Why magnets have two poles
Each particle had a random position and velocity. Gravity caused the dust to contract. Because some portion of their motion was in a direction perpendicular to the direction gravity was pulling them, the particles would have started to spin.
This is analogous to the way your arm rotates when you catch a ball. Since they were moving around randomly, most of the spinning throughout the entire cloud would cancel out, but there would have been a little bit left in one direction just by chance. As the dust ball condensed more and more, the speed of the spinning ball would grow, because of the conservation of angular momentum. The ball would also eventually form a disk.
To understand this, imagine a spinning globe. Notice that the top and bottom points of the globe aren't moving. The particles on the top and bottom of the dust ball don't have enough speed to prevent them from being sucked into the center plane, so the whole thing squashes into a disk. From the intial cloud of dust, we're left with a disk of material spinning around a preferred axis. From this the Sun and planets formed, each continuing to spin along the direction of the disk.
The planets all rotate more-or-less in the same direction the Sun does with the exception of Uranus and Venus which had their rotations changed by other effects. When the inner core moves against the outer core, this makes earth turn into one huge magnet.
Introduce lesson by reviewing what we already know about magnets. Give each pair an experiment sheet to complete.
Explain and model how to do sheet with out actually doing the experiment. Tell students to draw using arrows what happens when they touch each of the sides together. Colloquium and drama: Discuss their discoveries. Have children act this out.
One child could be north and hold his hands in front of him. The other child will be north also and do the same. The two will not join but push each other away. For south- Children will have hands to the sides. As they come together they will not join. Tell children, "Magnets are like friends they do not like sides that are just like them, they want to meet some one different.
Students will be assessed by their participation in the experiment and the colloquium. Students will also complete a drawing of the experiment. Actually, the Earth's north and south magnetic poles reside deep within the earth's center.
This has some interesting information that talks about how the earth has magnetic poles. It clears up misconceptions about this. This lesson challenged the students to think about magnets and allowed them the opportunity to explore and discover on their own the properties of magnet poles. The rule is: wherever there is stored-up energy in an object and the object is not tied down or stuck in place , then the object will be pushed in the direction that causes the stored-up energy to decrease.
The stored-up energy will be reduced and replaced by movement energy. So if two magnets are pointing with unlike-poles together north pole to a south pole , then bringing them closer together decreases the energy stored up in the magnetic field.
They will be pushed in the direction that decreases the amount of stored-up energy. That is, they are forced together this is called attraction. If two magnets are pointing with like-poles together a south pole to a south pole OR north to north , then stored-up energy will decrease if they move apart.
So our rule says the magnets will be pushed in the direction that decreases the amount of stored-up energy. That is, they are forced apart repelled. Earth is also surrounded by a gravitational field which also contains stored up energy. Unlike magnetism, gravity never repels because gravity only points one way. There are no north and south poles for gravity.
Read more: Earth's magnetic heartbeat, a thinner past and new alien worlds. The energy needed to pull the magnets apart comes from you, and you get it from the food you eat. And the plants or animals you eat get their energy from other plants and animals, or from the Sun.