Unit 04 Definitions
Raw materials are materials taken directly from nature that we process into other materials to make products with.
Paper is obtained by forming a paste that is mashed and then pressed and dried. Witch raw material does this paste came from?
Paper comes from wood.
Complete the following sentences:
Protons are ________ charged particles found in the _______ of the atom.
Neutrons have ______ charge and are found in the _______ of the atom.
Electrons are ________ charged particles that are found ________ of the atom.
Protons are positively charged particles found in the nucleus of the atom.
Neutrons have no charge and are found in the nucleus of the atom.
Electrons are negatively charged particles that are found moving in shells around the nucleus of the atom.
A translucent material lets light through but we cannot see through it.
How are the planks of wood that we use in the workshop called?
The wood that we use in the workshop is called plywood.
Cork is obtained from the bark of the cork oak.
Current: the amount of electrons flowing through a wire over a certain time. It is measured in Amps (A).
Using three light bulbs and cell, draw a circuit in series.
Circuit is drawn on the blackboard.
Complete the following sentence:
Metals are not usually used in their pure state. Instead, they are ________ with other metals or non-metallic elements (like carbon).
Metals are not usually used in their pure state. Instead, they are alloyed/mixed with other metals or non-metallic elements (like carbon).
Chipboard is obtained from wood chips that are mixed with resin and then pressed.
Complete the sentence:
House lights and street lights are connected in_____. That way, if one breaks, the others still work.House lights and street lights are connected in PARALLEL. That way, if one breaks, the others still work.
When electrons move through a conductor or load device, they create friction with the material as they pass through, which produces heat. This effect is known as the Joule effect.
Examples: Toaster / heater ...
Explain the difference between an CLOSED circuit and a SHORT circuit.
A circuit is CLOSED when the energy of the power source reaches the load devices, so the electric current flows.
A SHORT circuit occurs when the electric current is transported by the wires without passing through a load device.
A material is ELASTIC if it recovers its initial shape, like rubber.
A material is plastic if it stays deformed when the force that deformed it has disappeared, like clay and plasticine.
What material is obtained if copper and tin are combined?
Complete the sentence:
Electrical wires are made out of ______ because they are good electrical conductors.Electrical wires are made out of COPPER/STEEL because they are good electrical conductors.
I = V/R
R = V/I
Write the name and the symbol of four load devices.
Depending on the percentage of CARBON in the alloy, ferrous materials can be classified as: iron, steel and cast iron.
Tough materials: Steel, wood, most plastics...
In parallel circuits:
The intensity does not flow equally through all the load devices; instead, it is shared by all the possible paths. // It = I1 + I2 + I3
If one element breaks, the other steel work.
1/Rt = 1/R1 + 1/R2 + 1/R3
Draw a circuit where 4 lamps connected in parallel may be turned on and off from two different points.