Why do ducks float on water?
For grown-ups: the science
Ducks float because their bodies and feathers hold air, and water pushes up to hold them.
Floating depends on buoyancy: a duck displaces water, and the upward buoyant force can balance its weight. Ducks are relatively low-density because of air spaces, including lungs and air sacs, and their waterproofed, interlocking feathers trap air and reduce waterlogging. Webbed feet are primarily for propulsion, not flotation.
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Transcript
A duck is bobbing on a pond. How does it stay on top of the water?
A duck's body is light for its size, with air spaces inside. Water can hold it up instead of letting it sink.
Its feathers overlap like a raincoat and keep water away from its skin. The feathers trap extra air, which helps it float.
Wide webbed feet push water backward when the duck swims. That moves the duck forward while its body keeps bobbing.
So ducks float because their light, airy bodies push aside enough water to be held up. Their feathers help keep them dry, too.