Show them this website and ask them if they can figure out what it is all about:
This site shows the exact opposite side of the earth from anywhere on earth. So if you dug a hole straight down through the center of the earth, this site shows you were you would end up. Every student in my class had heard the old saying about “dig a hole to China”, where it is believed that if you dug a hole straight through the earth, you would end up in China. Apparently it’s not true, you would end up in the middle of the Atlantic. Students will definitely ask you to find where you would need to start digging if you wanted to end up in China (Argentina).
That is about all you need to pose the question “If you were to dig a hole to China, how deep would the hole be?”
I give the students the circumference of the earth. This lesson is teaching them to find the radius from the circumference.
C = 2(pi)r
At the end of class come back to the fact that if you give them radius, they would be able to give you diameter and circumference. If you give them circumference, they should be able to give you radius and diameter.
I do not give any handouts.