Will there be any change in water level/height of floating part of the boat if stones are dropped into the pond from a floating boat?
The weight of the water displaced by the hull of a floating boat equals the total weight of the boat and its contents. This is called "Archimedes Principle", and is true of any object floating in any fluid.
If stones are removed from the boat, it becomes lighter and displaces less water. That
means it rises up so that less of its volume is below the surface. The change in the submerged volume of the boat equals the volume of water weighing the same as the stones removed.
If, for example, 2.2 pounds (about 1 kg) of stones are removed, that is the weight of about one liter of water. The boat would rise until 1 liter, or 1000 cubic centimeters, less of its hull's volume remained below the water line.
Paul Walorski, B.A., Part-time Physics/Astronomy Instructor
If something is submerged in water, it will displace an amount of water equal to its volume. If something is floating in water, it will displace an amount of water equal to its weight. Therefore, if you have anything more dense than water (stones) floating in a boat and you throw it into the water, the water level will go down because the object displaces less water when submerged.
Eric Newman, B.S.
'The strength and weakness of physicists is that we believe in what we can measure. And if we can't measure it, then we say it probably doesn't exist. And that closes us off to an enormous amount of phenomena that we may not be able to measure because they only happened once. For example, the Big Bang. ... That's one reason why they scoffed at higher dimensions for so many years. Now we realize that there's no alternative... '