Displacement is the answer.
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As long as the rock is moved from the boat to the water in the same pool, The water level will not change.
'
Displacement is displacement
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The boat will sit higher with out the rock, But the level of the pool will remain the same.
'
Edit:
Proving wrong below, I am not smarter than a fifth grader. But I've learned something new and I see My error.
Density of pure water is 1. If the rock sinks it is more dense than water. For the sake of argument lets assume the rock has a volume of 1 (pick your own units) and a density of 1.1. Thus the rock weighs 1.1 times more than an equal volume of water, so it displaces a volume of water 1.1 times it's own volume while in the boat. Throw it in the water and it displaces it's own volume, so the level in the pool is now lower.
OK, instead of a boat, what if the rock was inside of a tube that is sealed on the bottom and open on the top. The tube is taller than the depth of the pool? With the rock in the tube it sits on the bottom. When the rock is moved outside of the tube to the bottom of the pool, what happens to the water level?
All the comments in this thread are exactly the sort to be expected
from a bunch of people that program uC's :-)
We just have to be nit pickers, it's required by what we do.
We have to think of every strange possibility or the systems we
create will fail.
BTW: Every time the guy in the boat exhales the water level is changed
because his weight decreases...from water vapor loss mainly.
The water level also changes a very tiny bit depending on the water
temperature....so what if the rock is glowing red hot? Also a red hot
rock would release a bit of steam into the air as it hit the surface..
My oldest daughter and I just did an experiment: and we have our answer. :-)
1 six inch plastic bowl filled 1/2 way with water = Pool
ALTOIDS Box (remove lid) = Boat
1/4 measuring cup = Man
10 marbles = rock used in test #1
15 quarters = rock used in test #2
Electrical tape = used to mark the levels on the plastic bowl ... and cover the holes on the ALTIODS Box where the lid attached.
Note: The 1/4 inch measuring cup was to keep the center of weight in the 'boat', otherwise the marbles would roll to one corner and sink the boat.
"So what was the answer ???" - really? I set the stage with enough common household items you could do the test for yourself to see, and then hypothesise the observed result in reverse. Ohh well, (See attached images)
"It would make a great science fair experiment (do schools even have science fairs anymore ?)." - That's a great idea, and yes some schools still have science fairs. Here at least, they are done through the local university mostly just to provide the space.
EDIT: The measuring cup (aka - the 'Man') was actually 1/3rd cup and not 1/4th cup
A snail climbs a 6 foot wall 3 feet each day but slips back 2 feet each night. Assuming the barber shaves everyone who does not shave himself/herself, how many were going to St. Ives?
A snail climbs a 6 foot wall 3 feet each day but slips back 2 feet each night. Assuming the barber shaves everyone who does not shave himself/herself, how many were going to St. Ives?
Comments
'
As long as the rock is moved from the boat to the water in the same pool, The water level will not change.
'
Displacement is displacement
'
The boat will sit higher with out the rock, But the level of the pool will remain the same.
'
Edit:
Proving wrong below, I am not smarter than a fifth grader. But I've learned something new and I see My error.
from a bunch of people that program uC's :-)
We just have to be nit pickers, it's required by what we do.
We have to think of every strange possibility or the systems we
create will fail.
BTW: Every time the guy in the boat exhales the water level is changed
because his weight decreases...from water vapor loss mainly.
The water level also changes a very tiny bit depending on the water
temperature....so what if the rock is glowing red hot? Also a red hot
rock would release a bit of steam into the air as it hit the surface..
Gotta pick those nits :-)
So what was the answer ???
It would make a great science fair experiment (do schools even have science fairs anymore ?).
Bean
You go girl!
LOL
"So what was the answer ???" - really? I set the stage with enough common household items you could do the test for yourself to see, and then hypothesise the observed result in reverse. Ohh well, (See attached images)
"It would make a great science fair experiment (do schools even have science fairs anymore ?)." - That's a great idea, and yes some schools still have science fairs. Here at least, they are done through the local university mostly just to provide the space.
EDIT: The measuring cup (aka - the 'Man') was actually 1/3rd cup and not 1/4th cup
So where did they bury the survivors?
A snail climbs a 6 foot wall 3 feet each day but slips back 2 feet each night. Assuming the barber shaves everyone who does not shave himself/herself, how many were going to St. Ives?
Exactly!!
But to find out who shaves & buries the survivors going to St. Ives, see http://www.mbeckler.org/resistor_grid/