Kotys Dad............

[maverick2112]

Can you help me with a couple problems.......How would you answer these????

1. Do you have any hints you could give a teacher whos wishes to teach metrics to students who are not familiar with the metric system?

2. If you were given an egg how would you have your students find the volume of it? What do you feel you need to know in order to do this? Be specific.

 

[Nosigar]

If you don't mind my bumping in here, I'd do the following:

1- Don't exactly understand the question, but if you want to explain the system just tell them that metric system is much easier mathematically to calculate and go between sizes. Basically it's all a decimal system. 100 centimeters is a meter, 1000 meters is a kilometer. 1000 grams is a kilogram, etc. Theres' no need for any fancy multiplication such as how many quarts in a gallon or how many inches in a yard.
Also, other composed units such as Power, force, pressure, etc. are much more easy to work with when making calculations (1 Newton is kg/m x s2) same for Pascals, joules, hertz, etc.

2- For the volume of an egg, fill a measuring cup with water, put the egg in and see how much the water line rises. Then you will have the volume. Since I know of no mathematical function that would describe the shape of an egg, it would have to be done experimentally.

 

[KotysDad]

Re: Kotys Dad............

Mav,

Outside of using calculus, Nosigar has the best method I have ever come across for measuring the volume of an egg. You need something called a "graduated cylinder" to measure volume. You put water in the cylinder and record the initial amount. Submerse the egg (making sure there isnt too much water that it overflows) then record the new water level. The difference is the volume of the egg.


As far as the metric system, Nosigar again has the right idea. Here is what I would do, and this is just one teacher's opinion.

1. Point out the benefits of metric measurements.....Decimal based, no weird conversions, etc... Distance is measured in meters, mass in grams, etc...

2. Acquaint them with the prefixes before you actually get into the measurements. Make little word games like deca = ten so 10 dents would be a decadent. Stuff like that. This exercise actually works better with beginning physics students who need to know prefixes like terra- (which if i recall is 10 with 9 zeros)......then you do terrapins and stuff like that.

3. Totally immerse them in it. Get measuring sticks, balances, etc...that only have metric values. Have them measure or weight everything in sight....their hands, the window, floor tiles. etc.....

4. After a few days of immersion, bring in strange objects and have them estimate its length, width, or weight. They usually get pretty close with their guesses.

5. Try to avoid any talk whatsoever about converting meters to feet or yards, or whatever. Dont use measuring devices that have both feet and meters, or pounds and kilograms, etc....If they focus only on metrics, they wont try to convert to US measurements at all.

 

[maverick2112]

Thanks guys...............you are a big help..........very much appreciated..................

 

[Nosigar]

No problem Actually if you want to tell them a story you could use the volume experiment.
As I told this story as a kid, there was in ancient greek times a gentleman by the name of Arquimides who had a problem to solve.

The king at the time had ordered a local artisan to make him a gold crown and had given him a certain amount of gold to be melted. He wanted to know gow to make sure that the now finished crown was made of of only gold and not mixed with other less valuable metals.

They knew the weight of the gold prior to giving it to the artisan. They also knew the initial volume since the gold came from coins and objects with shapes that make it easy to calculate the volume (i.e. a coin is a cylinder so it's pi x r-squared x the height). But the crown is an irregular shape so there's no constant that enables its volume caculation.

One day while Arquimides was in a bath he saw how the water level rose as he sank into the tub. Then he saw that the volume of water risen was always the same and deduced that was equal to the volume of his body. Having solved the problem he then ran out into the streets naked screaming EUREKA! EUREKA!

He had found the solution to the variable in his problem. The crown could weigh the same as the amount of gold coins given to be melted, but if there was another element such as copper or iron mixed in these weigh less and therefore would need more total volume to equal the weight needed. So if the crown now had more volume than the volume of all the coins, the artisan had surely taken some of the gold and replaced it with cheaper element.