Have you ever wondered how a compass works?

Compasses

How many of you have used a compass before?

Can you explain how it works?

Magnetism

Do all metals have magnetic properties?

What three metals have magnetic properties?

Magnetic Metals

IronNicke

lCobal

t

Magnetism !

Magnets produce a force around them that pushes and pulls on other matter that is also magnetic. When things made of magnetic metals or other magnets come close to this region of force, they feel a pull or a push from the magnet. Scientists call these invisible areas of pushes and pulls FIELDS.

Let’s Explore!!!

Explore Magnetic Fields

Now lets explore the fields of magnetic forces around magnets!

What you will need: bar magnet, iron filings, piece of white paper , two pencils, plastic tub/ box top

Steps: Lay the bar magnet in the bottom of the box top. Lay two pencils parallel to it. Put the piece of white paper on top. Carefully sprinkle the iron filings on top of the paper, SLOWLY AND LIGHTLY, looking for a pattern to develop.

Draw the pattern you see formed by the filings.

Magnetic Fields

Explore Using a Compass

What you will need: bar magnet and a compass

How will a compass act as you move it around a bar magnet?

Place the bar magnet down on the table and begin moving the compass around the boundary of the magnet observing how the needle moves.

Write down your observations. You may also draw a diagram to help explain what you are observing.

Can you see the magnetic fields with the compasses?

http://indianapublicmedia.org/amomentofscience/make-your-own-compass/

The Earth is a Giant MagnetA compass works the way it does because Earth has a magnetic field that looks a lot like the one in a magnet. The Earth's field is completely invisible, but it attracts a compass needle on the Earth's surface. The field around Earth reaches thousands of miles out into space. http://bluebird.physics.ualberta.ca/carismaweb/content/

view/69/1/

HTTP://WWW.YOUTUBE.COM/WATCH?V=IE_6T84QUMQ

Is Earth the only planet that has

magnetism?

Magnetosphere

Interestingly enough, if you were to take a rocket ship into space and study the Earth's invisible magnetic field, it wouldn't really look like a bar magnet at all. Earth's magnetic field gets stretched out into a comet-like shape with a tail of magnetism that stretches millions of miles behind the earth, opposite from the sun. The sun has a wind of gas that pushes the earths magnetic field from the left to the right. This area around the Earth where the magnetism dominates is called the magnetosphere.

Can you see the magnetic field around the Earth?

http://www.universetoday.com/61456/magnetosphere/

Magnetic Field of Earth Protects Us!

Earth’s magnetic field shields us from the solar wind which is space radiation, highly charged particles that blast out from the sun like a wind.

The Earth’s magnetosphere channels the solar wind around the planet so that it doesn’t impact us. If we did not have a magnetic field, the solar wind would strip away our atmosphere.

Aurora Borealis “The Northern Lights”

Once the rays of the solar wind have passed by the earth, some of them move back along the lines of magnetic force to the north and south poles. When the rays strike the upper regions of the atmosphere, the Aurora Borealis (Northern Lights) or Aurora Australis (Southern Lights) are formed.

http://goodnature.nathab.com/northern-lights-natures-winter-magic/

You can even see magnetic fields in the solar winds around the sun!

http://trace.lmsal.com/POD/

The Core Causes Earth’s Magnetism

The core of the Earth is an electromagnet. The solid iron and nickel inner core of the Earth is surrounded by the outer core, a mixture of molten iron and nickel.

The inner core spins inside the outer core and creates currents of electricity. The magnetic field of Earth is caused by these currents of electricity that flow in the molten core.

These currents are hundreds of miles wide and flow at thousands of miles per hour as the earth rotates. The powerful magnetic field passes out through the core of the earth, passes through the crust and enters space. http://image.gsfc.nasa.gov/poetry/tour/AAmag.html

Using a CompassThe magnetic field of the Earth is

weakened a lot by the time it reaches the surface of the Earth, but is strong enough to move the needle of a compass.

All magnets have two poles, a North Pole and a South Pole. Opposite poles of magnets are attracted to each other: north is attracted to south.

The north pole of the Earth is actually its magnetic south pole, which makes the south pole the magnetic __________ pole.

How do you use a compass?

Video: Compass 101:How to Use a Base Plate Compass

http://www.youtube.com/watch?v=7MQUIYsmQhc

Resources

http://image.gsfc.nasa.gov/poetry/tour/AAmag.htmlhttp://www.universetoday.com/61456/

magnetosphere/http://trace.lmsal.com/POD/http://bluebird.physics.ualberta.ca/carismaweb/

content/view/69/1/http://indianapublicmedia.org/amomentofscience/

make-your-own-compass/ http://goodnature.nathab.com/northern-lights-natures-winter-

magic/ http://www.explainthatstuff.com/magnetism.html