My favorite is the superconductivity demo, but you will need a superconductivity kit and liquid nitrogen (which only a well trained person should handle. IF these are available, there is a lot of fun stuff to discuss! If not, then I'd have to think a little more on other possible demos/hands-on stuff.
Oh, a very simple one that is kind of neat is taking two long and flat/thin magnets- the kind you might get as an advertisement that goes on the fridge- and slide them on each other. At a certain orientation, they will flap against each other- if the magnets are long enough, so use long ones (>1 inch) if you can.
Another idea is to talk about MRI- if you understand the fundamental concepts of superconducting magnets.
The underlying concepts here can be taught to 2nd graders. Best of luck!
I don't think we have easy access to a superconductivity kit and liquid nitrogen. However, your other suggestions are doable. Have you done this with a group of second graders or other elementary school students? If so, would you describe your experience...how they reacted, etc.? Thanks.
While I haven't done this myself with 2nd grade students, I have done this demo with 5th grade students, but I imagine the result will be similar (if not the same). Kids like the fact that they can take simple, every day objects like the paper sheet like magnets and have fun with them. They can even demonstrate this phenomenon to their friends and family just about anywhere such magnets are available. This makes this demo priceless for the students. So, the kids love this demo!
The MRI example is not really a demo, but an explanation of how superconducting magnets work. I happen to work with NMR (nuclear magnetic resonance) spectrometers and happen to know how MRI (magnetic resonance imaging) instruments work. It's the same basic principle. I usually ask my (adult/college) students if any have ever had an MRI image acquired of their body (part) and go from there. Unless you have a good understanding of this process, you may want to stick with the sheet magnets for now.
I just thought of another you can probably do simply: get some iron filings a good magnet (horseshoe or bar or any shape for that matter) and demonstrate magnetic field lines and poles. Place the iron filings on a thin surface you don't mind getting dirty (or can clean easily) and place the magnet below that surface. You can see the alignment of the iron filings with the poles of the magnet. Using an appropriately shaped magnet, you can use it as a model of the earth's magnetic field! There are even inexpensive toys available in discount stores that could work. Again, another simple device that can elegantly explain another concept.
I'm sure there are more appropriate age magnet demos out there, but I have to run off to a meeting!
Best of luck!
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Put iron filings in a thin clear package (restaurant take-out condiments) or a zip-lock bag.
Put an electromagnet on a "crane" or a cord so you can pick up and move some iron objects, mixed with other metals or plastic.
Audio speakers have interaction between permanant magnet and a small electromagnet coil. Glue a ligntweight indicator to the center of the speaker, and use low direct current to move the indicator. Vary the current, and reverse the current to see the effects.
Get or make a reed switch to turn on an LED, and show how the orientation and position of the magnet affects the switch. Put pieces of iron on the magnet or near the switch to reshape the magnetic field. Put the magnet on a pendelum with two strings to keep it from spinning, and swing it just above the reed switch ti see it flash the LED.
Dollar Tree has an entrance alarm based on a reed switch on the frame and a magnet on the door. Have a solderer rewire the batteries (included) through the reed switch, a resistor and a LED.
Put the magnet in a thin small bag, and drag it through some beach or river sand to collect "black" sand. Reverse the bag to remove and collect the black sand.
Weight a cork with a stone and hot melt glue so it floats upright. Drag a steel rod (big needle ) and fasten it to the cork to make a compass. Use a piece of iron or another magnet to confuse the compass.
Use a compass to trace on paper the field of another magnet by drawing dots at the ends of the needle and connecting the dots.
Keyswitch an audio speaker with low direct current to make a telegraph.
Paperclips are good targets for magnets. How many layers of paper will keep the advertisement magnet from picking up the paper clip?
I found these two activities interesting:
Dancing paperclips requires a jar or glass full of water, three paperclips and a magnet. The paperclips are put into the jar of water. Move the magnet on the outside of the jar or glass and the paperclips start moving. Move it as preferred to make the paperclips look like they are dancing. After a demonstration, have the children make the paperclips dance as well.
Magnet kite is an activity that requires paper, a paperclip, string, tape, scissors and a strong magnet. The paper is cut into a diamond shape (like a kite). Cut the paper so that it is around 3 inches long. Attach a paper clip to one of the corners. A string is taped to the paper and then taped to the desk or table. Move the magnet so that it picks up the paperclip. Pull it back until the string is tight and then pull the paperclip away from the magnet. Move the magnet slightly out of range and observe the "kite." It should continue to float in the air. Children learn about magnetic fields with the activity.
Always fascinating: get hold of a strong neodymium magnet (available online from many sources), and drop it down the length of a copper or aluminum tube.
The magnet falls quite slowly, which is weird enough behavior to get anyone's attention:
Kids will play with this for hours.
The full explanation is hard to deliver to youngsters, but you can show a transient magnetic field on the outside of the tube as the magnet falls past, using a simple compass. That's the induced field that's fighting against gravity.
Thanks, James for the link to a very interesting and well-done video.
