2019-06-20 1 Electricity WORD SPLASH
2019-06-20
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Electricity
WORD SPLASH
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Huh?? Why did the balloon stick to the wall?
The balloon started out neutral
When we rubbed it against out hair, negative charges
from our hair moved onto the balloon resulting in the
balloon being negatively charged.
Transferring Charges
Hair and wool are materials that
readily give up negative charges
When the negatively charged balloon
is brought near the neutrally charged
wall, the wall become positively
charged
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Opposites Attract The common saying “opposites attract” is fundamental
to why the balloon then sticks to the wall.
Since the balloon is now negatively charged, it is
searching out the positive charges located in the wall
It will also search for the left over positive charges from
our hair (floating hair!)
It works the same way for neutral and positively
charged objects
Static Electricity This phenomenon is called static electricity
When have you experienced static electricity before?
Opposites attract
Likes repel
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Huh? What did you notice from our hand holding
demonstration?
What about with the marbles?
What lesson can we take from this?
Current Electricity Using the materials provided (2 wires, a battery and a
light bulb), try to light the bulb
Share with the class what solutions you discovered
How does this relate to our hand holding demonstration?
Show/explain how you made the materials work in your science journals
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Current Electricity Electricity is the flow of electrons (negative charges)
through a conductor.
Current electricity is produced when negative charges
move along a path (circuit)
Both static and current electricity
involve the movement of negative
charges
Electricity can be Dangerous! Both static and current electricity can be dangerous –
let’s review some basic safety measures
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Static Electricity Safety Do not play outside during a thunderstorm
Lightning often takes the easiest path from the clouds to
the ground.
It is easier for static electricity to go through a person than
to take the long way around and go through the air
It is even easier to travel through a gold club or baseball
bat
Static Electricity Safety Do not take cover under a tall tree during a
thunderstorm
Lightning can hit the top of a tree, travel down the trunk,
and then channel into a person standing under it
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Static Electricity Safety Do not swim during a thunderstorm
Lightning can hit the water and the electricity can channel
into a person in the water
Current Electricity Safety Do not use appliances/devices that have cords with
exposed wires
A short circuit can happen when the outer covering of
wires is worn or when wires touch one another
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Current Electricity Safety Do not overload an electric socket
Heat is produced as electricity passes through wires
If too many wires are plugged into one outlet, the heat
produced can cause a fire
Current Electricity Safety Do not play near power lines
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Current Electricity Safety Never put anything but a plug into a socket
Other objects can conduct electricity and cause a shock
Current Electricity Safety Do not unplug an appliance by pulling the cord. Always
use the plug.
The cord can become damaged and can cause an
electrical shock
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Current Electricity Safety Do not use electrical appliances when you are in or
near water.
Water is a conductor of electricity and if in contact with an
electrical appliance can conduct electricity
Louie
Safety Posters
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Human Uses
In your Science Journals, conduct a survey of human
uses of electricity – where do we use it, how do we use
it and why. How did we do these activities prior to
electricity?
Insulator or Conductor What materials could we test to investigate whether or
not the are capable of conducting electricity?
Try to think of a range of materials – like what we can
recycle, or even what we can’t recycle!
Predict which ones can and which ones can’t
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Insulator or Conductor Using the following materials, investigate materials that
conduct electricity.
Based on your findings, develop a definition for the terms insulator and conductor in your Science Journals and identify what materials would work best to insulate a wire and which would best conduct electricity in a switch.
Switches Electrical switches serve the function of operating
electrical circuits
Think of a circuit like running around a room while always
having to touch the side
When the doors are all closed, you can keep running and
running
When the door is opened, you get stopped because your
hand can’t “jump” the system
By closing an electrical switch, the negative charges
are able to flow through the circuit. When the switch is
opened, the charges can no longer flow.
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Circuits Construct a circuit using one battery and three light
bulbs similar to the system we created before.
Draw and label your circuit in your Science Journal
Predict what will happen if you unscrew one of the light
bulbs. Explain your thinking then test your prediction
Circuits Try to create a circuit that will allow the remaining light
bulbs to stay lit even when one light bulb is removed.
Explain in your Science Journal how you re-designed
the circuit and how it works.
Include a labeled diagram
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Circuits The two types of circuits that were created are called
parallel and series.
Which title belongs to which diagram? Why?
Provide examples of when parallel and series circuits
are used and what would happen if we switched them
for the opposite circuit
These circuits are like climbing a tree using a ladder or
a rope
Brightness Experiment with the materials provided. In your
Science Journals, indicate what happens to the
brightness of the bulbs when you change factors.
