Have you ever wondered how we get water from a well? Learn about it with this DIY!
If you drop a bucket into a pool of water, you might be surprised to see it floating instead of sinking. This happens because of a property called buoyancy! Buoyancy is a floating force. It’s what lets a boat made out of concrete and metal stay above the water instead of sinking like concrete and metal would normally do.
When an object is placed into water, like a bucket in a well, it pushes some of the water out of its way. The water doesn’t like being displaced, so it pushes back on the object. The force it pushes back with (that’s buoyancy!) is equal to the weight of the water that got displaced by the object. So if your bucket displaces one gallon of water, the water will push up on the bucket with a force as strong as the weight of that gallon (about 8 pounds). If the bucket weighs less than 8 pounds, it’ll float. If it weighs more than 8 pounds, it’ll sink.
Buckets, boats, and other hollow things have a buoyancy advantage because they’re filled with air. Air is much lighter than water. A gallon-sized hunk of solid metal is definitely heavier than a gallon of water, but a gallon-sized bucket, with most of that volume taken up by air, will be lighter than a gallon of water. In order for a bucket to sink, you need to put something heavy in it to counteract the buoyant force. Try it out with your own well and bucket!