Object: Any optical illusion. such as two lines drawn like this (lines are drawn here in the book version only) Notice that the lines are the same length, but arrows on the ends make the bottom line look longer.

Good morning, boys and girls. I wonder why I always say "good morning?" Maybe some Sunday I should say BAD SUNDAY, boys and girls. No, regardless of the weather or anything else it is always good to be in God’s house.

Look at what I have here this morning. (Show them the optical illusion and ask them questions about it, such as which line is the longest? How can you tell? Would you like to measure them with a ruler - or whatever is appropriate to reveal that…