Far Away Things Look Small

Most things in the sky are very very far away from us.
Let me introduce you to this little cardboard person, Elvin.

Show the cardboard cutout personYou can make up any names you want.

[If you have the other figure hidden:]
This person has a little cardboard friend, Sherbin—let me go get Sherbin for you.

Will one of you hold Elvin, while I go get Sherbin?

[Have one of the children or a parent hold Elvin
while you walk away to get Sherbin where it is hidden.
Then, standing at a distance, hold up Sherbin and call out….]

Do they look the same size to you? [No.]

Who is bigger, Elvin or Sherbin? [Elvin, of course.]

OK, let’s have them meet each other.

Walk back to the group and hold the two cutouts next to each other side-by-side, then face-to-face.

Which is bigger, Elvin or Sherbin?

[They are the same size!]

So, what happened here? Did Sherbin magically grow up really fast?

[No, Sherbin only looked small when far away.]

This activity can also be done starting out with the two cardboard cutouts together, and not bothering to hide the second cutout figure. In that case, you would verify that “Elvin” and “Sherbin” are the same size at the outset and then have a volunteer walk about 10 meters away with Sherbin. You would then ask which looked bigger, Elvin or Sherbin. [Elvin.] And ask why Sherbin seemed to shrink. You can also ask them:
“Hold up your fingers and show me how big Sherbin looks now. Now show me how big Elvin looks. Let’s see if they are still the same size when Sherbin comes back”
and have the volunteer come back to the group to verify they are still exactly the same size.

So, now we know that the farther away something is, the smaller it looks.
Raise your hand if you’ve ever seen the full Moon.
Hold your fingers up and show me how big the Moon looks in the sky.

Is the Moon really that big? [No.]

How big is it really?

[Hold hands as far apart as you can.]

It’s bigger than this; bigger than this whole room;
bigger than your entire town or city; bigger than our whole state!

Now let’s go into the planetarium and see what our pretend sky looks like.