What mechanism at the microscopic level determines whether a system heats up or not?
When placed in an ordinary or a microwave oven, a beaker of water heats up except during boiling (i.e., a phase change involving latent heat). Now, suppose a system absorbs energy in such a way that the electrons are excited to higher energy levels. Will this necessarily heat up the system? In other words, is heating caused by the electrons or atoms in an object being excited to higher energy levels?
quantum-mechanics thermodynamics statistical-mechanics solid-state-physics phase-transition
edited 31 mins ago
Geoffrey
3,64911229
asked 5 hours ago
mithusengupta123
1,30811334
add a comment |
When placed in an ordinary or a microwave oven, a beaker of water heats up except during boiling (i.e., a phase change involving latent heat). Now, suppose a system absorbs energy in such a way that the electrons are excited to higher energy levels. Will this necessarily heat up the system? In other words, is heating caused by the electrons or atoms in an object being excited to higher energy levels?
quantum-mechanics thermodynamics statistical-mechanics solid-state-physics phase-transition
edited 31 mins ago
Geoffrey
3,64911229
asked 5 hours ago
mithusengupta123
1,30811334
add a comment |
When placed in an ordinary or a microwave oven, a beaker of water heats up except during boiling (i.e., a phase change involving latent heat). Now, suppose a system absorbs energy in such a way that the electrons are excited to higher energy levels. Will this necessarily heat up the system? In other words, is heating caused by the electrons or atoms in an object being excited to higher energy levels?
quantum-mechanics thermodynamics statistical-mechanics solid-state-physics phase-transition
edited 31 mins ago
Geoffrey
3,64911229
asked 5 hours ago
mithusengupta123
1,30811334
When placed in an ordinary or a microwave oven, a beaker of water heats up except during boiling (i.e., a phase change involving latent heat). Now, suppose a system absorbs energy in such a way that the electrons are excited to higher energy levels. Will this necessarily heat up the system? In other words, is heating caused by the electrons or atoms in an object being excited to higher energy levels?
quantum-mechanics thermodynamics statistical-mechanics solid-state-physics phase-transition
quantum-mechanics thermodynamics statistical-mechanics solid-state-physics phase-transition
edited 31 mins ago
Geoffrey
3,64911229
asked 5 hours ago
mithusengupta123
1,30811334
edited 31 mins ago
Geoffrey
3,64911229
asked 5 hours ago
mithusengupta123
1,30811334
edited 31 mins ago
Geoffrey
3,64911229
edited 31 mins ago
Geoffrey
3,64911229
edited 31 mins ago
Geoffrey
3,64911229
3,64911229
asked 5 hours ago
mithusengupta123
1,30811334
asked 5 hours ago
mithusengupta123
1,30811334
asked 5 hours ago
mithusengupta123
1,30811334
1,30811334
add a comment |
add a comment |
3 Answers
3
active
oldest
votes
On the case of a microwave oven the water molecules in the food are made to vibrate. Water molecules are tiny electric dipoles and these are made to vibrate more strongly. The molecules stay in the electronic ground state.
answered 4 hours ago
my2cts
4,4082617
What happens in ordinary ovens/burners? For heating to take place, a necessary condition is that the system must absorb energy. For this to happen, there must be a coupling between the environment that supplies energy and the system that absorbs it. For the microwave example, it is the electromagnetic microwave that couples to the dipole moment of water molecules.
– mithusengupta123
3 hours ago
The microwave photon energy level causes rotation not vibration of water dipole molecules. The vibration energy is higher than the microwave oven photon energy. For a good explanation of the interaction of radiation with matter, check out the Hyperphysics web site
– Bob D
3 hours ago
add a comment |
The microwave photon energy level gives rotational kinetic energy to water molecules due to interaction of the electromagnetic field with the water dipole molecule. The rotational kinetic energy is subsequently randomized to increase the average translational kinetic energy of the molecules, increasing the temperature of the water molecules. The microwave energy levels are well below those needed to excite electrons to higher levels.
A regular oven cooks with infrared electromagnetic energy. The photon energy level corresponds to molecular vibration. These energy levels are likewise too low for electron excitation.
Hope this helps
answered 2 hours ago
Bob D
1,992211
A toaster oven certainly uses radiation, but I'd argue that a bake-a-cake oven also uses conduction and convection.
– psitae
26 mins ago
add a comment |
The heat contained in a system can be thought of as the total kinetic energy of a system. my2cts' answer is correct, but I'll add that if you excite an electron to a higher energy level, that will indeed cause heating in many cases (see for example FRET).
The friction between the water molecules and the rest of the system is what causes things to heat up in a microwave. In a conventional oven, it's a direct transfer of kinetic energy from hot air.
