Eli5: why are the tips of scissors worse at cutting than the base?
In: 38
Near the base the blades will be extremely close and well fitted to each other. As you move down the scissor toward the tip, you’re further from the bolt holding them together, and there’s more likely to be a little bit of separation between the blades.
When the blades are very close you’re applying force to a relatively small number of strands of cellulose. If the blades have separation, the paper can twist and you end up applying tensile force rather than shear. In doing so you significantly increase the number of strands you’re applying force to at the same time.
In theory you could manipulate a pair of scissors to be poorly fitter near the base and very well fitted toward the top and you should notice the opposite. You’ll notice the same if you simply grab a sheet between the thumb and index finger of each hand with the fingers very close together in attempt to tear, vs fingers far apart to pull.
The fewer strands you’re applying force to simultaneously, the better you’ll be able to break/separate the strands (cut).
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