Explorabox Teacher's Guide.
Everything you need to know to plan hands-on activities, and guide the learning of science!
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Everything you need to know to plan hands-on activities, and guide the learning of science!
Get Materials!
We currently follow the California Department of Education Science Content Standards. We will also follow the Next Generation Science Standards (NGSS).
Children should be instructed to open their boxes and take out the ring and bar magnets. Let them play with them for a little while. Guide and encourage them to place the magnets on a table.
Can they get another magnet to move without touching it? Can you create interesting configurations? Finding a friend, take two bar magnets and observe what happens when N+N come near. What about N+S?
Have students work preferably in groups. Challenge them to create an antigravity machine that can levitate a paper clip. All materials are provided in the kits, apart from a small cup to provide some height for the pencil to rest on. Any other object that can prop up the pencil will also work.
Ask the students to try attracting different materials. What do they notice? They should conclude that only certain types of metals stick to their magnets (including the paper clip). You will explain in the next activity why that is, and what is going on inside the magnet.
Students will be mesmerized with this activity! In each explorabox is a small petri dish filled with fine pieces of iron that look like light powder. When a magnet is placed under the petri dish, the field lines cause the filings to become magnetized.
When this happens, the iron pieces align themselves with the magnetic field. You can thus get an idea of what the magnetic field lines look like for a particular magnet. If you're wondering what a magnetic field exactly is, think of it like a description of the magnet's region of influence. If you could measure with a tiny instrument the amount of force the magnet exerts in the space around it (and the direction), you'd be able to construct the field. Explain this to your students, and as a fun activity, have them sketch out the field lines for the bar and ring magnets.
Here is where students may be asking what is exactly going on. What makes certain materials stick while others don't? They should notice that certain metals (like iron in paperclips, etc.) will stick to the magnets, while other materials like plastics don't. The reason for this is due to magnetic domains that occur in the material's microstructure. A domain is a region of material where the atoms's magnetic poles (north and south poles) are lined up with each other. You can actually see this under a microscope:
When you pass an external magnetic field through this material, the domains line up. This causes the magnetic forces to amplify, so that an external force (that you can feel) is created. This is why paperclips stick to magnets!
A residual magnetization can be created by rubbing one pole of a magnet across a piece of metal. Students can experience this by rubbing the south pole of the bar magnet 10-15 times along the metal pin. Make sure that contact is made in only one direction (lift away from the pin when moving in the other direction). The magnetization is pretty weak, so you have to be careful to see it. If there is a stronger magnet in the classroom, you can try using that to see a greater effect.
This fascinating activity allows students to make their own compass and see that the entire planet acts like a large magnet. Make sure the students have magnetized their pin (without taking it out of the plastic bag). Fill a shallow dish (or foam plate) with water and float the pin (in its plastic) on the water. Students should notice that the pin will always point in one direction, even if you try to turn it. This direction is "magnetic north" and is the direction the earth's field lines go.
The next thing students should do is take the bar magnet and move it near the dish. The pin will move! Try to encourage the students to discover and explore on their own. What happens with the ring magnets? How far away can they be to influence the pin? Explain that compasses are used by navigators so that they always can find their direction.
The basics of this activity will prepare students for the final challenge of the floating pencil (following activity). Students should be able to place their ring magnets freely around the pencil. If the ring magnets don't slide freely, have them shave the pencil down with some scissors (you can help them). Students should get one or several ring magnets to float on the pencil. Don't tell them how to do it, let them figure it out and learn from each other.
A second challenge is to see who can shoot a ring magnet from their pencil. See what kind of configurations people can come up with. Who can shoot the ring magnet the farthest?
This is a challenging activity that takes a lot of patience. Slots should be punched through the foam piece using the sharpened pencil. Just poke holes along the black mark (horizontally). Try to make the slot deep, and it is preferable to make the hole all the way through the foam piece. To set up the experiment, push two magnets onto the pencil. Wrap some tape around the pencil to make sure that the magnets don't slide around and that there is friction to keep them in place. The position of the magnets should roughly coincide with the markers on the foam piece.
Next, place the quarter and magnets into the foam piece. The magnets nearest the quarter should attract the magnet on the pencil. The rear magnets (furthest from the quarter) should repel the associated magnet on the pencil. Balancing the pencil takes practice and adjustment.
Tip: Adjust the position of the magnets on the pencil only. The magnet nearest the quarter should be slightly more towards the pencil's eraser instead of directly over the foam magnets. This allows the attraction to pull the pencil into the quarter, giving it stability. The rear magnet (closest to the eraser) should sit almost directly over the foam magnets, lifting the pencil up. Good luck!
Magnetism
1. Know that magnets have two poles, like poles repel while unlike attract.
2. Know that metals can be magnetized due to alignment of magnetic domains.
Field Lines
1. Know what magnetic field lines are and how they can be traced using iron filings.
2. Know how to build a simple compass and use it to detect magnetic ef fects, including Earth’s magnetic field.
Magnetic Levitation
1. Know that magnets exert a force and that this force can be used to counter gravity.
2. Know that levitation can reduce fiction and allows high speed maglev trains to function.
Collaboration
1. Work together in groups to achieve a difficult scientific/engineering goal.
2. Share resources (box materials) and information to teach each other.