Why do many kitchen knife handles, spatula handles, and electric kettle handles have convex and conc

Kitchen knife handle. Spatula handles. The handle of the kettle has a convex and concave pattern. Roughen the contact surface.

This is a theory about the nature of friction after the concave and convex meshing theory. It was first proposed by the English scholar de Sazolius in 1734. He believed that the friction of two metals with a very bright surface would increase, which could be explained by the increase in the molecular gravitational force of two objects when their surfaces were in full contact.

Since the beginning of the last century, with the development of industry and technology, the study of friction theory has been further deepened, and by the middle of the last century, a new friction adhesion theory was born.

The new triboadhesion theory holds that two surfaces in contact with each other, no matter how smooth they are, are rough at the atomic scale, with many tiny protrusions, and that when the two surfaces are put together, the tops of the micro-protrusions are in contact, and there is a gap of 10 -8 m or more between the contact surfaces other than the micro-protrusions.

In this way, the slightly raised top of the contact is subjected to the normal pressure on the contact surface. If this pressure is small, the slightly raised top undergoes elastic deformation; If the normal pressure is large, exceeding a certain value (about a few thousandths of a newton on each protrusion), exceeding the elastic limit of the material, the top of the micro-bulge will undergo plastic deformation and be pressed into a flat top, and the distance between the two objects in contact with each other will become smaller to the range of molecular (atomic) gravity, so that the two pressed contact surfaces will have an atomic bond. In this case, in order for two surfaces in contact with each other to slide relative to each other, a tangential force must be applied to one of the surfaces to overcome the gravitational pull between the molecules (atoms) and cut the contact formed by the actual contact area, which creates friction.

Through continuous experimentation and analysis, it is found that the mechanisms proposed by the above two theories can produce friction, and the mechanism proposed by the adhesion theory is more common than that of the meshing theory. However, in different materials, the performance of two mechanisms is biased: metal materials, and the friction generated is mainly adhesion; For wood, the friction is mainly meshing; In fact, the nature of friction is still inconclusive and is still being discussed in depth.

Increase friction.

If not, I'm afraid you won't be able to save your feet.

This can increase friction, anti-slip, and prevent accidental injury.

Non-slip increases the contact area and prevents danger.

Increase friction and anti-slip to prevent hand slipping and accidentally injuring yourself.

It is used to prevent slipping, and if it is not easy to get rid of, it poses a danger.

This increases the friction between the hand and the shank, reducing the risk of accidental injuries caused by hand slippage.

This is to prevent slipping, and this sharp weapon will be injured by mistake.

It is used to prevent slipping, otherwise it is easy to hurt yourself.

Without a non-slip setting, the friction is minimal, and it is prone to danger.

It is used to prevent slipping, it is easy to fall off and hurt yourself.

In order to increase friction. Because the embossing pattern can reduce the slippage of some oils.

Those patterns are designed to increase friction between the hand and the handle, making it difficult for those to slip off.

The uneven pattern will cause the hand to rub and the force will not fall.

The main thing is to increase friction and prevent people from slipping when they grab the handle.

If there are no such bumpy patterns. If there is oil on your hands, it is easy to slip.

In order to prevent the handle from slipping, it is more stable to hold.

This allows you to hold the handle better.

Increase handle friction to prevent slipping.

The handle has a convex and concave pattern, which makes the contact surface rough and increases the friction.