Science of Magnetism

Every week, Madison (my 10-year old daughter) and I teach a 1.5-hour afterschool science club for K-2^nd graders.  Each week she helps plan the lesson and then write the blog about what we did. 

We have provided links to the books we used to sneak in some literacy.  We learned most of the science experiments and activities from Steve Spangler (awesome speaker and science guy extraordinaire).  We have included links to his science supplies, experiments, and videos.  We have also included links to our YouTube videos. These links take you away from the blog and to external websites.

Lesson 18 & 19

Science of Magnetism

See our YouTube video – Mission Magnetism: Opposites Attract 

Science Standards Addressed: Students can describe the properties of magnets.

Plus we snuck in some speaking and listening standards like asking questions, expressing ideas, following multi-step directions, and participating in discussions.

5 minutes

As the children arrived we played the songs Stuck on You, by Elvis Presley; and Magnet and Steel, by Walter Egan.

Cow Magnets

We explained that when cows are grazing, they eat EVERYTHING! They eat hay, grass, dirt, staples, little bits of bailing wire, even nails – they call it “tramp iron.” Then we showed them a super strong cow magnet. Link to COW MAGNETS.


We explained that ranchers put these magnets down a cow’s throat, so that any iron that the cows eat gets stuck to the magnet.  If this iron goes through their digestive tract it can get lodged and cause irritation and Hardware Disease, which causes cows to loose their appetite, and not gain weight (meat).  Hardware Disease also reduces milk production in dairy cows. One magnet stays in the cow for it’s whole life. Before eating snack we showed them an iron nail. We asked if THEY would ever eat such a thing?  NO WAY JOSE!

Then… we gave them some iron to eat!

We snacked on some iron-enriched cereal with prunes and bananas, which both contain iron.

 

10 Minutes

To sneak in some literacy standards, while they ate snack we read them

Gregory the Terrible Eater, by Mitchell Sharmat – a story that talks about Gregory, a goat, that would not eat anything that goats eat. He would only eat thing that we eat. So his parents took him to the doctor the doctor said to give him what he wants but add one goat food, so for dinner that night they had spaghetti but they added a shoelace too. Gregory got use to that and soon he would eat soup, and the can! In the end he ate like a goat. Buy the book.

Eating Iron

We gave the kids small boxes of iron-fortified cereal, zip-type bags, water, and a super-strong neodymium magnet. The kids first crunched up their cereal while still in it’s original bag (if you do it in the zip bags you’ll punch holes in the bag and make a big mess – I learned that little lesson the hard way).  Then they poured their cereal crumbs into the zip bag and filled it halfway with warm water.  We explained that we just did is a little bit like what happens in our body.  First we crunch up our food with our teeth when we chew, and we add saliva and digestive liquids to the crumbs, and it sits in our stomachs (zip bags) and digests for a while.

Link to Iron for Breakfast Classroom Pack


Whadda You Know
We gave each child a wand magnet and played the game.  Standing in a circle each child shared something they already knew about magnets. They knew that magnets can attract or repel each other.  They knew you can pick stuff up with magnets – metal things. They knew each one has a north pole and a south pole. The older kids knew that magnets create magnetic fields.


Magnetic Exploration
We gathered lots of metal stuff from around the school that we thought might be attracted to magnets.  Before testing it out we asked the kids to predict what they thought might happen if we brought a magnet close to the stuff and to explain their predictions. Some of the predicted that everything would be attracted to the magnet except the metal coins. Why?  Because they’d tried it before and knew money was not attracted to a magnet. Then we tested it out.  We brought the magnet close, and SOME of the metal items were attracted to the magnet.  The kids noticed that the items that were attracted to the magnet had a “silver” color and the items that were not attracted had a “gold” color (brass). 

None of the coins they collected were attracted to a magnet.  “See,” they said, “money is not attracted to a magnet.”


Magnetic Money

So, we added some coins we had gathered – from Mexico, Guatemala, Viet Nam, China, Singapore, Canada. Yes we traveled the globe – scoured the earth - looking for coins especially for this science club.


We asked the kids to predict what might happen this time and to explain their predictions. There was no agreement about what might happen. This time when we brought the magnet close – many of the coins were attracted to it. Upon closer examination the kids noticed that the coins that were not attracted to the magnet were all American coins.  So they concluded that American money is NOT attracted to a magnet.


Not so fast kids!  We asked them to look a little closer at the coins stuck to the magnet. They discovered an American penny. Wow – some of them were totally confused because they KNEW FOR SURE that pennies are not attracted to a magnet. When we asked them to explain what they had observed, some thought it was a fake penny.  The penny was actually a 1943 World War II steel penny. It was so old and dirty that it passed as copper.  We showed them some that were cleaned up – obviously NOT copper.


