Energy and heat
How is energy transferred as heat and work, and how does it change matter?
16 lessons
Lessons
Force, work and temperature
Chapter 1Force as a measure of interaction and weight $G = mg$Why does an astronaut weigh only one sixth as much on the Moon as on Earth, even though no part of the astronaut has gone missing?
- Chapter 2Work and energy
Why is carrying a heavy backpack along a level corridor not work in the physics sense, even though your shoulders get tired?
- Chapter 3Thermodynamic system, state variables and temperature
Why does a bicycle tyre feel harder on a hot summer day than on a frosty day, even though no more air has been pumped into it?
- Chapter 4Determining absolute zero
Why can the lowest possible temperature be found in a school laboratory, even though a thermometer does not come anywhere near it?
Pressure, heat and phases
Chapter 5Pressure and hydrostatic pressureWhy is the wall of a dam much thicker at the bottom than at the top, even though the water pressing on it is the same water all the way down?
- Chapter 6Internal energy, heat and conservation of energy
Why does a bicycle pump get hot when you pump up a tyre, even though nothing is heating the pump?
- Chapter 7Heating and cooling of matter: $Q = cm\Delta T$
Why does the sand on a beach burn your feet already in the late morning, when the water is still cool, even though the Sun has shone on both for the same time?
- Chapter 8Changes of state
Why does the temperature of boiling water not rise above $100\,{}^\circ\text{C}$, even though the hob is on full and energy keeps flowing into the pan?
- Chapter 9Thermal balance during a change of state
Why do ice cubes cool a drink so effectively, even though the ice itself is only at zero degrees? And why can some ice be left at the bottom of the glass, even though the drink was at room temperature?
Expansion and gases
Chapter 10Thermal expansionWhy is there a comb-shaped steel joint at the end of a long bridge, which makes the car tyres thump as they cross it?
- Chapter 11Changes of state of a gas and Boyle's law
Why does a sealed bag of crisps swell up tight on an aeroplane, even though nothing has been added to it?
- Chapter 12Ideal gas law $pV = nRT$
Why is a helium balloon much lighter than an air balloon of the same size? Does it contain less gas?
- Chapter 13Work done by a gas and the heat engine
Why does a thermal power plant get less than half of the energy of its fuel as electricity, and where does the rest of the energy go?
Energy and the environment
Chapter 14Energy production and the efficiency of power plantsWhy does a power plant need about two and a half times as much fuel as the electricity it produces, and how can the rest of the energy be put to use?
- Chapter 15Heat transfer, energy balance and climate change
Why is the mean temperature of the Earth about $+15\,{}^\circ\text{C}$ and not below freezing, even though the Earth radiates as much energy into space as it absorbs from the Sun?
- Chapter 16Applied lesson: heat phenomena in everyday life
Why does the ice pack in a cool bag keep drinks cold for hours in hot weather, but once the ice has melted, the drinks warm up quickly?
Apply independently
At the end of the module you can try whether you can apply what you have learned independently, in the style of the matriculation examination. The model answers and marking guides open after your own solution.
- Apply independently 3 tasks · 45 points
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Module goals
Show all 4 goals
The student
- deepens their understanding of energy as a central concept of physics
- can investigate phenomena related to the thermodynamic state of matter and to changes of state
- can apply the concepts and models of thermodynamics when examining energy production solutions and building a sustainable future
- recognises the importance of energy balance and heat transfer in climate change