A2 Unit G484: The Newtonian World Module 1: Newton’s laws and momentum • 4.1.1 Newton’s laws of motion • 4.1.2 Collisions Module 2: Circular motion and oscillations • 4.2.1 Circular motion • 4.2.2 Gravitational Fields • 4.2.3 Simple harmonic oscillations Module 3: Thermal Physics • 4.3.1 Solid, liquid and gas • 4.3.2 Temperature • 4.3.3 Thermal properties of materials

Module 3: Thermal Physics • 4.3.1 Solid, liquid and gas • 4.3.2 Temperature • 4.3.3 Thermal properties of materials

What is the difference between heat and temperature? Is there a maximum temperature?

4.3.2 Temperature You should be able to: Explain that thermal energy is transferred from a region of higher temperature to a region of lower temperature; (b) Explain that regions of equal temperature are in thermal equilibrium; (c) Describe how there is an absolute scale of temperature that does not depend on the property of any particular substance (ie the thermodynamic scale and the concept of absolute zero); (d) Convert temperatures measured in kelvin to degrees Celsius (or vice versa): T (K)= θ (°C) + 273.15; (e) State that absolute zero is the temperature at which a substance has minimum internal energy.

What unit is this? °C

°C What unit is this? The Celsius scale is an absolute scale. It is the absolute thermodynamic scale minus 273.15 exactly. Absolute scale/K Celsius Scale/oC Absolute zero -273.15 Triple point of water 273.16 0.01 Ice point 273.15 0.00 Steam point 373.15 100.00

Why did Einstein win a Nobel prize? Because of his work on the photoelectric effect and on kinetic theory.

The First Law of Thermodynamics Change in Internal Energy = Heat Transfer + Work Done ΔU = ΔQ + ΔW i.e. if you put energy into a system, its internal energy will increase

An Obvious Law of Thermodynamics Thermal energy is transferred from a region of higher temperature to a region of lower temperature.

The Zeroth Law of Thermodynamics B C If A is in equilibrium with B, and B is in equilibrium with C, then A and C must be in equilibrium.

Read pages 296-300 in APFY Complete questions 1,2,3 and 4 on page 305 The rms speed of the molecules in a gas is 600ms-1 and the mass of the molecules is 4.6 x 10-26 kg. What is the temperature of the gas in degrees Celsius? 127oC

4.3.3 Thermal properties of materials You should be able to: Define and apply the concept of specific heat capacity. (b) Select and apply the equation E = mcΔθ (c) Describe an electrical experiment to determine the specific heat capacity of a solid or a liquid. Describe what is meant by the terms latent heat of fusion and latent heat of vaporisation.

Specific Heat Capacity The specific heat capacity is the energy needed to raise the temperature of 1 kg by 1 K ΔU = m c Δθ change in = mass x specific heat x temperature internal energy capacity change

Calculating the specific heat capacity of a metal

Calculating the specific heat capacity of a metal mm= mass of metal [kg] = cm = s.h.c of the metal [J kg-1 K-1] = ? θm = initial temperature of the metal [K or oC] =  

Calculating the specific heat capacity of a metal mw= mass of water [kg] = cw = s.h.c of the water [J kg-1 K-1] = 4180 J kg-1 K-1 θw = initial temperature of the water [K or oC] =

Calculating the specific heat capacity of a metal Once in thermal equilibrium…   θf = final temperature of the water and metal =

Calculating the specific heat capacity of a metal Thermal energy lost by metal = mmcmΔθ   Thermal energy gained by water = mwcwΔθ θw final = θm final mmcmΔθ = mwcwΔθ cm = mwcw(θw final – θw initial) mm(θm initial – θm final)