Does a rock use up energy to maintain its shape?
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A rock sitting on land, the ocean floor, or floating in space maintains its shape somehow. Gravity isn't keeping it together because it is too small, so I'm assuming it is chemical or nuclear bonds keeping it together as a solid. If not it would simply crumble apart. So, what type of energy maintains the shape of a rock, where did this energy come from, and is it slowly dissipating?
As a corollary, if a large rock is placed on top of a small rock, is the energy required to maintain the shape of the small rock 'used' at a greater rate?
energy condensed-matter energy-conservation matter
add a comment |
up vote
14
down vote
favorite
A rock sitting on land, the ocean floor, or floating in space maintains its shape somehow. Gravity isn't keeping it together because it is too small, so I'm assuming it is chemical or nuclear bonds keeping it together as a solid. If not it would simply crumble apart. So, what type of energy maintains the shape of a rock, where did this energy come from, and is it slowly dissipating?
As a corollary, if a large rock is placed on top of a small rock, is the energy required to maintain the shape of the small rock 'used' at a greater rate?
energy condensed-matter energy-conservation matter
1
Closely related: physics.stackexchange.com/questions/1984/…
– dmckee♦
2 days ago
@dmckee, that's actually the analogy I used on a Worldbuilding question which, after thinking about things, prompted this question. Thanks for the link.
– CramerTV
2 days ago
add a comment |
up vote
14
down vote
favorite
up vote
14
down vote
favorite
A rock sitting on land, the ocean floor, or floating in space maintains its shape somehow. Gravity isn't keeping it together because it is too small, so I'm assuming it is chemical or nuclear bonds keeping it together as a solid. If not it would simply crumble apart. So, what type of energy maintains the shape of a rock, where did this energy come from, and is it slowly dissipating?
As a corollary, if a large rock is placed on top of a small rock, is the energy required to maintain the shape of the small rock 'used' at a greater rate?
energy condensed-matter energy-conservation matter
A rock sitting on land, the ocean floor, or floating in space maintains its shape somehow. Gravity isn't keeping it together because it is too small, so I'm assuming it is chemical or nuclear bonds keeping it together as a solid. If not it would simply crumble apart. So, what type of energy maintains the shape of a rock, where did this energy come from, and is it slowly dissipating?
As a corollary, if a large rock is placed on top of a small rock, is the energy required to maintain the shape of the small rock 'used' at a greater rate?
energy condensed-matter energy-conservation matter
energy condensed-matter energy-conservation matter
edited 2 days ago
knzhou
38.7k9106188
38.7k9106188
asked 2 days ago
CramerTV
538413
538413
1
Closely related: physics.stackexchange.com/questions/1984/…
– dmckee♦
2 days ago
@dmckee, that's actually the analogy I used on a Worldbuilding question which, after thinking about things, prompted this question. Thanks for the link.
– CramerTV
2 days ago
add a comment |
1
Closely related: physics.stackexchange.com/questions/1984/…
– dmckee♦
2 days ago
@dmckee, that's actually the analogy I used on a Worldbuilding question which, after thinking about things, prompted this question. Thanks for the link.
– CramerTV
2 days ago
1
1
Closely related: physics.stackexchange.com/questions/1984/…
– dmckee♦
2 days ago
Closely related: physics.stackexchange.com/questions/1984/…
– dmckee♦
2 days ago
@dmckee, that's actually the analogy I used on a Worldbuilding question which, after thinking about things, prompted this question. Thanks for the link.
– CramerTV
2 days ago
@dmckee, that's actually the analogy I used on a Worldbuilding question which, after thinking about things, prompted this question. Thanks for the link.
– CramerTV
2 days ago
add a comment |
4 Answers
4
active
oldest
votes
up vote
30
down vote
No, the exact opposite is true.
The molecules in a rock don't stay together because they're spending energy. They stay together because of attractive chemical bonds. The molecules have lower energy when they're together than when they're not, so you have to spend energy to break the rock apart, not to keep it together.
1
From where does the energy come for the chemical bonds? Isn't "attractive chemical bonds" an exchange of electrons? Is this exchange lossless?
– CramerTV
2 days ago
11
Where does the energy come from to roll downhill? There's an absolute potential energy at the bottom of the hill. Why doesn't it just roll uphill after a while sitting at the bottom when the energy runs out?
