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.

365 Days of Astronomy Podcasts

Here are the links to the last few days:

January 2nd: Jeff Setzer on using your first telescope

January 3rd: Emily Lakdawalla on 5 years of Spirit on Mars

January 4th: Dr. Pamela Gay and Fraiser Cain on Dark Matter and Dark Energy

January 5th: Doug Welch and Michael Koppleman from Slacker Astronomy on the seasons and Solar System Geometry

January 6th: Carolyn Collins Peterson (The Spacewriter) Top Ten reasons why stargazing is cool.

January 7th: Travis Searle, Rebecca Turner, Mike Simonsen from AAVSO on understanding variable stars.

January 8th: Stuart Lowe from the Jodcast on Pulsars