They had to revise their conclusion yet again!  Some money is attracted to a magnet and some is not.  It all depends if enough metals that are attracted to a magnet are used.


“So,” we asked, “what about PAPER money?”  Could a dollar bill be attracted to a magnet.  Again, we asked them to predict and explain their predictions. They all believed that a dollar bill would not be attracted to a magnet.  We asked if anyone had a dollar we could borrow.  One of them offered up a buck and we held it close to a super strong magnet, and immediately the dollar was drawn to the magnet.  We showed them this over and over.  When we asked them to explain their observation, they said there MUST be iron in the dollar.


We told them we had an idea about how they might get the iron out of the dollar bill. We waved it playfully over a blender we had filled halfway with water. You should have seen their faces! They thought we were teasing. Then we dropped the dollar bill in the blender, and their eyes bugged out even more. When we hit the “High” button they screamed!  Especially the kid who loaned us the dollar!  


As we continued making this money smoothie, we held a super strong magnet up against the blender wall. We stopped the blender and had a couple of kids come VERY close.  If they looked closely, as we removed the magnet, they could see a little spot of iron begin to fall away.  When we brought the magnet close, we could get the tiny pieces of iron to follow the magnet.  We repeated this until everyone could see for themselves. Then we poured the slurry into a zip-type bag and repaid the student who had loaned us the dollar. Repeating Bob Becker’s joke, we said – “now you don’t have to worry about cash flow!  Here are some liquid assets!” They didn’t really get the joke. Sometimes the jokes are just to crack ourselves up.  In the zip-type bag it was even easier to see the little specks of iron.

Eating Iron, cont.

By this time, the cereal in the bag was completely softened – a gross, brown, soupy slurry.  We placed our magnets on the bag, and flipped the bag over so the magnet was on the bottom.  We sloshed it around a little bit and flipped it back over. Just like the dollar, we could clearly see little bits of iron following our magnet.  Sometimes seeing ISN’T believing.  Many of them could still not believe that they EAT iron. This fun experiment is a “physical” separation of iron from the cereal. So we talked a little bit about the difference between physical and chemical changes (even though that is a 4^th grade standard). 

Fall into the GAP!

We gave the kids these floating magnetic rings with a magnetic stand. We challenged them to see who could create the biggest gap. After some experimenting, they discovered that if they put several magnets on the stand with like polarities (north) facing up and then flipped the next magnet over so that north faced down – it created a stronger repulsion – a bigger gap.


Playing the Field
We had fun exploring and playing with magnetic fields. We played with magnetic field viewing film. We gave them some little plastic boxes filled with iron filings and let them actually see the magnetic fields.

We made field viewers by cutting a whole in a shoebox and covering the whole with a transparency sheet of plastic.  We sprinkled iron filing on top and put a bar magnet below it.  We could see the magnetic field lines “leaving” the north pole of the magnet and entering the south pole. We let each child pick either an empty 1L plastic bottles or and empty Baby Soda Bottle, and pour iron filings into them for a magnetic field viewer they could take home with them.

In Search of North

We hung a wand magnetic by a string and let it hang freely. Eventually it stopped moving. We wrote “north” on the side of the magnet that was facing north (we knew which way was north, plus we had a compass to make sure). We wrote “south” on the side facing south – and - tada - we created our own compass.

Fly Like a Butterfly

We make little paper butterflies and taped them to a paper clip. Then we tied a piece of fishing line to the paper clip and taped the other end of the fishing line to the table. Then using our wand magnets we made our butterfly illusions. Since the fishing line is almost invisible, it looked like our butterflies were flying!

Magnetic Paint – the poor man’s ferro fluid!

Our grand finale’ was so awesome, we forgot to take pictures.  You’ve gotta try this. There were lots of “Oohs” and “Aahs” from the kids and from the parents arriving to pick up their kids!

We poured some magnetic paint into a pie pan. Then we set the pie pan on a cheap card table. We then placed a super strong neodymium magnet. Link to neodymium magnet. 

under the card table directly under the pie pan. Warning: Don’t bring the super strong magnet above the card table or near the paint because the paint will fly right out of the pan – onto the magnet – which will be a huge mess!  With the magnet under the table and directly under the pie pan, we moved the magnet around. The iron in the paint poofs up and lines up with the magnetic field. As you move the magnet around, well – it’s a little freaky – like something that is strangely alive. You can see how it looks on our YouTube video!