– William Grobman
2 days ago
5
I'm not being snarky either. This is an exact analogy using gravity and macro matter contours instead of electric forces and bond shapes.
– William Grobman
2 days ago
3
@CramerTV A chemical bond doesn't consist of firing electrons back and forth. It's simply the fact that electrons have some energy when they're bonded, and some energy when they're not, and the former is lower.
– knzhou
yesterday
add a comment |
up vote
4
down vote
There are various mechanisms that keep solid things together, they all have one thing in common: They reduce energy to a minimum! When you want to break it apart, it costs you energy to do so!
Examples of bonds are:
Hydrogen-Bonds, which are very weak and come from an asymmetry of the electron around the proton, in such a way that it is energetically favourable to form bonds instead of repel each other.
Ion-bonds, which can be quite strong, but the materials are often recalcitrant (brittle). Materials having ion-bonds are not pure, they are a mixture of two different elements, one positively charged, another negatively charged and they form molecules together, mainly due to the Coulomb force.
There are many more!
add a comment |
up vote
4
down vote
The amount of work done is equal to the distance moved times the force in the direction of motion. As the rock is staying the same shape it does not need to exert energy.
You may be thinking that the rock needs to expend energy in order to hold up its heavy mass in the same way our muscles do if we hold up a heavy weight. But muscles need to contract to lift a heavy weight and this requires continuous activity at the cellular level as explained in the answer to this question.
add a comment |
up vote
1
down vote
Consider an answer by contradiction:
Imagine the rock is in the vacuum of outer space with no energy able to be added to it.
Suppose it does use energy to maintain shape. Then at some point, it will run out of energy and the shape will change. Now, since it is out of energy and can't change shape, isn't it now maintaining shape without energy?
add a comment |
4 Answers
4
active
oldest
votes
4 Answers
4
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
30
down vote
No, the exact opposite is true.
The molecules in a rock don't stay together because they're spending energy. They stay together because of attractive chemical bonds. The molecules have lower energy when they're together than when they're not, so you have to spend energy to break the rock apart, not to keep it together.
1
From where does the energy come for the chemical bonds? Isn't "attractive chemical bonds" an exchange of electrons? Is this exchange lossless?
– CramerTV
2 days ago
11
Where does the energy come from to roll downhill? There's an absolute potential energy at the bottom of the hill. Why doesn't it just roll uphill after a while sitting at the bottom when the energy runs out?
– William Grobman
2 days ago
5
I'm not being snarky either. This is an exact analogy using gravity and macro matter contours instead of electric forces and bond shapes.
– William Grobman
2 days ago
3
@CramerTV A chemical bond doesn't consist of firing electrons back and forth. It's simply the fact that electrons have some energy when they're bonded, and some energy when they're not, and the former is lower.
– knzhou
yesterday
add a comment |
up vote
30
down vote
No, the exact opposite is true.
The molecules in a rock don't stay together because they're spending energy. They stay together because of attractive chemical bonds. The molecules have lower energy when they're together than when they're not, so you have to spend energy to break the rock apart, not to keep it together.
1
From where does the energy come for the chemical bonds? Isn't "attractive chemical bonds" an exchange of electrons? Is this exchange lossless?
– CramerTV
2 days ago
11
Where does the energy come from to roll downhill? There's an absolute potential energy at the bottom of the hill. Why doesn't it just roll uphill after a while sitting at the bottom when the energy runs out?
– William Grobman
2 days ago
5
I'm not being snarky either. This is an exact analogy using gravity and macro matter contours instead of electric forces and bond shapes.
– William Grobman
2 days ago
3
@CramerTV A chemical bond doesn't consist of firing electrons back and forth. It's simply the fact that electrons have some energy when they're bonded, and some energy when they're not, and the former is lower.
– knzhou
yesterday
add a comment |
up vote
30
down vote
up vote
30
down vote
No, the exact opposite is true.
The molecules in a rock don't stay together because they're spending energy. They stay together because of attractive chemical bonds. The molecules have lower energy when they're together than when they're not, so you have to spend energy to break the rock apart, not to keep it together.
No, the exact opposite is true.
The molecules in a rock don't stay together because they're spending energy. They stay together because of attractive chemical bonds. The molecules have lower energy when they're together than when they're not, so you have to spend energy to break the rock apart, not to keep it together.
answered 2 days ago
knzhou
38.7k9106188
38.7k9106188
1
From where does the energy come for the chemical bonds? Isn't "attractive chemical bonds" an exchange of electrons? Is this exchange lossless?