Homework question: would something heat up in a microwave if it didn't contain any water?
answered 3 hours ago
psitae
613522
add a comment |
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3 Answers
3
active
oldest
votes
3 Answers
3
active
oldest
votes
active
oldest
votes
active
oldest
votes
On the case of a microwave oven the water molecules in the food are made to vibrate. Water molecules are tiny electric dipoles and these are made to vibrate more strongly. The molecules stay in the electronic ground state.
answered 4 hours ago
my2cts
4,4082617
What happens in ordinary ovens/burners? For heating to take place, a necessary condition is that the system must absorb energy. For this to happen, there must be a coupling between the environment that supplies energy and the system that absorbs it. For the microwave example, it is the electromagnetic microwave that couples to the dipole moment of water molecules.
– mithusengupta123
3 hours ago
The microwave photon energy level causes rotation not vibration of water dipole molecules. The vibration energy is higher than the microwave oven photon energy. For a good explanation of the interaction of radiation with matter, check out the Hyperphysics web site
– Bob D
3 hours ago
add a comment |
On the case of a microwave oven the water molecules in the food are made to vibrate. Water molecules are tiny electric dipoles and these are made to vibrate more strongly. The molecules stay in the electronic ground state.
answered 4 hours ago
my2cts
4,4082617
What happens in ordinary ovens/burners? For heating to take place, a necessary condition is that the system must absorb energy. For this to happen, there must be a coupling between the environment that supplies energy and the system that absorbs it. For the microwave example, it is the electromagnetic microwave that couples to the dipole moment of water molecules.
– mithusengupta123
3 hours ago
The microwave photon energy level causes rotation not vibration of water dipole molecules. The vibration energy is higher than the microwave oven photon energy. For a good explanation of the interaction of radiation with matter, check out the Hyperphysics web site
– Bob D
3 hours ago
add a comment |
On the case of a microwave oven the water molecules in the food are made to vibrate. Water molecules are tiny electric dipoles and these are made to vibrate more strongly. The molecules stay in the electronic ground state.
answered 4 hours ago
my2cts
4,4082617
On the case of a microwave oven the water molecules in the food are made to vibrate. Water molecules are tiny electric dipoles and these are made to vibrate more strongly. The molecules stay in the electronic ground state.
answered 4 hours ago
my2cts
4,4082617
edited 3 hours ago
answered 4 hours ago
my2cts
4,4082617
answered 4 hours ago
my2cts
4,4082617
answered 4 hours ago
my2cts
4,4082617
4,4082617
What happens in ordinary ovens/burners? For heating to take place, a necessary condition is that the system must absorb energy. For this to happen, there must be a coupling between the environment that supplies energy and the system that absorbs it. For the microwave example, it is the electromagnetic microwave that couples to the dipole moment of water molecules.
– mithusengupta123
3 hours ago
The microwave photon energy level causes rotation not vibration of water dipole molecules. The vibration energy is higher than the microwave oven photon energy. For a good explanation of the interaction of radiation with matter, check out the Hyperphysics web site
– Bob D
3 hours ago
add a comment |
What happens in ordinary ovens/burners? For heating to take place, a necessary condition is that the system must absorb energy. For this to happen, there must be a coupling between the environment that supplies energy and the system that absorbs it. For the microwave example, it is the electromagnetic microwave that couples to the dipole moment of water molecules.
– mithusengupta123
3 hours ago
The microwave photon energy level causes rotation not vibration of water dipole molecules. The vibration energy is higher than the microwave oven photon energy. For a good explanation of the interaction of radiation with matter, check out the Hyperphysics web site
– Bob D
3 hours ago
What happens in ordinary ovens/burners? For heating to take place, a necessary condition is that the system must absorb energy. For this to happen, there must be a coupling between the environment that supplies energy and the system that absorbs it. For the microwave example, it is the electromagnetic microwave that couples to the dipole moment of water molecules.
– mithusengupta123
3 hours ago
What happens in ordinary ovens/burners? For heating to take place, a necessary condition is that the system must absorb energy. For this to happen, there must be a coupling between the environment that supplies energy and the system that absorbs it. For the microwave example, it is the electromagnetic microwave that couples to the dipole moment of water molecules.
– mithusengupta123
3 hours ago
The microwave photon energy level causes rotation not vibration of water dipole molecules. The vibration energy is higher than the microwave oven photon energy. For a good explanation of the interaction of radiation with matter, check out the Hyperphysics web site
– Bob D
3 hours ago
The microwave photon energy level causes rotation not vibration of water dipole molecules. The vibration energy is higher than the microwave oven photon energy. For a good explanation of the interaction of radiation with matter, check out the Hyperphysics web site
– Bob D
3 hours ago
add a comment |
The microwave photon energy level gives rotational kinetic energy to water molecules due to interaction of the electromagnetic field with the water dipole molecule. The rotational kinetic energy is subsequently randomized to increase the average translational kinetic energy of the molecules, increasing the temperature of the water molecules. The microwave energy levels are well below those needed to excite electrons to higher levels.
