This month in Physics we are talking about…
Year 9 – Specific Heat Capacity
At the end of a sunny summer day at the beach you will notice that while the sand is very hot, sea water is still cool.
This happens since sand has a Specific Heat Capacity (S.H.C) of 830J/kgoC, meaning that with 830J of heat energy gained from the sun, the temperature of 1kg of sand increases by 1oC.
On the other hand, sea water needs far more energy to heat up as it has a S.H.C. of 3850J/kgoC!
In brief, the S.H.C. of material shows the amount of energy required to heat up 1kg of that material by 1oC. In the following video, you can see how the SHC of aluminium can be determined.
Year 10 – Conservation of Momentum
A rugby player running with the ball has a large momentum.
Momentum depends on the mass and velocity of the player.
When the player hits an opponent, most of the time we assume that the total momentum of both players before the collision is equal to the total momentum after the collision.
This results from the law of conservation of momentum that suggests that:
‘For two or more bodies in an isolated system acting upon each other, their total momentum remains constant unless an external force is applied’.
In the following video, you can see how the law of conservation of momentum is verified.