Scale Model of the Earth and Moon

scale_earth_moonAs well as the scale model of the solar system in my previous post, I will be using a scale model of the Earth and Moon in order to show distances, as well as demonstrate eclipses.   For this model, I used a 1″ wood ball, and a 1/4″ wood ball.  I drilled holes in them, and glued them onto bamboo Shish Kabob skewers.

Then I painted the moon a gray that my wife had in her craft paints, and  also painted the ‘Earth’ to vaguely resemble a globe.  I can’t say that I’m an artist.  If I work really hard, I may someday be good enough to be fired from a sweatshop operation in China.

To use this I’ll be using a pair of spring clamps, and a yardstick (or reasonable approximation thereof).  The proper distance between the Earth and Moon at this scale turns out to be 30 inches.

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Scale Model of the Solar System

At Fremont Peak Observatory this Saturday, I will be doing an activity for the kids that involves a large scale model of the solar system.  We’re not going to do the entire solar system, just some of the inner planets.

I really wanted to make the scale model of the Solar System as outlined in “Worlds of the Solar System” activity on the NASA Night Sky Network, but the materials for it turned out to be much more difficult to obtain than I anticipated.

You can in fact order ‘Dylite’ (a.k.a. ‘Smoothfoam’) balls in various sizes… if you are willing to order multiple units.  I don’t want twelve of the  1 & 3/8 inch balls, I want two!  The local crafting store has a very limited selection of these.  I could get the 4-inch ball but not the 3 & 7/8 inch one.  Plus, they’re expensive!

So, a different solution needed to be found.

Being pressed for time, and unable to find the materials, I resorted to rendering the model in 2D instead of 3D.   In the PDF file is a handout page with correctly scaled pictures of the planets (Mercury, Venus, Earth, Mars, Saturn, Jupiter, Uranus, Neptune).  Dwarf planets need not apply, apparently, but they are too small to be made in this 2D model anyway.

In order to accomplish my project, I printed two copies of the handout page in color.  I then used a glue stick to glue the back of the planets (before I cut them out) and pasted each sheet onto cardstock (a file-folder would work here too).  After letting them dry for a while, I then used scissors and a craft knife to cut out the pictures.

At this point, I had two pictures of each planet.  I quickly learned in the next step that the smallest planets (Mercury and Mars) are too small to do this next step.  The larger planets worked fine, and the larger rocky planets (Earth and Venus) could go either way .

The next step is to glue the two pictures of each planet together around bamboo Shish Kabob skewers (which I stole from the drawer in our kitchen).  For this step I recommend using ordinary white glue.  It wouldn’t work on regular weight paper, but on the cardstock it softened it up enough to mold the cardstock around the skewers.  This works great for the gas giant planets.

When I got down to Venus and Earth, however, it was much more difficult because of the small sizes of the circles.  When I got down to Mars, it was impossible.  I resorted to using a single cut-out, and placing a drop of glue on the back, then laying the tapered tip of the skewer into the glue.   I repeated this for Mercury.

In retrospect, this would work well for Venus and Earth as well.  If you wanted to, there is really no reason why the planets have to be double-sided, it just seemed like a good idea at the time.

I used the label page printed on plain paper, and glued the labels around the skewers using a glue stick.

I’m actually fairly proud of the result.

Happy IYA Eve!

2009 is the International Year of Astronomy, celebrating 400 years since Galileo first turned his telescope to the sky.   The IYA 2009 is a global initiative by the International Astronomical Union and the United Nations Educational, Scientific and Cultural Organization (UNESCO) to help the citizens of the world rediscover their place in the Universe through the day- and night-time sky.

A series of global events is planned, some in real life, some on the web.   2009 is the year to get out and discover the universe!

I’ll be participating in the 365 Days of Astronomy podcast (February 13).  If you’re an amateur astronomer, this is just one of they ways you can get involved.   Other ways include Project Astro, or volunteering to provide astronomy related resources to local schools.   Here in California astronomy is taught in the 5th grade, so start calling the schools in your area and asking the teachers if they’d like you to get involved.

I’ve been doing classroom talks for almost three years now (Since January 2007) and I’ve found them to be fun, and the kids to be attentive and involved, and found the teachers to be gateful. Be prepared to be asked questions like “What would happen if you fell into a black hole?”  (the single most common question I’ve ever gotten either in classrooms or at Fremont Peak).

One of the changes here will be the addition of a ‘resources’ page where some of the material I’ve used in classrooms will be posted, as well as a link to my 365 Days of Astronomy podcast episode (my first ever podcast…woot!) and transcript.

So remember, the Universe is yours to discover in 2009!

Beyond Belief

No, this isn’t a statement about religion or spirituality, it’s a statement about how to communicate astronomy to the public, but more importantly how *not* to communicate astronomy to the public.

In the September 2008 issue of  “Communicating Astronomy to the Public” astrophysicist Wallace Tucker tackles the too-frequent use of the word ‘believe’.    You can read his opinion piece online here [PDF].

I admit that I am guilty of using this word too often: i.e., “Astronomers believe there are as many as three black holes lurking in the Andromeda galaxy.”  Here are the problems: It communicates an unwarranted uncertainty, and it borders on the definition of ‘faith’.   Tucker points out that the word is used as shorthand for “Based on the evidence at hand, this is what most scientists think is going on, and there is no good evidence to indicate  otherwise.”  This is the same kind of disconnect that surrounds the word ‘theory’: In scientific circles it means something completely different than it means to the public.

I’ve often used ‘think’ for the same kind of shorthand, and while it removes the ‘faith’ aspect, it still communicates an unwarranted uncertainty.   It is far better to use something like   “The evidence indicates…” rather than ‘believe’ or ‘think’.

Precision is essential in preventing confusion.

Big Solar Flare

5th grade students at Rod Kelley will recall my talking about solar flares yesterday.  Here is a news report about an X-Class solar flare that was detected on December 5th.  Solar flares are classified as A, B, C, M or X depending on how much power they carry. It is sort of like the ‘Richter Scale’ for solar flares.  This solar flare was an X9, which is a very big one, one of the strongest solar flares recorded over the last 30 years.