A regular oven cooks with infrared electromagnetic energy. The photon energy level corresponds to molecular vibration. These energy levels are likewise too low for electron excitation.
Hope this helps
answered 2 hours ago
Bob D
1,992211
A toaster oven certainly uses radiation, but I'd argue that a bake-a-cake oven also uses conduction and convection.
– psitae
26 mins ago
add a comment |
The microwave photon energy level gives rotational kinetic energy to water molecules due to interaction of the electromagnetic field with the water dipole molecule. The rotational kinetic energy is subsequently randomized to increase the average translational kinetic energy of the molecules, increasing the temperature of the water molecules. The microwave energy levels are well below those needed to excite electrons to higher levels.
A regular oven cooks with infrared electromagnetic energy. The photon energy level corresponds to molecular vibration. These energy levels are likewise too low for electron excitation.
Hope this helps
answered 2 hours ago
Bob D
1,992211
A toaster oven certainly uses radiation, but I'd argue that a bake-a-cake oven also uses conduction and convection.
– psitae
26 mins ago
add a comment |
The microwave photon energy level gives rotational kinetic energy to water molecules due to interaction of the electromagnetic field with the water dipole molecule. The rotational kinetic energy is subsequently randomized to increase the average translational kinetic energy of the molecules, increasing the temperature of the water molecules. The microwave energy levels are well below those needed to excite electrons to higher levels.
A regular oven cooks with infrared electromagnetic energy. The photon energy level corresponds to molecular vibration. These energy levels are likewise too low for electron excitation.
Hope this helps
answered 2 hours ago
Bob D
1,992211
The microwave photon energy level gives rotational kinetic energy to water molecules due to interaction of the electromagnetic field with the water dipole molecule. The rotational kinetic energy is subsequently randomized to increase the average translational kinetic energy of the molecules, increasing the temperature of the water molecules. The microwave energy levels are well below those needed to excite electrons to higher levels.
A regular oven cooks with infrared electromagnetic energy. The photon energy level corresponds to molecular vibration. These energy levels are likewise too low for electron excitation.
Hope this helps
answered 2 hours ago
Bob D
1,992211
answered 2 hours ago
Bob D
1,992211
answered 2 hours ago
Bob D
1,992211
answered 2 hours ago
Bob D
1,992211
1,992211
A toaster oven certainly uses radiation, but I'd argue that a bake-a-cake oven also uses conduction and convection.
– psitae
26 mins ago
add a comment |
A toaster oven certainly uses radiation, but I'd argue that a bake-a-cake oven also uses conduction and convection.
– psitae
26 mins ago
A toaster oven certainly uses radiation, but I'd argue that a bake-a-cake oven also uses conduction and convection.
– psitae
26 mins ago
A toaster oven certainly uses radiation, but I'd argue that a bake-a-cake oven also uses conduction and convection.
– psitae
26 mins ago
add a comment |
The heat contained in a system can be thought of as the total kinetic energy of a system. my2cts' answer is correct, but I'll add that if you excite an electron to a higher energy level, that will indeed cause heating in many cases (see for example FRET).
The friction between the water molecules and the rest of the system is what causes things to heat up in a microwave. In a conventional oven, it's a direct transfer of kinetic energy from hot air.
Homework question: would something heat up in a microwave if it didn't contain any water?
answered 3 hours ago
psitae
613522
add a comment |
The heat contained in a system can be thought of as the total kinetic energy of a system. my2cts' answer is correct, but I'll add that if you excite an electron to a higher energy level, that will indeed cause heating in many cases (see for example FRET).
The friction between the water molecules and the rest of the system is what causes things to heat up in a microwave. In a conventional oven, it's a direct transfer of kinetic energy from hot air.
Homework question: would something heat up in a microwave if it didn't contain any water?
answered 3 hours ago
psitae
613522
add a comment |
The heat contained in a system can be thought of as the total kinetic energy of a system. my2cts' answer is correct, but I'll add that if you excite an electron to a higher energy level, that will indeed cause heating in many cases (see for example FRET).
The friction between the water molecules and the rest of the system is what causes things to heat up in a microwave. In a conventional oven, it's a direct transfer of kinetic energy from hot air.
Homework question: would something heat up in a microwave if it didn't contain any water?
answered 3 hours ago
psitae
613522
The heat contained in a system can be thought of as the total kinetic energy of a system. my2cts' answer is correct, but I'll add that if you excite an electron to a higher energy level, that will indeed cause heating in many cases (see for example FRET).
The friction between the water molecules and the rest of the system is what causes things to heat up in a microwave. In a conventional oven, it's a direct transfer of kinetic energy from hot air.
Homework question: would something heat up in a microwave if it didn't contain any water?
answered 3 hours ago
psitae
613522
answered 3 hours ago
psitae
613522
answered 3 hours ago
psitae
613522
answered 3 hours ago
psitae
613522
613522
add a comment |
add a comment |
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