The word plummet means to fall quickly, or plunge. It implies falling through the air at a great speed.
An airplane with no engine power would not be able to continue flying and would surely plummet to the ground.
The hot ashes from the fireworks display came plummeting to Earth as the people sitting on the ground gathered their things and ran for cover.
The word plummet can also refer to an item that weighs something else down. In this case, it is sometimes called a plumb bob and refers to a piece of lead at the end of a line.
Fisherman have made use of a plummet, or plumb bob, for centuries. It is a useful tool that helps determine the depth of the water.
We might be able to use a plummet to determine how far down the clog is in the bathtub drain.
The word sink means to drop or fall slowly to a lower place. Sink infers that the falling object or person is displacing a substance and is submerged, or under the surface. Sink can also mean to fall slowly due to weakness.
Watch out! If you step in that mud your feet will sink, and it will be almost impossible to pull yourself out!
Sink can also refer to the metal or ceramic tub that is used in a kitchen or bathroom. It typically has running water and serves as an area to place or wash dirty dishes and hands.
The sink is full of dirty dishes and no one is washing them! Everyone lets them pile up until there is no room left.
Collect all the dirty cups and dishes from your room and put them in the sink, please. I will wash them once we've gathered them all.