1. These very strong magnets can pinch pretty badly when attracted to other magnets or magnetic materials.
2. Colliding magnets can shatter.
3. Although generally plated with safer materials, the elements in rare earth magnets may be toxic.
Agreed, you definitely don't want more than one such magnet in the classroom.
I've also discovered, the hard way, that these things can wipe out magnetic strips on credit and ATM cards, bus and subway passes, and the like. They pose a risk to watches, and perhaps to smartphones as well. Carry it in a good-sized box, NOT in your pocket or purse!
Kids can experiment with tubes of different materials (cardboard, plastic, rubber, wood, etc.). Only materials that conduct electricity will slow the fall of the magnet. A few turns of copper wire around a cardboard tube will light up an LED, when the magnet is dropped through, showing that electricity is generated.
I worked for three years in the physics lecture demonstrations lab at U. of Texas, and I'm assuming that 2nd graders magnet and matter lessons only cover: what gets attracted by a magnet, and that magnets have a north and south pole. Meissner effect is cumbersome to get clearance for at an elementary school. Iron filings around a solenoid on an overhead may be a bit too much work, but it also may be irrelevant to their interests.
My suggestion(s): sealed container of evenly distributed, suspended iron filings and a bar magnet similar to a classier version of Wooly Willie, and/or Eddy Currents: either with pendula or the copper tube race, as mentioned in other posts. Here's a Directory of what we had to work with. http://www.ph.utexas.edu/~phy-demo/demo_index.html#index
I strongly disagree with using rare-earth/neodynium magnets unless they are unable to pass through a toilet paper roll. The risk with those magnets, and the reason they have been recently recalled, is that a kid in second grade may swallow a tiny one, which could be catastrophic if the swallowed magnet finds something that attracts it, whether inside or outside the body.
The Chicago Section of the ACS has a number of activities on its website that would be appropriate. For over two decades Dr. Kathleen Carrado-Gregar at Argonne has supplied us with "ChemShorts for Kids" in our newsletter, The Chemical Bulletin, which is currently celebrating its 100th year. If you navigate to Chicago ACS, and use our search tool to look for "magnets", you'll find a number of articles. The full archive of ChemShorts, dating back to 1992, is available here: Chicago Section American Chemical Society - Articles
The top hit is an activity called "Refrigerator Magnet Microscopy": http://chicagoacs.org/articles.php?id=218
Here are the lead paragraphs from that activity; the rest of the article describes the materials and protocol you need to make it an activity:
Kids, how are the north and south poles of a refrigerator magnet arranged? How are chemists able to “see” the atoms that they work with? In this activity you will discover how to answer these questions and also gain an understanding of a cutting-edge imaging technology.
A refrigerator magnet has many north and south poles, not just two as in a bar magnet. The magnetic poles are nearly always arranged in stripes. A thin probe strip cut along one side of the magnet will be deflected up and down when pulled across the back of the magnet perpendicular to the stripes. In this activity the magnetic force between the probe strip and the magnet depends on the distance between the two surfaces and the relative size and alignment of their magnetic fields. By scanning the surface with the probe, an entire surface image can be obtained. This activity is analogous to atomic force microscopy and it offers a view of magnetic force microscopy (MFM) used for larger-scale imaging.
There are a few more that we've made available, and I'll post them separately.
CREDIT: Goes to Dr. Kathleen Carrado-Gregar, Ph.D. Argone National Labs: firstname.lastname@example.org
Enjoy! - Josh
Here's one Nancy contributed to our newsletter in March 1993. It combines magnets and breakfast cereal, which should get any 2nd grader's attention:
"Money, Munchies, and Magnetism": http://chicagoacs.org/articles.php?id=42
Here's the lead paragraph:
Kids, you probably already know that iron is magnetic. In this column, we will demonstrate a way to prove that there is iron metal in two places that you have probably not ever realized: a one dollar bill and a bowl of cereal! You will need a bar magnet (chemists can use long thin stir bars), a dollar bill (or $5, $10, $20 - they all work), and a box of cereal that claims to be high in "reduced" iron (like Total®).
for the full activity, see: http://chicagoacs.org/articles.php?id=42
Here's a ChemShort that Dr. Carrado-Gregar posted in 2011, the International Year of Chemistry.
Kids, can you test for little bits of space in your own backyards? Every day, 500 tons of dust and rock from space collide with Earth. Much of this burns up in the atmosphere as ‘shooting stars’. However, particles smaller than a millimeter sometimes slip through the air without burning. These are micrometeorites. They can float through the sky as dust and fall to the ground in rain. With a powerful magnet and some luck you just might be able to find one of your own.
You’ll need a paper cup with two holes poked through the paper at the top near the lip of the cup, across from each other. Through these holes tie a loop of string about one foot long so that you have a basket. Into the cup place a very strong U-shaped or bar magnet. This is your micrometeorite collector. Bring it outside on a dry day and gently tap it over areas of ground that are dry (but that do get wet after rain) and not disturbed by people or vehicles. Good places to try might be near downspouts, areas of lawn not often used, or areas next to hiking trails.
… complete activity at http://chicagoacs.org/articles.php?id=226
Enjoy! - Josh