Science Electricity Study Notes:
PP1: Static Electricity:
Atomic structure:
- Protons and neutrons are in the nucleus (the core) and the electrons orbit the nucleus.
- Protons; positive charge
- Electrons; negative charge
- Neutrons; neutral charge (no charge)
- Opposite charges attract each other (negative to positive)
- LIke charges repel each other (positive to positive OR negative to negative).
- Atoms themselves have no overall charge as the number of protons and electrons balance
each other out, which makes that object neutral.
Formation of ions (atoms with a charge):
- Electrons can get rubbed off an atom.
- By removing the electric charge (electron) the atom now has more positive charges
(protons), so it becomes a positively charged ion.
- Loose electrons can be picked up by other atoms, the atom that picks up/ gains the lost
electron will form a negatively charged ion- as it has gained negative charge.
Static electricity:
- Static electricity is when there is an imbalance between negative and positive charges in an
object causing these electric charges to build-up on the surface, until they are released or
discharged.
- Static charge will ‘leak’ away overtime into the surroundings (including air).
- If the build-up of charge continues, the electrons may jump back from a negative surface to
a positive surface and release all their energy at once.
- The energy is converted into heat, light, sound and kinetic energy, observed as a spark or
lightning bolt.
- A lightning bolt happens when static charge builds up within the atmosphere and then
jumps to Earth, a building or another cloud.
Examples:
- if you rub your shoe on the carpet, your body collects extra electrons. The electrons cling to
your body until they can be released. If you touch someone, they will then get an electric
shock.
- As you remove your hat from your head, electrons are transferred from your hat to your
hair. Because your hairs now have the same charge, they repel each other and your hair will
stand on end, as your hairs are trying to get as far away from each other as possible.
- When you rub a balloon against your clothes it sticks to the wall. This is because you are
adding electrons (negative charges) to the surface of the balloon. Now the wall is more
positively charged than the balloon. As the wall and the balloon come in contact, the balloon
will stick because of the rule that opposites attract (positive and negative).
- When a balloon is rubbed on hair electrons are moved from the hair to the surface of the
balloon. The electrons then ‘stick’ to the balloon where the balloon was rubbed and do not
move across the surface of the balloon. The balloon becomes negatively charged (more
, electrons) and the person’s hair becomes positively charged (fewer electrons than before).
When you touch the negatively charged balloon to a natural (balanced) balloon, some of the
added electrons transfer to the neutral balloon. Now both balloons have a negative charge.
The balloons now push apart because likes repel each other (negative and negative).
PP2: Electric Current:
- The electricity from batteries and power points is made up of electrons movie along a wire
(kinetic energy) and can be transformed into other (more useful) forms.
- An electric circuit is a path that electrons travel around to deliver their energy.
- Circuits require: an energy source (battery, generator, dynamo) supplying the electrons with
energy. An energy user (light globe, heating element) which converts the energy of the
electrons. Wires to make the circuit complete.
- If the current is too strong in circuit a fuse will break which will protect the wiring if
something goes wrong. It stops the flow of excessive currents.
- The thicker the fuse the longer it will take for the fuse to heat up meaning that it would take
a long time to blow the fuse of the fuse wouldn’t blow at all.
- Any break in a circuit stops the flow of electrons and stops them delivering their energy
- As electrons move around a circuit, they lose nearly all of their energy as it is transformed
into other forms.
PP3: Measuring electricity:
- Electric current is measured in amperes/ amps (A). It measures the amount of charge that
flows through every second. Must be wired in a series circuit.
- Voltage; the amount of energy supplied to charges by a voltage source (V). Parallel to a
component
Resistance:
- Reduces current flow e.g. wires.
- Conductors have low resistance
- Insulators have high resistance
- The longer and the thicker the wire the more resistance
Series circuits:
- One path for the charges to flow
- One switch (turns it all off or on)
- If something in the circuit breaks e.g. a bulb then the circuit is incomplete and won’t work
- If you add more bulbs less voltage will reach each bulb and they will dim
Parallel circuits:
- Have branches/ junctions
- There is more than one way that the current can flow along
- Switches can be placed on each branch and con control its components individually
- If a bulb breaks only the bulbs on the same branch are affected
- If more bulbs are added in a parallel arrangement the brightness won’t change
PP1: Static Electricity:
Atomic structure:
- Protons and neutrons are in the nucleus (the core) and the electrons orbit the nucleus.