– CramerTV
2 days ago
11
Where does the energy come from to roll downhill? There's an absolute potential energy at the bottom of the hill. Why doesn't it just roll uphill after a while sitting at the bottom when the energy runs out?
– William Grobman
2 days ago
5
I'm not being snarky either. This is an exact analogy using gravity and macro matter contours instead of electric forces and bond shapes.
– William Grobman
2 days ago
3
@CramerTV A chemical bond doesn't consist of firing electrons back and forth. It's simply the fact that electrons have some energy when they're bonded, and some energy when they're not, and the former is lower.
– knzhou
yesterday
add a comment |
1
From where does the energy come for the chemical bonds? Isn't "attractive chemical bonds" an exchange of electrons? Is this exchange lossless?
– CramerTV
2 days ago
11
Where does the energy come from to roll downhill? There's an absolute potential energy at the bottom of the hill. Why doesn't it just roll uphill after a while sitting at the bottom when the energy runs out?
– William Grobman
2 days ago
5
I'm not being snarky either. This is an exact analogy using gravity and macro matter contours instead of electric forces and bond shapes.
– William Grobman
2 days ago
3
@CramerTV A chemical bond doesn't consist of firing electrons back and forth. It's simply the fact that electrons have some energy when they're bonded, and some energy when they're not, and the former is lower.
– knzhou
yesterday
1
1
From where does the energy come for the chemical bonds? Isn't "attractive chemical bonds" an exchange of electrons? Is this exchange lossless?
– CramerTV
2 days ago
From where does the energy come for the chemical bonds? Isn't "attractive chemical bonds" an exchange of electrons? Is this exchange lossless?
– CramerTV
2 days ago
11
11
Where does the energy come from to roll downhill? There's an absolute potential energy at the bottom of the hill. Why doesn't it just roll uphill after a while sitting at the bottom when the energy runs out?
– William Grobman
2 days ago
Where does the energy come from to roll downhill? There's an absolute potential energy at the bottom of the hill. Why doesn't it just roll uphill after a while sitting at the bottom when the energy runs out?
– William Grobman
2 days ago
5
5
I'm not being snarky either. This is an exact analogy using gravity and macro matter contours instead of electric forces and bond shapes.
– William Grobman
2 days ago
I'm not being snarky either. This is an exact analogy using gravity and macro matter contours instead of electric forces and bond shapes.
– William Grobman
2 days ago
3
3
@CramerTV A chemical bond doesn't consist of firing electrons back and forth. It's simply the fact that electrons have some energy when they're bonded, and some energy when they're not, and the former is lower.
– knzhou
yesterday
@CramerTV A chemical bond doesn't consist of firing electrons back and forth. It's simply the fact that electrons have some energy when they're bonded, and some energy when they're not, and the former is lower.
– knzhou
yesterday
add a comment |
up vote
4
down vote
There are various mechanisms that keep solid things together, they all have one thing in common: They reduce energy to a minimum! When you want to break it apart, it costs you energy to do so!
Examples of bonds are:
Hydrogen-Bonds, which are very weak and come from an asymmetry of the electron around the proton, in such a way that it is energetically favourable to form bonds instead of repel each other.
Ion-bonds, which can be quite strong, but the materials are often recalcitrant (brittle). Materials having ion-bonds are not pure, they are a mixture of two different elements, one positively charged, another negatively charged and they form molecules together, mainly due to the Coulomb force.
There are many more!
add a comment |
up vote
4
down vote
There are various mechanisms that keep solid things together, they all have one thing in common: They reduce energy to a minimum! When you want to break it apart, it costs you energy to do so!
Examples of bonds are:
Hydrogen-Bonds, which are very weak and come from an asymmetry of the electron around the proton, in such a way that it is energetically favourable to form bonds instead of repel each other.
Ion-bonds, which can be quite strong, but the materials are often recalcitrant (brittle). Materials having ion-bonds are not pure, they are a mixture of two different elements, one positively charged, another negatively charged and they form molecules together, mainly due to the Coulomb force.
There are many more!
add a comment |
up vote
4
down vote
up vote
4
down vote
There are various mechanisms that keep solid things together, they all have one thing in common: They reduce energy to a minimum! When you want to break it apart, it costs you energy to do so!
