches, but in either case, we do not want any material changes due to photo-chemistry.

Uploaded by periodicvideos on Jan 3, 2012
The Professor - donning his clip-on shades - is at Bondi Beach in Australia for a discussion about sunscreen.