She eats them in a wink. She has to catch them quickly, Or else the peanuts sink. Fern can give some good advice That slower ducks should note. Kids, here's how you can test Fern's theory for yourself. Add 6 teaspoons of table salt to the salt water cup and mix with a spoon for a few minutes.
Objects float if they're lighter than the amount of liquid that they displace, or push aside.
They sink if they're heavier. Fern's peanuts are heavier than the fresh water that they displace, so they sink. Dissolving salt in fresh water makes the same amount of liquid heavier, allowing the peanut to float.