Zusammenfassung der Ressource
Particles
- Heat Transfer
- Conduction
- In Solids Only
- Occurs when particles are
exposed to heat energy, causing
them to vibrate and warm up
- Metals are some of the best conductors
because they have a sea of electrons,
which are free to move.
- When it is heated, the electrons gain
energy that is then transfred throughout
the metal
- Insulators such as plastics and wood,
don;t have this sea of electrons, so they
are worse conductors.
- Convection
- Heat transfers from Warmer to Cooler areas.
- So, Cooler (dense) fluids sink
through warmer (less dense)
fluids.
- This creates Convection Currents
- This happens when a Liquid or a Gas is
heated, but then cools in a continuous cycle.
- In Liquids and Gases
- Radiation
- Anything Emits or
Absorbs Radiation
- Matt and Black surfaces
Absorb and Radiate the
Most
- Shiny and Light surfaces Absorb
and Radiate the Least
- Objects with a large
surface area Absorb
and Radiate more
- U Values measure how good an
insulator is.
- The LOWER the value the BETTER
insulator it is.
Anmerkungen:
- U values really show how good it is at transfering heat, that its why a lower value is better when looking at how good an insulator a material is/
- Evaporation
- Water takes away energy from your
body. This is why puddles dry up on cold
days
- The faster (more energetic) molecules leave first, later
followed by the cooler ones.
- Energy Equations
- Specific Heat Capacity
- Usually in J/kg °C
- The amount of energy (measured in joules)
needed to change the temperature of 1kg of the
material by 1°C.
- Energy Transfered
- m x c x T = E
- Mass of Object x Specific Heat Capacity x
Change in temperature of the object.
- p x t = E
- Power x Time
- Energy Efficency
- Useful Energy (Output)/Total Energy (Input)
- Watt Hours
- Watts x Hours
- Usually in kWh
- Electricity bill "Units" are in kWh
- Simply x by price per unit to get electricity cost
- Kinetic Theory
- Matter is anything made out of atoms and molecules.
- The 3 states of Matter are Solids, Liquids, and Gases
- As particles heat up,
they gain Kinetic Energy
- This causes the particles to move and
spread out, causing a change of state.