Record what you change and what impact it has on the
brightness in a chart
Remember to alter only one
factor at a time to ensure it is a fair
test
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Design project Construct a prototype to solve the following design
challenge:
A construction company has hired you to develop a
security system for new houses. They want a system
that uses an electrical circuit either to set off an alarm,
or to turn on lights if a house is entered illegally. Before
you install the system, you are required to build a
prototype to demonstrate how the system works.
Design project
As a class, develop criteria that address the scientific
components of the task (e.g., complete circuit, switch)
and a variety of other criteria (e.g., appearance,
durability).
Each group will present their prototype to the class,
identifying problems they had in designing and building
it, and explaining how these problems were overcome.
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Electromagnet1. Hold the nail. Wrap the middle section of the wire
tightly around the nail, starting from just below the
head down to just above the point of the nail.
2. Tape one end of the wire to the negative end of the
battery and the other to the positive end.
3. Try to pick up the objects with the nail. Record your
observations.
4. Disconnect the wire from the battery and try to pick up
objects. Record your observations.
5. In your Science Journal, explain your results. Why do
you think this happened?
Electromagnet Each negative charge is surrounded by a force called
an electric field.
When the charge moves, it creates a second field – a
magnetic field
When negative charges are made to flow in a current
through a conductor, such as a piece of metal or a coil
of wire, the conductor becomes a temporary magnet –
an electromagnet
Marshall Brain can explain this to us nicely
Fee free to try his additional experiments at home with
permission from your parents
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Constructing
a Simple
Motor
Constructing a Simple
Generator How to make a very simple generator
If you try this at home, always ask your parents first!
Simple generators can be very useful in our daily lives
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Generators Generators require a source of energy to create a
turbine motion – an electromagnetic source of
electricity
Some generators use water, steam or even wind
Transformation of Energy Energy cannot be created
or destroyed.
It can only be transformed into something new.
If we eat food, we get energy. We use that energy to move, work, play, grow, build…
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Types of Energy Discuss as a class how electrical energy is transformed
into different forms of energy.
Make a list of the various ways it is transformed.
Complete the Journal sentences.
Batteries A battery changes chemical energy into electrical
energy
A dry cell battery is made up of a zinc case with a carbon
rod in the centre. The space between is filled with a
chemical paste. Turning on the switch connects the zinc
and the carbon. A chemical reaction takes place, creating
a circuit through which negative charges can move
Lemons can make simple batteries
A car battery is a wet cell battery made up of layers of
lead. The cas contains water and acid instead of chemical
paste. The lead and the acid cause a chemical reaction
that produces an electrical current.
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Energy Sources:
Hydroelectric Positive Points
Water is a renewable resource
Water is readily available (at least in Canada)
It is cheap to produce
It is relatively pollution free
Negative Points
Land has been flooded to create reservoirs for
hydroelectric plants. As a result, habitats have been
destroyed
Long systems of transmission lines are needed to carry
electricity to where it is needed, and these are expensive
Energy Sources: Coal
Positive Points
Coal is cheap
A large quantity is still available
Other products can be created from coal
Negative Points
Coal causes air and water pollution
Mining has an impact on the environment and is
dangerous for miners
Coal will eventually run out (it is non-renewable)
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Energy Source: Wind
Positive Points
Wind is a renewable energy resource
There are no fuel costs
No harmful polluting gases are produced
Negative Points
Noisy
May spoil the view for people living nearby
A significant amount of land is required
Energy Source: Geothermal
Positive Points
Renewable because once water or steam is used, it can
be pumped back into the ground
It is clean energy – it does not produce greenhouse
gases harmful to the atmosphere
Negative Points
There are potential emissions – Greenhouse gases below
the Earth’s surface could migrate to the surface
Construction of a plant can affect the stability of land
Electricity is still needed to operate heat pumps
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Energy Source: Solar Positive Points
Pollution free – no Greenhouse gas emissions after
installation
Reduces dependence on oil and fossil fuels
Produces power every day – even cloudy days produce
some
Negative Points
Relatively high cost, especially with storage (need
batteries)
Requires a large amount of open space
Fragile materials with relatively low efficiency
Energy Source: Nuclear
Fission Positive Points
Reduces consumption of fossil fuels (coal and oil)
Less expensive
Reliable
Very low Greenhouse gases
Negative Points
Non-renewable
Accidents can release large amounts of radioactive
material into the environment
The waste remains radioactive and hazardous for
thousands of years
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Energy Source: Oil
Positive Points
Small amounts of oil can produce large amounts of
energy
Due to our vast experience with oil technologies, we can
produce ways to utilize oil efficiently
It is reliable
It creates many jobs in Canada
Negative Points
Non-renewable source of energy
Burning oil produces carbon dioxide gas
A lot of oil needs to be imported and is becoming
increasingly expensive