This document provides information about static electricity and how static charges are generated. It explains that static electricity occurs when electrons are transferred between two materials that are rubbed together, leaving one material with an excess of electrons and a negative charge, and the other with a deficit of electrons and a positive charge. The document also discusses how static charges can be identified by whether they are attracted or repelled by a negatively charged rod, and how materials can become charged through friction, induction, or conduction.

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Presentation Time!
Experiment 4
Groups 4 and 5

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What is static electricity?
What do these things have
in common?
 Crackles when combing
hair.
 Getting a shock when
rubbing
your feet on a carpet.
 Lightning.
They are all caused by
static electricity.

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Where does static charge come from?
All materials are made of atoms, which contain electric
charges.
An atom has equal amounts of negative and positive charges
which cancel each other out. This means an atom has no
overall charge.
Electrons do not always stay attached to atoms and can
sometimes be removed by rubbing.
electron
(negative
charge)
proton
(positive
charge)

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Where does static charge come from?
Static charge can build up when
two materials are rubbed together,
such as a plastic comb moving
through hair.
When this happens electrons are
transferred from one material to
the other:
 One material ends up with more electrons, so it now
has an overall negative charge.
 One material ends up with fewer electrons, so it now
has an overall positive charge.

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An insulating material can be charged by friction.
For example, if an insulator is rubbed with a cloth, it can
become charged in one of two ways:
What is the name of the force between two materials that
are rubbed together?
friction
Creating static charge
A. Electrons move from
the cloth to the insulator.
B. Electrons move from
the insulator to the cloth.

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If an insulator made of polythene is rubbed with a cloth,
electrons move from the cloth to the insulator.
The cloth is positively charged.
The insulator is negatively charged.
What charge does the cloth now have?
What charge does the polythene insulator now have?
Charging by friction

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If an insulator made of acetate is rubbed with a cloth,
electrons move from the insulator to the cloth.
Charging by friction
The cloth is negatively charged.
The insulator is positively charged.
What charge does the cloth now have?
What charge does the polythene insulator now have?

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Static charge – true or false?

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Pairs of charges – attract or repel?

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Identifying an unknown charge
 If the unknown charge is brought near to a negatively
charged rod and it is attracted to this rod, then the
unknown charge must be ________.
 If the unknown charge is brought near to a negatively
charged rod and it is repelled by this rod, then the
unknown charge must be ________.
positive
negative
?
If a rod has an unknown charge, how can the unknown
charge be identified using a negatively charged rod?

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+ - + - + -
+ - + - + -
+ - + - + -
Charging by induction

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Charging by conduction

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To summarize…
Materials can be charged in three
ways:
1.Friction – by rubbing them together
2.Induction – charging where an object
can be charged without actual
contact to any other charged object
3.Conduction – involves the contact of
a charged object to a neutral object

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VIDEO
Electric Charge
Crash Course

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Grounding
The process of removing the charge on an object is called
discharging. When discharging is done by means of providing a
path between the charged object and a ground, the process
may be referred to as grounding.

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Go back to your table
earlier and try to
correct your answers.

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1, 2, 3
GO!

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1. Elsa is sitting very still on a chair.
But Jose claims that Elsa is actually
moving. Jose is correct if the point
of reference is the _____.
1 – chair
2 – Earth
3 - Sun

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2. A toy when whirled has a uniform
speed and moved in a circular path.
Which of the following is/are true?
I - The toy has a uniform velocity
II – The toy is accelerating
1 – I
2 – II
3 – I and II

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3. Waves in a lake are 5.00 m in
length and pass an anchored boat at
1.25 s apart. The speed of the waves
is:
1 – 0.25 m/s
2 – 4.00 m/s
3 – 6.25 m/s

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4. Wave X makes five full waves in
two second. What is the frequency
of wave X?
1 – 10 Hz
2 – 5 Hz
3 – 2.5 Hz

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5. Which of the following is not
capable of transmitting sound?
1 – air
2 – ice
3 - vacuum

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6. Which of the following would
most likely transmit sound best?
1 – steel in a cabinet
2 – water in the ocean
3 – air in your classroom

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7. ROYGBIV is the basic component
of white light. Among the colors
below, which color of light carries
the highest energy?
1 – BLUE
2 – ORANGE
3 – RED

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8. Which of the following is a proof
that light travels in a straight line?
1 – formation of shadows
2 – formation of clouds
3 – formation of colors

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9. Your classmate is electrocuted
accidentally. Where would you NOT
grab her so you could save her
without you being electrocuted too?
1 – by the hair
2 – by her metal bangles
3 – by her rubber shoes

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10. What is the middle name of your
trainer today?
1 – Aguila
2 – Aguilar
3 - Eusebio

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–RenzCeliz,2018
“A peaceful classroom
never made a great
educator."