Zusammenfassung der Ressource
Energy Basics P1 2.1 - 2.4
- Forms of energy
- Chemical Energy
- Stored in fuel (including food)
- Released when chemical reactions take place
- Kinetic Energy
- Energy of a moving object
- Gravitational potential energy
- The energy of an object due to it's
position. Affected by gravity, height and mass
- Elastic potential energy
- The energy stored in a sprringy object
when we stretch or squash it
- Can be transferred from one form to another
- E.g. a torch
- The battery pushes a current through the bulb making the torch bulb
emit light and it also gets hot. We can show the energy transfers using a
flow diagram
- E.g. an falling block
- Has gravitational energy
- Transferred to kinetic as it falls and speeds up
- Transferred into heat and sound when it
hits the ground
- Conservation of energy
- Scientists have found that the
total energy after a transfer is
the same as the energy before
the transfer
- This is known as the conservation of energy
- It tells us that energy cannot be created nor destroyed
- Useful energy
- Many things use energy such as machines
but energy is wasted. It is not 100% effecient
- In a washing machine the friction between the
moving parts causes some of them to heat up. This is
wasted energy
- Useful Energy
- The energy transferred to where it is wanted,
in the form it is wanted
- Wasted Energy
- Energy that is not usefully transferred
- Spreading out
- Wasted energy is dissipated to the surroundings
- Useful energy eventually transfers to the surroundings too
- E.g. tyres
- Energy becomes less useful, the more it dissipates
- Energy and efficiency
- Weight is measured in newtons (N). THe weight of a
1kg object on the Earth's surface is about 10N
- Energy is measured in joules (J). The energy needed to lift a weight of 1N by a height of metre
- Sankey Diagrams
- Used to represent effeciency
- Efficiency = (Useful energy transferred by the device /
total energy supplied the the device) x 100%
- Improving efficiency
- Efficiency can be imrpoved in a number of
ways depending on the source of the
energy waste. This can save money and
time.
- e.g. friction between the moving pasts
causes heating -> Lubricate the moving
parts to reduce friction