Oxford 6th ggrade. unit 5. Electricity and magnetism.

1. Electricity and magnetism
Unit 5 Natural sciences
My explanation:
introduction to the
unit

2. What do
you know
about
electricity?
• Nothing? Are you sure?
• Probably you know that electricity travels
through wires (cables)
• Probably you also know that it is useful to
make things work (such as the TV, the
mobile phone, the microwave, the Nintendo
or the hair drier)
• And maybe you also know that there is also
electricity in the clouds, when there is a
storm and you see lightning (relámpagos)

3. But, how does electricity work?
• Electricity works because of the movement of some particles from
one place to another, travelling along a wire or any other conductor.
• These particles are called ELECTRONS (and that is the reason for the
name electricity)

4. And now the big question: what is an electron?
• Let´s going to start with the basics:
THE ATOM
• Do you remember what is an
atom?
• Atoms are the smallest particles
that matter is made up of.
• Well, that is not exactly true,
because atoms have smaller
particles inside.
• Let´s have a closer look to an atom

5. THE ATOM

6. PARTS OF AN ATOM
• The nucleus: it is in the middle. It has two
types of particles:
• Protons: they are particles with
electric charge (positive)
• Neutrons: they are particles with no
electric charge
• The electrons shell: it is around the nucleus
and it is very big
• Electrons: they are tiny particles with
electric charge(negative)

7. Summarizing.....
(I am joking)

8. Review of particles (for real they have no color
or marks)
• Protons: they are in the nucleus and they have positive charge
• Neutrons: they are in the nucleus and they have no charge
• Electrons they are in the electrons shell and they have negative charge.

9. Very good, but how can electrons move?
• The outermost electrons can move along a wire because they are
forced or are atracted by a positive charge (remember they are
negatively charged)
Wire (cable)
Electric circuit
Battery (pila)

10. Charged atoms
(ions), static
electricity and
circuits
My explanation: ions,
static electricity and
circuits

11. Some curiosities about atoms
• Atoms of elements can be positive, negative or neutral.....how?
• By counting the electrical charges of the subatomic particles
• Each proton counts 1 positive charge 1+
• Each electron counts 1 negative charge –1
• The neutrons are not counted (as they have no electrical charge)
• The charges positives and negatives are added and the result can be:
• Higher than 0: total charge positive: the atom is positive
• Lower than 0: total charge negative: the atom is negative
• If they have the same number of protons than electrons, they are neutral
and stable (the total charge is 0)

12. ions (iones)
• Atoms with electrical charge (+ or -) are called
ions.
• Positive ions : also called cations (cationes)
• Negative ions: also called anions (aniones)

13. Let´s put this into
images
• Count the number of protons and
electrons of this atom.
• Protons: +6
• Electrons: -6
• Total charge: 0
• This is a neutral atom, it is stable
A neutral atom of Carbon

14. And now... other
example
• Count the number of protons and
electrons of this atom.
• Protons: +3
• Electrons: -2
• Total charge: +1
• This is a positive atom: a cation

15. And now... another
example
• Count the number of protons and
electrons of this atom.
• Protons: +9
• Electrons: -10
• Total charge: -1
• This is a negative atom: an anion

16. Practice and play
• Build atoms:
• https://phet.colorado.edu/sims/html/build-an-
atom/latest/build-an-atom_en.html
• Periodic table interactive:
• https://www.ptable.com/

17. A deduction....
• If we change the number of protons, it
becames a different atom (another
substance... oxygen, boron, fluorine...)
• If you change the number of electrons, it
is the same substance but with an
electrical charge. (it becomes an ion)

18. What can we do to atoms?
• Usually we cannot change one substance into
another. We cannot modify the number of
protons.
• That can happen with radioactivity or nuclear
reactions (only in very big atoms)
• But we can easily change the number of
electrons in many substances
• (adding more or taking them away )

19. Do you want to modify the number of
electrons on your hair?
• Experiment:
• Materials:
• A balloon
• Your hair
• Procedure:
• Rub the balloon on your hair
• Now tell me: what happened to your hair? (if you
have a very short hair, ask for a volunteer)

20. Explanation

21. Yuppiiiiiii!!!!
You have
created static
electricity!!

22. Do you want to try another experiment?
• Materials:
• A plastic pen (boli bic)
• A woolen sweater (your school
one will work)
• Very small pieces of paper
• Procedure:
• Rub the pen on the woolen
sweater
• Place it close to the pieces of
paper
• What happened?

