Thermal physics
1. Celcius to Kelvin
T(K)=T(C)+273,15
2. 2 forms of internal energy
Kinetic energy and potential energy
3. Liquid at 40 is cooled to 25 explain what happens to internal e.
The kinetic energy of particles decrease and the potential energy remains the same
4. Why Pyrex, with a small c.l.e than regular glass is less susceptible to this than regular
glass
Pyrex has a small c.l.e meaning that a large change in temp will result in only a small
contraction. This will cause much thermal stress in the glass, making it much less likely to
crack
5. Peg needs to fit on whole(slightly larger)
Peg needs to be colder than the block so when peg heats back up to normal temp. It will
expand against the sides of the hole, ensuring a tight fit
6. Explain why you should never pour cold water onto a frying pan just used
This would cause a vary rapid decr in temp, and thus contraction on some parts of the pan,
whilst the rest of the pan would still be hot, resulting in thermal stresses and possible
damage e.g. cracking or warping
-basic formula
-mercury only have liquid( so divide volume coeff by 3 to get length coeff)
7. Explain the nb of expansion of water of pond upon freezing to plant and animal life
8. Copper wire bent into large ring (gap 1mm wide at 20C ) possible close gap by
cooling?
No. Gap in the ring behaves as if it were filled with copper. Cooling the ring will decrease the
size of the gap, but no amount of cooling will result in this imaginary copper completely
disappearing
1. Celcius to Kelvin
T(K)=T(C)+273,15
2. 2 forms of internal energy
Kinetic energy and potential energy
3. Liquid at 40 is cooled to 25 explain what happens to internal e.
The kinetic energy of particles decrease and the potential energy remains the same
4. Why Pyrex, with a small c.l.e than regular glass is less susceptible to this than regular
glass
Pyrex has a small c.l.e meaning that a large change in temp will result in only a small
contraction. This will cause much thermal stress in the glass, making it much less likely to
crack
5. Peg needs to fit on whole(slightly larger)
Peg needs to be colder than the block so when peg heats back up to normal temp. It will
expand against the sides of the hole, ensuring a tight fit
6. Explain why you should never pour cold water onto a frying pan just used
This would cause a vary rapid decr in temp, and thus contraction on some parts of the pan,
whilst the rest of the pan would still be hot, resulting in thermal stresses and possible
damage e.g. cracking or warping
-basic formula
-mercury only have liquid( so divide volume coeff by 3 to get length coeff)
7. Explain the nb of expansion of water of pond upon freezing to plant and animal life
8. Copper wire bent into large ring (gap 1mm wide at 20C ) possible close gap by
cooling?
No. Gap in the ring behaves as if it were filled with copper. Cooling the ring will decrease the
size of the gap, but no amount of cooling will result in this imaginary copper completely
disappearing
