dry erase boards and non dry erase markers

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From: dave barker (dbarker_sfusd@yahoo.com)
Date: Mon Jul 15 2002 - 19:04:54 PDT 

Message-ID: <20020716020454.3980.qmail@web20009.mail.yahoo.com>
Date: Mon, 15 Jul 2002 19:04:54 -0700 (PDT)
From: dave barker <dbarker_sfusd@yahoo.com>
Subject: dry erase boards and non dry erase markers

Hi Everyone,

The other day, while teaching summer school in a class
other than mine, I began writing on the dry erase
board with chart paper markers. When I went to erase
it, it obviously didn't come off. After the kids and I
laughed about it, some of the students suggested that
if I trace over the writing with a dry erase marker,
and then erase it, it will come off. I tried it and it
worked! It was pretty cool!

My question is, why does this work? I'm hypothesising
that it has something to do with the properties of
both the non dry erase markers and the dry erase
markers adhereing to each other, and, after tracing
over it, the eraser lifts off the top coat (the dry
erase) and the dry erase lifts off the bottom coat
(the non dry erase). How could I turn this into a
science lesson for eighth graders?

I am teaching math this summer, but I know this will
probably happen next year with my eighth grade science
class at my regular school, and it would be fun, when
this happens, to turn it into a science lesson.

Again, how could I turn this into a science lesson,
covering molecules, adhesion, bonding, properties,
etc.? Any ideas? Thanks.

Dave Barker.

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