I just read this in the book Raising Freethinkers, and just had to share it.
The size of our universe is an incredibly hard things for most adults to understand... so how can you easily explain it to your child?
Next time you're in the sandbox, pick up a single grain of sand. Explain to your child that that piece of sand is the Sun, and the rest of the sand is how many other stars - like our sun, are in the Milky Way.
Now, just run your fingers through all of those stars in our own galaxy.
Then, take it a step further. Now, pretend that the whole Milky Way galaxy is one grain of sand. The rest of the sandbox represent how many galaxies are in the universe.
Now, run your fingers through all of those galaxies in our universe.
To be more accurate, the sandbox should be a 20-foot circle, and the sand should be 1 foot deep. Either way, this fun little explination of the solar system & universe is sure to be a hit!