23. Explanation
• The plastic gets electrons from the wooden
sweater
• The plastic is now negatively charge
• The paper has a natural positive charge
• Positive and negative charges attract each other.

24. What happens in a
circuit?
• The electrons are continuosly
forced to move from one atom to
the next along the wire (usually
made up of metal) by a force (the
battery) that attracts them.
• The flow of electrons is called
current (corriente)

27. Magnets
My explanation
about Magnets

28. What is a
magnet? (imán)
• A magnet is an object or a material that produces a magnetic field (campo
magnético)
• The magnetic field is invisible but it has an amazing property:
• Attracts metals (iron, steel, cobalt, nickel...)
• Attracts or repels other magnets
• There are natural magnets (magnetite-magnetita- for example) that are
permanent.
• But magnetic properties can also be produced by other magnets or by electricity.
(electromagnets) (electroimanes), so sometimes, magnetic properties can be
temporary

29. How do magnets work?
• All magnets have north and south poles.
• Opposite poles are attracted to each other
• While the same poles repel each other.

30. Some amazing experiments with magnets (click on the images)

31. What is a magnetic field?(campo magnético)
• It is a region around the
magnet where there are
magnetic properties
• Is it visible? No, it is not.
• How can we make it visible?
• By placing some iron fillings
(limaduras -trocitos
pequeños- de hierro) around
the magnet
https://www.khanacademy.org/science/physics/discoveries/magne
tic-fields/v/discovery-of-magnetic-fields

32. Lines around the magnet show the magnetic field, as
in this model.
• Magnetic force travels from
the north pole to the south
pole of the magnet
• North >>>> South
N S

33. When we have two magnets their magnetic
fields interact in the following way:
N N
When they repel each other
N S
When they attract each other

34. Challenges
• Magnetize objects:
• Take a magnet (one from the fridge will work)
• Attract a paper clip (or a staple-grapa-)
• Use the magnetized paper clip to attract another paper clip
• Trace the invisible magnetic field:
• Use a compass-brújula- (one app from the mobile phone can
work as well if you don´t have one)
• Place the compass on a table
• Little by little bring a magnet closer to the compass.
• Measure the length of the magnetic field: from what
distance to the magnet does the compass move? (the stronger
the magnet, the bigger the magnetic field)

35. More challenges
• Effect of electric current on a compass:
• Go next to a wire of a household appliance-electrodoméstico-
(lamp, hair drier, nespresso, toaster, mobile phone....with your
compass)
• Turn on the household appliance and check the compass. Did
it move?
• Why? >>>>> Moving electrons create magnetic fields, so any
wire with electric current has a magnetic field.
• Glass with water and paper clips inside.
• Try to take the paper clips out of the glass without touching
the water (the magnet cannot touch the water either)
• Answer the question: Can magnetic fields travel through
objects and different materials?

36. The last one:
make a
compass
(brújula) (click
on the image)

37. Earth´s magnetic
field
(campo
magnético
terrestre)
My explanation:
Magnetosphere

38. Vocabulary
Magnetic field: campo magnético
Magnetosphere: magnetosfera
Compass: brújula
Magnet: imán
Magnetic poles: polos magnéticos
Geographic poles: polos geográficos
Steel: acero
Solar radiation: radiación solar
Liquid iron: hierro fundido

39. What is there
inside our
planet?
A melted metal moving very fast can produce a
magnetic field
The core is liquid iron spining at a very high speed and
that produces a magnetic effect: it is like the effect of
a magnet.
There are three main layers:
The crust The mantle The core

40. Types of solar
radiations
• Sun is formed by different types of light and rays.
• Visible light
• UV: ultra violet
• IR : infra red
• Gamma rays
• Microwaves
• Solar storms

41. Why is our magnetosphere so important?
• It is a shield (escudo)
for the dangerous solar
rays.
• Some of them are really
really dangerous for
life.

42. Useful and
amazing
properties of
the
magnetosphere
• Auroras (boreal-north- and
austral-south-)
• Orientation with a compass

43. Auroras borealis and australis

44. Other curiosities
• The geographic poles are
NORTH UP and SOUTH
DOWN
• The magnetic poles are
the OPPOSITE
• They don´t exactly match
(the magnetic south is not
in the same point as the
geographic north)
• The compass
needle points to the
Magnetic South Pole (that
is very close to the
Geographic North pole)
Magnetic South Pole
Geographic North
Pole
Magnetic
South
Pole