4 ms·
This is the famous Feynman method for gaining intuition of many physical problems: just set one of the variables to an absurdly huge number and see what happens
by enriquto 7y ago
This is the famous Feynman method for gaining intuition of many physical problems: just set one of the variables to an absurdly huge number and see what happens.
He illustrated it with the problem of what happens to the level of water on a pool when you throw overboard a stone from a floating boat. Does the water level rise or drop? Well, imagine that your small stone is made of neutron star material...
- deanCommie 7y agoI'm actually not finding this analogy helpful. Forgive me if I'm missing something obvious, I have a newborn and am underslept. I assume neutron star material is incredibly dense and so the rock would be unbelievably heavy. To the point that the mass would actually likely sink the boat, and then we can't throw the rock out. OK but let's assume that the boat is somehow massive enough to support the weight of the rock. Now we've changed the scale of the other variables of the experiment in proportion to the rock/neutron star, and we're back to ground zero, are we not?
- enriquto 7y agoA 1-ton neutron-star stone will be the size of a dust speck. When it is aboard, only its mass matters, and it will push the boat downwards and displace 1 ton of water. When it is at the bottom of the pool, only its volume matters, and it will displace a negligible amount of water.