- Protons; positive charge
- Electrons; negative charge
- Neutrons; neutral charge (no charge)
- Opposite charges attract each other (negative to positive)
- LIke charges repel each other (positive to positive OR negative to negative).
- Atoms themselves have no overall charge as the number of protons and electrons balance
each other out, which makes that object neutral.
Formation of ions (atoms with a charge):
- Electrons can get rubbed off an atom.
- By removing the electric charge (electron) the atom now has more positive charges
(protons), so it becomes a positively charged ion.
- Loose electrons can be picked up by other atoms, the atom that picks up/ gains the lost
electron will form a negatively charged ion- as it has gained negative charge.
Static electricity:
- Static electricity is when there is an imbalance between negative and positive charges in an
object causing these electric charges to build-up on the surface, until they are released or
discharged.
- Static charge will ‘leak’ away overtime into the surroundings (including air).
- If the build-up of charge continues, the electrons may jump back from a negative surface to
a positive surface and release all their energy at once.
- The energy is converted into heat, light, sound and kinetic energy, observed as a spark or
lightning bolt.
- A lightning bolt happens when static charge builds up within the atmosphere and then
jumps to Earth, a building or another cloud.
Examples:
- if you rub your shoe on the carpet, your body collects extra electrons. The electrons cling to
your body until they can be released. If you touch someone, they will then get an electric
shock.
- As you remove your hat from your head, electrons are transferred from your hat to your
hair. Because your hairs now have the same charge, they repel each other and your hair will
stand on end, as your hairs are trying to get as far away from each other as possible.
- When you rub a balloon against your clothes it sticks to the wall. This is because you are
adding electrons (negative charges) to the surface of the balloon. Now the wall is more
positively charged than the balloon. As the wall and the balloon come in contact, the balloon
will stick because of the rule that opposites attract (positive and negative).
- When a balloon is rubbed on hair electrons are moved from the hair to the surface of the
balloon. The electrons then ‘stick’ to the balloon where the balloon was rubbed and do not
move across the surface of the balloon. The balloon becomes negatively charged (more
, electrons) and the person’s hair becomes positively charged (fewer electrons than before).
When you touch the negatively charged balloon to a natural (balanced) balloon, some of the
added electrons transfer to the neutral balloon. Now both balloons have a negative charge.
The balloons now push apart because likes repel each other (negative and negative).
PP2: Electric Current:
- The electricity from batteries and power points is made up of electrons movie along a wire
(kinetic energy) and can be transformed into other (more useful) forms.
- An electric circuit is a path that electrons travel around to deliver their energy.
- Circuits require: an energy source (battery, generator, dynamo) supplying the electrons with
energy. An energy user (light globe, heating element) which converts the energy of the
electrons. Wires to make the circuit complete.
- If the current is too strong in circuit a fuse will break which will protect the wiring if
something goes wrong. It stops the flow of excessive currents.
- The thicker the fuse the longer it will take for the fuse to heat up meaning that it would take
a long time to blow the fuse of the fuse wouldn’t blow at all.
- Any break in a circuit stops the flow of electrons and stops them delivering their energy
- As electrons move around a circuit, they lose nearly all of their energy as it is transformed
into other forms.
PP3: Measuring electricity:
- Electric current is measured in amperes/ amps (A). It measures the amount of charge that
flows through every second. Must be wired in a series circuit.
- Voltage; the amount of energy supplied to charges by a voltage source (V). Parallel to a
component
Resistance:
- Reduces current flow e.g. wires.
- Conductors have low resistance
- Insulators have high resistance
- The longer and the thicker the wire the more resistance
Series circuits:
- One path for the charges to flow
- One switch (turns it all off or on)
- If something in the circuit breaks e.g. a bulb then the circuit is incomplete and won’t work
- If you add more bulbs less voltage will reach each bulb and they will dim
Parallel circuits:
- Have branches/ junctions
- There is more than one way that the current can flow along
- Switches can be placed on each branch and con control its components individually
- If a bulb breaks only the bulbs on the same branch are affected
- If more bulbs are added in a parallel arrangement the brightness won’t change
