Ice Cutting Experiment

What passes through a block of ice more quickly, copper wire or fishing line?

[keithbarkwood]

A good housemate doesn't talk loudly while recording videos at one in the morning.

[Daaninator]

Can't wait to get bullied when I explain this in a snowfight

[holocaust_.]

Judging by your eyes, you clearly need sleep.

[veritasium]

looks like a parabola, doesn't it? I haven't really thought about it so I'm not sure.

[veritasium]

@jonkuh haha so you had to commit to an answer before seeing what happened. Studies have shown that demonstrations with predictions are much more effective for learning.

[galerius]

After I learned about this as a kid, I loved slowly pushing my straw through ice cubes in the drinks at restaurants until I had carved a hole through the ice.

[hola-lwbi]

I like the way you have set up your videos. First starting with a question and then allowing the audience to participate.

[ansik_]

"But wait! Regelation isn't useless, you can make snowballs with it!"

[veritasium]

@ParbelleCondorcet Excellent work! I think I was using 30 gauge wire. It did take some hours for the wire to pass through. Also I'm told the pressure effect works mainly above -3C so I hope it's not too cold where you are.

[veritasium]

@tuto193 Um, I don't think the drink "filters" through the glass. The glass is just quite cold so water vapor from the air condenses onto it, making it wet.

[VincentParbelle]

Hi Derek! We're currently experimenting on this with copper/steel/nylon.
We had a block of ice roughly the same size as that you used in this video.
The steel wire, with two 5-kg weights attached, crossed the block in 10 minutes in the classroom. The experiment could be repeated in front of many groups. ...

[kiq]

Love the videos ! Before you did the experiment, I DID think about the thermal conductivity of copper but couldn't guess which one was going to slide through faster... OK, so...

I was looking at regelation in Wikipedia and noticed this...

"

Misconceptions

Ice skating is given as an example of regelation; however the pressure required is much greater than the weight of a skater. Additionally, regelation does not explain how one can ice skate at sub-zero (°C) temperatures.[4]


Weights suspended from a wire which cuts through ice, is an example given in old textbooks. Once again the pressure required far exceeds the force applied. Conduction of heat from the room through the metal wire is the correct explanation of this phenomenon.


Compaction and creation of snow balls is another example from old texts. Again the pressure required is far greater than can be applied by hand. A counter example is that cars do not melt snow as they run over it.

"So what gives ?

Then again, in the Wikipedia "TALK" portion, it says...

"The article contradicts itself: according to the introduction, a copper
wire cutting through ice is a valid example, although the details are
complex. According to the 'misconceptions' paragraph it is an invalid
example.
"

I also noticed in one of the comments here where he/she mentions the thickness of the fishing line vs. the thickness of the copper and thinking it should go quicker maybe ?

[DangerCloseE]

why were you talking like someone was trying to sleep?

[gore]

What if the copper wire that isn't in the ice is acting as a heatsink?

[matteloht]

2:33 Doesn't someone else find it kind of funny and ironic, that he demonstrates the effect of regelation by pressing a snowball, while the perfect real life example of that phenomenon literally slides past him in the background?

[TraeKryzer]

with the snowball i had always thought it was just because my bare hands melted the snow then it refroze when it got to the cold outside air

[miguelchacon]

2:43 i have never touched or seen snow in my life ;-;

[scottgauer]

When you stripped off the insulation, you decreased the thickness of the copper wire- thus less area was in contact with the ice and since you have the same weight that lead to higher pressure on the ice and faster melting.

[whisper__]

I mean they were going roughly the same speed. Then you scraped the enamel off, decreased the surface area and put the copper wire on. Drastically increasing the pressure, and suddenly it raced past the fishing line? Surely that is to be expected

[AndrewBoktor]

A cool thing to note is how the wire forms a perfect arc, which is the shape that distributes the downforce equally on the whole length :).