The Magnet Detectives

Science Saturdays for 2013 started off with a bang! The weather brought us 70 degrees and partly cloudy, and it was a perfect morning for being outside and having some science fun!

Our lesson this month was on materials things are made out of. There are lots of materials on earth, but only a select few are attracted to magnets - those materials have iron in them (think steels). Many kids hypothesize that all metals stick to magnets. This is a good educated guess, but it's wrong (and it's ok to be wrong at this level of science understanding - that's how we learn).

I got the idea to bury things in the sandbox from J's preschool, where they bury paper/sequence in their school playground and the kids go find "treasures" (which we cannot throw away no matter how many times they fall on the floor and the Roomba threatens to vacuum them up).

The materials I buried:

• Matchbox cars
• Tin/jar lids (ie. Altoid boxes)
• Sponges
• Aluminum foil
• Cheap Ikea baby silverware spoons
• Milk caps
• Candles
• Popsicle sticks
• Straws
• Balloons
• Marbles
• Pennies
• Bobby pins
• Paper clips
• Pipe cleaners
• Army men
• Rubber bands
• Giant metal washers
• Colored plastic chips with a metal band around them (they came in a magnet activity)

*note, I stayed away from anything sharp since burying nails in a public playground doesn't sit well with me as a mom.

As the kids dug up a treasure, they had to say what they thought it was made out of and whether or not it'll be attracted to a magnet. A good way to test would be to place the item on top of the magnet, then flip the magnet over. If the item sticks, it's attracted. If not, it's made up of a different material.

For those who were still interested in playing science after 15 minutes (seriously people, sometimes science day feels like a flash mob, but the adrenaline rush is awesome and the kids always have fun), I showed them that the magnet itself doesn't stick to cardboard, but the magnet has a field which can go through cardboard. I made up a dancing bug activity on the fly. It went over super well. All you need: a few pipe cleaners, a magnet, and a piece of cardboard. Place the magnet under the cardboard and watch your pipe cleaner bug move magically!

Big J (my husband), came up with the game, how many washers can your magnet hold. I also heard they were playing pass the washers with their magnetic wands as they ran around the playground.

One more game with magnets on playgrounds: hide the magnet. It's like hide-n-seek, only you're hiding the magnet (hopefully a larger, visible one) somewhere on the playground (preferably on a metal structure to narrow things down). Then the kids have to find it based on their knowledge of where they think it could be sticking.

Thanks for everyone who came to our fun Science Saturday. If you live in the Bay Area and would like to join us, shoot me an email using the link over to the left, and I'll add you to the email list for Science Saturdays. I try to hold them at least once a month and give at least a 5 day notice of events. They do depend on weather and our overall family's health (we love sharing, but not the flu).

**These are the magnetic wands we used: Learning Resources Magnetic Wands**

Park Science - Parallel Bar

We live in a small apartment without much wiggle room. However, we have a park nearby. This has saved my sanity on numerous occasions, but I'm a worrywart - I've always been a little bit of a chicken/scaredy cat when it comes to taking risks that could result in injury. Unfortunately for me, I have a son who has the "I can do anything" attitude of my dearest little sister (who was deemed "concussion queen" of the family and left a few dents in our elementary school floors). I've also learned if I don't let him try, I usually cause myself more grief. Luckily, playing on the playground uses a lot of science, which I'm trying to explain to J as he's learning (so he can do it right and understand "What happens when..." in a safe and controlled environment). I was also a recreational gymnast in my past, so I feel pretty comfortable spotting J as he learns.

While playing on the parallel bar (chin up bar?) the other day, J was swinging his legs. He let go before I was able to get to him, and SPLAT, he had a face full of sand and the wind knocked out of him (I'm still a big sand as a landing material proponent). He's ok and wanted to continue playing after a few snuggles.

We've been working on the only drop when your legs are perpendicular (straight up and down) from the ground and you aren't swinging. However, it's been a few weeks since we've been able to go to the park and he must have forgotten.

Here's what happens:

When you hang still, your center of mass is directly inline with your feet, making it easy to let go and land on your feet (with bending your knees, of course - and the obligatory "Tada!" after making a perfect landing).

What J did the other day:

His center of mass still wanted to be directed downward (thanks to gravity). However, with his feet still swinging backwards, he ended up with a moment (rotation) which resulted in him splat-faced on the sand. I don't recommend experimenting with this way, as it really hurts to get the wind knocked out of you, and it doesn't taste good to eat sand.

However, you might try falling a different way (in a safe environment - meaning on soft/safe landing materials - sand, gym mats, etc. - and not from very high). In my family, we come with built in cushions, so falling on our behinds is no big deal.

J demonstrates the slight forward leg swing (think opposite of the second drawing):

When J lets go in this position, he's going straight to his bottom. Please note, I would recommend a more centered position on the bar, as scraping the playground on the way down is also no fun (he didn't drop from this position). Also, if you swing too much forward, you'll end up on your back (also, probably with the wind knocked out of you) and/or hitting your head.

I might not recommend going out and seeking your own answers to this experiment, but I'm sure if you have a monkey like I do, he/she is experimenting on their own and figuring it out (physics). Now you might be able to explain why a straight drop is recommended and not to let go during a swinging motion.

P.S. My biggest fear is that J returns to the ledge after hanging and lets go with his center of mass still not all the way on the ledge, falling head first off of the playground equipment. So, yes, I encourage straight drops. Practice makes perfect (or at least a little more relaxed mommy).