Monday, February 08, 2010

Science Projects

Hip hip hooray! I just finished my last science project of the year and sent it off to school with Afton. Kirkham's was due last Friday and Heath's was due the Wednesday before that. What a relief it is to have finished these three projects. We have been worrying over and studying about and working on these science projects since before Christmas and we learned a lot in the process.

Heath's project question was "What battery size works best for spinning the coil on a small electric motor". To figure this out he first had to build a small magnet coil motor. That turned out to be quite an experiment all in itself. His project question should have been "Can a 13 year old properly read and follow instructions", "Can an 8th grader write a complete project shopping list by himself" or "How quickly can one boy drive his mom crazy". Finally after MANY trips to the hardware store, the other hardware store, Target, Radio Shack and the hobby store was he able to complete the motor.

All the hard work and frustration over the motor that wouldn't go dissipated quickly when the motor got spinning. Then he had to test his hypothesis that the largest battery, a lantern battery, would spin the motor the best (fastest and most consistently). That was the fun part! He methodically tested the batteries: AAA, AA, C, D, 9V and lantern sizes. The spinning coil was mesmerizing to watch and it was so fun to see it go slower or faster or totally out of control depending on the battery it was hooked up to. He proved that his hypothesis was incorrect: the lantern battery spun very quickly but it was inconsistent in it's speed and sometimes flew off the supports because it was going too fast. He found the 9V to give the fastest and most consistent spin therefore it was deemed "the best".

Kirkham wanted to know "The fastest way to put out a kitchen grease fire". This was a follow up to his science project last year "Slow burning fabrics" in which he set out to determine if the weight of the fabric was a good indicator of a slower ignition time; he found no correlation. This year too he had some unexpected results.
In his research he found four ways that were suggested for putting out a grease fire in the kitchen: putting a lid over the fire, putting a wet rag over the fire, throwing flour on the fire or throwing baking soda on the fire. He set out to discover which way was most effective. To find out which was most effective however, he had to first start a grease fire which turned out to be harder than we thought it would be. We had to do some more research about smoke points, flash points and fire points of different oils and greases and had to determine which would be the safest grease/oil to use with the lowest fire point. We decided on Olive oil.

I sacrificed a pot from the kitchen. Dave sacrificed a propane camp stove and his propane torch. The boys set out on their adventure with fire with an audience of family and friends. Kirkham assigned Heath to hold the torch over the oil which was sitting over the burning camp stove. Kirkham prepared to extinguish the fire. Afton recorded his results and I took pictures. The pot lid put out the fire but if it was removed from the pot in under 15 seconds the flame would reignite--not good! The wet rag also put out the fire but if the aim was off and it only got over half the pot the towel would start on fire--not good! The flour made the 6" fire leap to 2.5 feet--NOT GOOD!!!!! The baking soda put out the fire instantly--very good! So if you ever have a fire in your kitchen throw baking soda on it quick!

Afton's science project "Battle of the paper towels" was the quickest and easiest project of all and gave us some very useful results. She and her friend Breeanna tested the absorbency rates of four brands of paper towels. They tested Bounty, Viva, Kirkland(Costco) and Buyers Value (generic). They hypothesized that Bounty would absorb the most because they trusted the Bounty commercials.


The process was very easy. First they made sure that each square of paper towel measured the same and then they folded them in half the long way. They put 1 cup of water into a 9x13 glass dish and placed the paper towel on top. When the towel sunk to the bottom (was completely full of water) they quickly lifted it out of the water and placed it into a separate bowl. The leftover water in the 9x13 dish was then poured into a graduated measuring cup and measured. They found that each sheet of Bounty collected 5 tablespoons of water! An equal size sheet of Kirkland absorbed 4 T, Viva absorbed 3 T, and Buyers Value collected a whopping 2 Tablespoons. So if you've got a big spill you can count of Bounty to collect up to 1/3 cup of liquid per sheet!

Now I think I'll need to do a strength and durability test on the paper towels so I can do a complete cost analysis which will determine "Which paper towel gives you the most for your money". Maybe that can be next years science project.

3 comments:

  1. I love their project topics! Ah...boys, fire and mechanical things. That made me laugh. I would love to find out what paper towel was really the best buy.

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  2. I too am glad that the whole science fair thing is D O N E. Jayson decided to build a crystal radio and then test to see if antenna length had anything to do with the successfullness of receiving the sound radio waves. Lo and behold, length does matter. He measures antenna length in increments of 20 feet and determined that anything over 80 feet of wire produced sound that was audible with an ear receiver. It took us FOREVER to find all the required pieces. But that was part of the journey too. The bummer thing was that it had to be turned in almost two weeks early because of our vacation. It was done and he really had a great time learning all about it.

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  3. how fun! Thank Afton, I've always wanted to do that experiment. And the boys... very cool!

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