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Re: Metric Mastery B

Posted: February 24th, 2014, 5:31 pm
by ThatRoboGuy
EVERYONE will be using the same scale to measure. So it shouldn't matter.

Re: Metric Mastery B

Posted: February 24th, 2014, 7:33 pm
by hscmom
ThatRoboGuy wrote:EVERYONE will be using the same scale to measure. So it shouldn't matter.
Yes, they are all using the same scale BUT it is possible for the scale to get intentionally or unintentionally knocked off zero. Mentioning it to the supervisor lets him know about it. Perhaps he checked all equipment before the start of the hour and he is certain it was zero. Perhaps he knows that the scale is wacky and won't properly zero. But he needs to be told. Students using a scale that is not zeroed correctly (but was previously) will not get an accurate measurement (and therefore lose points).

Also, it is important that the measuring equipment be accurate. The supervisor is to measure all objects with the same measuring devices that the students will use, before the competition. If the device is inaccurate, then (especially with lighter, smaller, shorter, etc. objects) it is possible that students will lose points because their accurate estimate is not within 5% of the measured mass/length/etc. Conversely, an inaccurate estimate can appear to be dead on if the scale/ruler/whatever is inaccurate too.

I told my metric kids to check that scales are zero and immediately report it.

Re: Metric Mastery B

Posted: March 1st, 2014, 6:39 pm
by homesciencenerd
it is just better to ask the judges if you or they can zero the scale

Re: Metric Mastery B

Posted: March 2nd, 2014, 5:15 am
by hscmom
homesciencenerd wrote:it is just better to ask the judges if you or they can zero the scale
Didn't know you were on the forum.

Re: Metric Mastery B

Posted: March 2nd, 2014, 6:04 am
by Unome
Does anyone know any good methods for estimating mass?

Re: Metric Mastery B

Posted: March 5th, 2014, 12:12 pm
by hscmom
Unome wrote:Does anyone know any good methods for estimating mass?
IMO, Mass is more difficult than length and volume. One very simple thing we did is to collect different household things (a can of soup, a pack of index cards, a shoe - you get the idea) and stick them on the scale and write the mass in Sharpie.

Then practice. Heft your mass the same way each time (in other words, if you don't rest your hefting elbow on a table today, don't rest it on there tomorrow).

Re: Metric Mastery B

Posted: March 23rd, 2014, 9:21 pm
by awesome90220
I really should know this, but during measurements for things like mass and volume, how do you do the decimals on that? say you measure it to be 91.1 mm, 32.0 mm, and 28.7 mm, would you just multiply them all and stick that in as your answer?

Re: Metric Mastery B

Posted: March 24th, 2014, 8:00 am
by treeling
awesome90220 wrote:I really should know this, but during measurements for things like mass and volume, how do you do the decimals on that? say you measure it to be 91.1 mm, 32.0 mm, and 28.7 mm, would you just multiply them all and stick that in as your answer?
No. Remember to use sig figs.

Re: Metric Mastery B

Posted: March 24th, 2014, 8:18 am
by hscmom
treeling wrote:
awesome90220 wrote:I really should know this, but during measurements for things like mass and volume, how do you do the decimals on that? say you measure it to be 91.1 mm, 32.0 mm, and 28.7 mm, would you just multiply them all and stick that in as your answer?
No. Remember to use sig figs.
Yup. The sonic website has the SO policies on sig figs. And, remember to multiply units!

Re: Metric Mastery B

Posted: April 14th, 2014, 5:45 am
by Pele
mrburrito wrote:
roz_m wrote:Does anyone have any good recourses for metric mastery? I have basic information but I want to get more into the history of the metric system.
Yes, rulers and triple beam balances. :D
Calipers usually come up on the tests too. Also, graduated cylinders would be useful.