Thursday, February 28, 2013

Lessons From My Childhood on How to Teach

One of the best parts of my job is getting to do outreach.  This is going out and teaching the public about the research that I do.  Since I love what I do and those that I encounter are usually interested in what I have to say or they wouldn't be there (like you wouldn't be reading this if you didn't want to), it is almost always a rewarding experience all around.  However, I had some childhood experiences with outreach that were, well, a little traumatic.  However, they have taught me lessons that I use every time I teach whether in the classroom, engaging the public at LIGO, or writing for you.


Ever since I was a young child, I've always known that where I am now is where I wanted to be.  That is, I've always known that I wanted to be a physicist or an astronomer.  Of course, that's not what I said; I wanted to be an astronaut since that is the hero job for the physical sciences.  My family has also been supportive of me and one of my favorite things to do was go to the planetarium.  At the time, I lived outside of Pittsburgh, PA and we would go to the Buhl Planetarium (before it became part of the newer Carnegie Science Center - the building is now part of the Children's Museum of Pittsburgh).

Front entrance of the Buhl Planetarium in Pittsburgh, PA. [Source: Wikipedia]

On the fateful trip in question, I was no more than 7 or 8 years old and I was watching a demonstration in between planetarium shows with my father.  The presenter asked for a volunteer from the crowd, preferably with long fine hair.  The next thing I felt is my father's hand on my back pushing me forward.  I wasn't interested in being the center of attention, but the presenter thought that I would be perfect for the role.

She called me forward and had me stand on a plastic milk crate beside a metal dome that was bigger than my head.  She told me that I was going to have to hold on the the metal dome with one hand but I was not to do a list of things or I would get hurt.  Then I was worried.  She had me put one hand on the dome and turned the machine on.  It made a lot noise and I feel an odd tingling over my skin.  Then I was scared.  The presenter was very happy about everything and told me to shake my head.  I did so timidly.  Then she encouraged me to shake my head with more vigor.  I shook the heck out of my head so she would leave me alone and I could be done with all of this.  Then EVERYONE who is watching this demonstration WAS LAUGHING AT ME.  Then they applauded as the machine was turned off and I was helped down from my perch and left to think I was being laughed at.

The machine with the big metal dome attached to the top.  I later discovered that this is a Van de Graaff generator.  [Source: UMN Physics department]

It wasn't until I was in middle school that I figured out why everyone was laughing at me.  That machine was a Van de Graaff generator and it deposited static electricity on me.  The warnings that worried me were to prevent me from getting "zapped" and everyone was laughing at me because my hair was standing on end.  The harder I shook my head, the more the static electricity made my hair stand out.  A lot like this:

WHAT WENT WRONG?:  The presenter didn't show me what I looked like in a mirror (as is featured in the clip above) or tell me what I looked like.  I had no idea why everyone was laughing at me or what the point of the "hair raising" demonstration was.  Without this knowledge, I walked away from the experience thinking that everyone was really laughing at ME and not the effects of static electricity.

LESSON LEARNED:  If you use a volunteer in a demonstration, make sure that they understand what is happening.

I don't have many occasions where I need a volunteer for a demonstration, but when I do I make the volunteer the focus of the demonstration so that, at the very least, they walk away understanding what happened. 

Read more about how Van de Graaff generators work.


When I was too young for school, I wanted to be a big girl and play school.  Even then I loved science.  One day I convinced my father to play school with me.  Using the sliding green chalk board doors on my toy box, my father taught me about the layers of the Earth.

A toy box much like the one my father used to play school with me.  [Source: It's Still Life blog]

The Earth's layers can be generalized into 4 main layers: the crust at the surface where we live, then the mantle, and finally the outer and inner cores.

Diagram showing the layers of the Earth.  [Source: About Earth blog]

I was told that the crust was very thin and the mantle is hot molten rock (magma) [note: only the mantle near the outer core is molten but the mantle under the crust is about 1000oF so I equated that to "molten" too as a child].  I'd seen documentaries about volcanoes on television and knew what "molten rock" meant.  This completely changed the way I saw the swing set in my back yard.  Why?  Well, have you noticed the divot under the swings where you drag your feet to slow the swing to a stop?  I saw that as eating away at the crust and I was afraid that I would break through to the mantle and sink my feet into molten rock!  I know that it really isn't logical since I'd seen deeper holes before and there was nothing but dirt at the bottom, but I was a little kid and didn't think like that.  Anyway, I then was afraid of breaking through the crust if I dragged my feet and I was too chicken to jump off.  That left me sitting on the swing waiting for it to slow down on its own.  The wait took a lot of the fun out of swinging!

WHAT WENT WRONG?:  The scale of "thick" and "thin" was not established.  When I heard that the crust was thin, I defined for myself what "thin" was.  I assumed it was only as deep as I could dig through it.  What "thin" really meant is compared to the size (radius) of the Earth.

For the record, the radius of the Earth is almost 4,000 miles and the crust is up to about 22 miles.  Since 22 miles is much, much less than 4,000 miles, the crust is indeed "thin" compared to the size of the Earth!

LESSON LEARNED:  When you tell someone that something is "big" or "small", make sure you establish what you are comparing that something to, i.e. make sure you set the scale for your comparison.

I sometimes tell this story after I admonish people to always ask a scientist how big or small they think "big" or "small" are.  I tell them that I think a "big" gravitational wave, one that we would only expect to see every 10 years or so, would change the length of LIGO's 4 km (2.5 mile) long arms less than 1/1000th the diameter of a proton (10-18 m).   That may be "big" to me now, but to a 5-year-old me something smaller than an atom would be most certainly be considered "small".