Etrog v Lemon

What is the difference between an etrog and a lemon?  Ask any child in the Shemesh class and he or she can tell you.  An etrog is almost all pith and no meaty pulp.  You cannot make etrog juice like you can with a lemon.  The etrog has many more seeds than a lemon.  At circle Liz cut both the lemon and the etrog in half and the children smelled, touched and saw the differences.  On Monday we will plant the seeds of the lemon and the etrog and hope for some growth.  Wish us luck.  We will keep you posted.