ARTable

When I moved away from home to a new city at the age of 21, I had no real life skills. I knew how to make black tea (don't ask me about steep time, that'll be another blog someday when I have picked up tea as my next hyper fixation) and maggi. And honestly none of them were very good. One day I wanted to eat fried maggi because baby steps. So I purchased some onions and a 30 rupee serrated knife from the store. I didn't know what it mattered if it's serrated or not, I just found the cheapest thing and grabbed it. The next morning, my roommate bought some bread and some butter and I thought to myself, time to add another dish to my ever growing list of culinary prowess – buttered bread. Revolutionary, I know! I learnt so fast that serrated knives cannot double as butter knives. This led to a well set up rabbit hole dive into knife physics. Well, I don't know if that's the official name but that's what we're calling it.

When we think of a knife, the first visual that comes to mind is a stainless metal blade with one side tapered down to a sharp edge while the opposite side remains dull, ending in a handle made of wood, aluminum, titanium, bone, carbon fiber, stainless steel, resin, etc. Otherwise known as a regular kitchen knife. By definition, sharpness is the cutting ability of an edge. So, basically the sharper something is the better it is at cutting. So what does that mean to me? Jack {redacted}. So, down went the rabbit hole and I found a blog that explained sharpness in terms of force. And it made sense. Finer the point, higher the pressure – force per unit area. Extend the point linearly in one direction and you have the outline of an edge. So the same knife will apply more pressure on it's pointy side than the duller side. That means that sharpness depends on not just the edge thickness, but also the force applied to do the cutting, and the weight of the blade and the handle.

Once we have understood what makes a sharp knife, we need to understand what to do with it. Chop and slice are the 2 most basic things we do with a knife. And it all begins with a cut. A cut begins with a crack – the cutting edge of the blade makes a crack in the object you wish to cut. We then apply a force to drive the knife further down into the crack in the object. The edge concentrates this force due to its lower surface area and that's why you can slide down with a sharp knife easily while you'd have to put a lot more effort (force) trying to achieve the same with a duller knife.

Another thing to realise is that the cut that the knife's cutting edge makes is a smaller volume than what the non-cutting edge can fit into. This is why it's best when the taper to the cutting edge is really gradual in a knife as opposed to an axe, where your application requires more hacking than cutting. The thickness of the non cutting edge is also of interest. The taper has an optimal angle ranging from 17-22 degrees. This way you're not breaking the object along the initial cut line when your blade moves down beyond the cutting edge. You're using the rest of your blade to gently coax the two sides of the cut away from each other.

Another important factor is weight. Heavier your knife, less force you have to apply to achieve a similar result as with a lightweight knife. You can just let it slide down and thank Gravity for being just right on your home planet. However, a heavier knife will exhaust your wrists faster. So here comes something every idealist dreads – the tradeoff! Do we want a knife which will be easy on our shoulders and forearms or do we want easy on the wrist? Fortunately, finding a balance is possible.

Even though the physics of a perfect knife is absolute, the perfect knife might vary from person to person depending on their preferences, height of the person, height of the surface where they're cutting, posture, technique, objects they're cutting, a whole plethora of materials they might be biased towards. For example, for me the perfect knife to cut onions with is when the knife is in another person's hand and I'm nowhere near the kitchen.