Earth Day Birthday Celbration?

At 8:15 this morning I challenged the second grade class to tell me what Earth Day was for...
No one really had an idea, so I shared my theory with them. In 1970 Earth Day was created. That is a fact. I believe that just after my 2nd birthday the Earth was so happy that I was born that it had to celebrate. Thus the reason for Earth Day. The earth so loved me it created the holiday.
... I don't think they bought into my idea. But did they learn what Earth Day is all about?