This series of slides discusses the basics of sunscreens including their history, types,
mechanism for blocking UV light (absorption), appearance (due to scattering) and
challenges to providing effective protection. The final slide asks students to use what
they’ve learned to answer the three driving questions for the unit.
Slide 14 includes an optional demo that shows how selective absorption of UV light by
certain chemicals used in printing money is serves as an anti-counterfeiting measure. If
you choose to do this demo you will need:
• One or more UV lights of any size (several options are available from Educational
Innovations at www.teachersource.com)
• Different kinds of paper currency (these must be relatively recently printed; Euros
and Canadian bills work particularly well)