Comparing Distances/Sizes

As kids we learned that the Sun was many miles away from the Earth.  Kids today learn this as well and many of them learn/memorize the Earth-Sun distance in miles.  The distance between the Earth and the Sun is 93 million miles.  That's a great distance, compared to common distances on the Earth itself, but how far away is 93 million miles?  Unless you have something to compare this distance to, 93 million miles is such a large number that it is almost but impossible to understand.  Telling a child that the distance from the Earth to the Sun is 93 million miles doesn't tell them much but that it's a long ways away.  This doesn't mean that you shouldn't teach your kid the distance, but it's also important to put this distance in perspective.

In my classes I have students go through a simple activity of scaling the size of the solar system down to the size of a school hallway using toilet paper.  This gives students a visual representation of how far each planet is from the Sun.  93 million miles may be a lot, but the distance from the Sun to Jupiter is much farther than this.  The NRAO in Green Bank, WV has a very cool scaled model of the solar system using the land itself.  They've taken the road from near the entrance of the facility down to the Green Bank Telescope and scaled it to the size of the solar system. 

Another cool scaling activity to introduce to kids/students is one originally found on the Astronomy Picture of the Day website.  This is an interactive activity that allows you to scale from very small sizes/distances to very large sizes/distances.  If you haven't seen this interactive activity, I highly encourage you to check it out.  It puts sizes in the Universe in perspective.