It’s a beautiful day for a picnic in the park with momma and daddy. As the family sits down to eat, Luna accidentally sends her orange rolling down hill. She races after it, but isn’t able to get to it in time and it ends up in the lake. Jupiter tries to knock it back to shore with one of his grapes, but to their surprise, the grape sinks! How can a little grape sink, when a much bigger and heavier orange floats? What’s happening here? During make believe, the gang soon learns that whether something can float or sink doesn’t necessarily have to do with how big it is or how heavy it is.