Ducks

The family was all together at my father's house last weekend.  Kayla was standing on the grate to the floor heating register.  She started stamping on it, so I told her she was disturbing the people downstairs.  Travis asked if there really were people there, and I said "No, not really".  Then he asked what the register was. Travis has a scientific mind, so I explained that it's how the heat works in that house.  There are ducts under the floor to carry the heat from the furnace and out these registers.  He knows what ducts are, but obviously Kayla doesn't.  She first asked "Is there water down there?"  I didn't get it at first and said "No, why?"  She answered "For the ducks!"  You can bet I cracked up! 
Kayla started stamping again, and said "I'm bothering the ducks!"