I had used the phrase “like a hot knife through butter” a good few times in my life before I came to ask what I think are some pretty fundamental questions that require clarification about this butter and knife.
- How hot is the knife?
- How sharp (or dull) is the knife?
- How cold is the butter?
- Is the butter frozen?
- Is the butter salted?
- Hypothetically, if the knife was infinitely hot, and the butter was infinitely cold, how would the interaction change?
If someone would like to dig a little deeper and find some research about these questions, I would love to see it. If you want to do experiments of your own, I can neither encourage nor discourage, for legal reasons. However, I would be willing to review the results, should any such experiments take place.
Overall, I think the goal would be to create a multi-dimensional graph showing the rate at which a knife passes through butter, with several of the attributes discussed above being plotted as variables.
When you have a sharp, pointy knife like the one in the picture, it doesn’t even need to be hot to go through butter.
If the butter is frozen solid, how hot would the knife have to be so that no force had to be applied to get the knife through the butter?
@ Steven,
As a certain Tom Foley can attest, I am no physicist, but I don’t think that the knife could move without any force required. Even if the very hot knife sunk into the butter under only its own weight, gravitational force would be in effect there.