8E Electromagnets Flashcards
What is the area of magnetism around a magnet called?
A magnetic field
What is the strongest type of magnet?
Neodymium
What is the most common material to make a magnet from?
Iron
What is the term for being able to hold an alignment of atoms?
Hysteresis
What is a magnetic moment?
When atoms have a tiny magnetic field
How can you weaken magnetism?
Dropping, heating or hammering them
What is a coil of wire called?
A solenoid
How is an electromagnet different to other magnets?
Not permanent. It can be turned on and off.
What is a magnetic field?
Area where an object has a magnetic influence
Which 2 Scientists made discoveries about magnetism?
Faraday and Maxwell
What can affect magnetic strength?
The material an object is made of
Where do the magnetic field lines begin and end?
At the poles
Why do we have North and South Poles on the Earth?
It is the place where the planet’s magnetic field lines come together
What is a moving charge called?
Current
What happens to objects that attract?
Move towards each other
What happens to objects that repel?
Move away from each other
How can we detect earth’s magnetic field?
Using a magnetic compass
What does dipole mean?
It has two poles (north and south)
What is a magnetic reversal?
When the poles switch
How do we know about reversals?
In the geological record at mid ocean ridges
What equipment is used to detect reversals?
A magnetometer
Where is the youngest oceanic crust found?
Closest to the Mid ocean ridge
What happens in a magnetic anomaly?
The poles weaken in strength and the direction changes
What happens to rocks because of the earth’s magnetic field?
The magnetic minerals orientate depending on the direction of the magnetic field
What is electromagnetism?
How a magnetic field is created by the flow of a current
What happens when a current passes through a wire?
A magnetic field surrounds the wire
If the current flows up which direction is the magnetic field?
Anticlockwise
If the current flows down which direction is the magnetic field?
Clockwise
What does a motor do?
Converts electrical energy into movement
What happens when a current moves through a magnetic field?
A force occurs
What is induction?
Induction is when movement is used to create electricity
What is a generator?
When mechanical energy is converted into electrical energy
What happens when you turn an electromagnet on?
A magnetic field is created
Why would a permanent magnet be a problem in a scrap yard?
Would not be able to release the objects
What is an advantage of using an electromagnet?
Can be turned on and off
What is meant by segregating?
To separate materials
Why can only ferromagnetic materials be removed using a magnet?
Because only they are attracted to a magnet
Why does the clapper become magnetic?
Because the circuit become complete
What must happen for the bell to continuously ring?
The circuit breaks and reconnects
Why might some cars not be picked up?
Not all cars are ferromagnetic. Some are fibreglass
What is the independent variable in the experiment?
Number of turns/coils in the wire
Identify the equipment required in the experiment.
Wire, iron nail, wire and crocodile clips, paper clips, Power supply,
What is the dependent variable in the experiment?
Number of paper clips picked up
Name 2 control variables in the experiment.
Voltage and type of core
Why should you disconnect the circuit when you are not using it?
Batteries will drain, wire might get hot
How can you turn the electromagnet off and on?
Using a switch
How can you tell if the electromagnet is working?
If it picks up magnetic materials
Why should you calculate the mean number of paper clips?
To check for anomalies
What are the 3 main stages in scientific investigations?
Planning, collecting results, analysing
What is a prediction?
Using our understanding to guess what might happen
What is a variable?
A factor that can be changed or measured in an investigation
Which variable is measured?
The dependent variable
What is the name of a variable that is kept the same?
Control variable
Define the term independent variable.
The variable that you change
What information is included in the method?
Apparatus, Measurements, readings that we will take, safety issues/ risk assessment
Why should you disconnect the circuit when you are not using it?
Batteries will drain, wire might get hot
How can you turn the electromagnet off and on?
Using a switch
How can you tell if the electromagnet is working?
If it picks up magnetic materials
Why do we draw a graph of experimental results?
To look for a pattern
Why is drawing a line of best fit important?
Check for anomalies
Where do we plot the independent variable on a graph?
X axis
Where do we plot the dependent variable on a graph?
Y axis
How do you draw a line of best fit?
Usually with a ruler or a curve