Examples of bonds are:
Hydrogen-Bonds, which are very weak and come from an asymmetry of the electron around the proton, in such a way that it is energetically favourable to form bonds instead of repel each other.
Ion-bonds, which can be quite strong, but the materials are often recalcitrant (brittle). Materials having ion-bonds are not pure, they are a mixture of two different elements, one positively charged, another negatively charged and they form molecules together, mainly due to the Coulomb force.
There are many more!
There are various mechanisms that keep solid things together, they all have one thing in common: They reduce energy to a minimum! When you want to break it apart, it costs you energy to do so!
Examples of bonds are:
Hydrogen-Bonds, which are very weak and come from an asymmetry of the electron around the proton, in such a way that it is energetically favourable to form bonds instead of repel each other.
Ion-bonds, which can be quite strong, but the materials are often recalcitrant (brittle). Materials having ion-bonds are not pure, they are a mixture of two different elements, one positively charged, another negatively charged and they form molecules together, mainly due to the Coulomb force.
There are many more!
answered 2 days ago
kalle
16311
16311
add a comment |
add a comment |
up vote
4
down vote
The amount of work done is equal to the distance moved times the force in the direction of motion. As the rock is staying the same shape it does not need to exert energy.
You may be thinking that the rock needs to expend energy in order to hold up its heavy mass in the same way our muscles do if we hold up a heavy weight. But muscles need to contract to lift a heavy weight and this requires continuous activity at the cellular level as explained in the answer to this question.
add a comment |
up vote
4
down vote
The amount of work done is equal to the distance moved times the force in the direction of motion. As the rock is staying the same shape it does not need to exert energy.
You may be thinking that the rock needs to expend energy in order to hold up its heavy mass in the same way our muscles do if we hold up a heavy weight. But muscles need to contract to lift a heavy weight and this requires continuous activity at the cellular level as explained in the answer to this question.
add a comment |
up vote
4
down vote
up vote
4
down vote
The amount of work done is equal to the distance moved times the force in the direction of motion. As the rock is staying the same shape it does not need to exert energy.
You may be thinking that the rock needs to expend energy in order to hold up its heavy mass in the same way our muscles do if we hold up a heavy weight. But muscles need to contract to lift a heavy weight and this requires continuous activity at the cellular level as explained in the answer to this question.
The amount of work done is equal to the distance moved times the force in the direction of motion. As the rock is staying the same shape it does not need to exert energy.
You may be thinking that the rock needs to expend energy in order to hold up its heavy mass in the same way our muscles do if we hold up a heavy weight. But muscles need to contract to lift a heavy weight and this requires continuous activity at the cellular level as explained in the answer to this question.
answered yesterday
Virgo
1,7011925
1,7011925
add a comment |
add a comment |
up vote
1
down vote
Consider an answer by contradiction:
Imagine the rock is in the vacuum of outer space with no energy able to be added to it.
Suppose it does use energy to maintain shape. Then at some point, it will run out of energy and the shape will change. Now, since it is out of energy and can't change shape, isn't it now maintaining shape without energy?
add a comment |
up vote
1
down vote
Consider an answer by contradiction:
Imagine the rock is in the vacuum of outer space with no energy able to be added to it.
Suppose it does use energy to maintain shape. Then at some point, it will run out of energy and the shape will change. Now, since it is out of energy and can't change shape, isn't it now maintaining shape without energy?
add a comment |
up vote
1
down vote
up vote
1
down vote
Consider an answer by contradiction:
Imagine the rock is in the vacuum of outer space with no energy able to be added to it.
Suppose it does use energy to maintain shape. Then at some point, it will run out of energy and the shape will change. Now, since it is out of energy and can't change shape, isn't it now maintaining shape without energy?
Consider an answer by contradiction:
Imagine the rock is in the vacuum of outer space with no energy able to be added to it.
Suppose it does use energy to maintain shape. Then at some point, it will run out of energy and the shape will change. Now, since it is out of energy and can't change shape, isn't it now maintaining shape without energy?
answered 2 days ago
lamplamp
393317
393317
add a comment |
add a comment |
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1
Closely related: physics.stackexchange.com/questions/1984/…
– dmckee♦
2 days ago
@dmckee, that's actually the analogy I used on a Worldbuilding question which, after thinking about things, prompted this question. Thanks for the link.
– CramerTV
2 days ago