# CeAnn Chalker Patrick Chalker

## Presentation on theme: "CeAnn Chalker Patrick Chalker"— Presentation transcript:

CeAnn Chalker ceann@chalker.org Patrick Chalker patrickchalkerso@gmail.com

Students will make: Metric Estimations then Metric Measurements on identical objects

* Mass * Volume * Density * Area * Force * Distance * Time * Temperature

* Students rotate between 15-30 stations for each of the two parts of the event * Supervisors furnish all pencils, paper, and measuring devices * Teams may bring non-programmable calculators for the Measurement Part only. * Property to be estimated/measured and Units of Measurement will be given at each station.

* Approximately 30 seconds for each station * All answer recorded on form provided by Event Supervisor * Answer form MUST be turned in before Measurement Part begins * Students may not use any kind of measuring device (fingers, pencils, clothing, paper, etc.)

* Students may not Touch or Feel any objects unless specified in directions * NEW!!! Students MUST be allowed to “heft” an object if the mass is to be estimated.

* Approximately 60 seconds per station * All answers recorded on new form provided by Event Supervisor * Measurements are made using the instruments supplied at each station * All objects will be measured by the Event Supervisor prior to the competition using the same instruments the students will use

* To receive points, 3 requirements * Proper Resolution * Estimated digit Appropriate for the Instrument * Proper Unit of Measurement Ex. – Answer should be 17.25 grams or 17.25 g on a standard Triple Beam balance Wrong answers would include – 17.2 grams, 17.2 g, or 17.25

* Direct Measurements - not involving calculations, readings directly from an instrument (e.g. length, volume, mass, etc.) * Calculated Measurements - measurements that require mathematical calculation to achieve (e.g. calculating the density of an object, height using triangulation, surface area, velocity, etc.).

* Students record measurement to +/- 3 of the estimated digit of the instrument’s resolution. * Direct Unit Conversions are considered Direct Measurements.

* The smallest actual graduation or markings on the instrument

* A rock has a mass of 56.54g. Using a triple beam balance to find that mass. * A line on the floor is 187.43cm. Using a meter stick to measure the line a student adds 100cm to 87.43 cm to come up with 187.43cm

Ruler has the smallest resolution of 1 mm * Width of object #1 - Measurement of 209.3 mm * Answers between 209.0mm - 209.6 mm would be correct Triple Beam Balance has smallest resolution of 1/10 th of a gram * Mass of rock – Mass of 37.26 grams * Answer 37.23 grams – 37.29 grams would be correct

* Students take direct measurements and make mathematical calculations obtain the correct answer. * More difficult to obtain exact answer * Various points are awarded for answers within.5%, 1%, and 2% of the correct value.

Surface Area * A rectangular box with dimensions 10.62 cm x 4.63 cm x 4.63 cm. To calculate the surface area 2(4.63x4.63) + 2(4.63x10.62) + 2(10.62x4.63) = 42.8738 + 98.3412 + 98.3412 = 239.5562 cm 2 * A circle with the diameter of 9cm, the area of that circle is 3.14159 x 4.5 2 =63.6171975 cm 2

* Both parts (Estimation and Measurement) are rated on accuracy * Rankings are the highest combined score * Three separate methods of scoring are used

Points based upon the percentage of the correct value for each station * 5 pts – Answers within 5% * 3 pts – Answers within 10% * 1 pt – Answers within 20%

* 5 pts – Answer expressed to the instrument's resolution +/-3 of the estimated digit * 0 Pts – All other Answers

Points based upon the percentage of the correct calculated value for each station * 5 pts – Answers within 0.5% * 3 pts – Answers within 1.0% * 1 pt – Answers within 2.0% * 0 pts – All other answers

* Break everything down to the fundamentals * Useful Formulas * Finding new things to measure * Conversions and units

* Comparing size and mass to known objects * Estimating time by average * Crazy (but measureable) stations

* Measuring irregularly shaped objects * Massing something on an open hand * Using a triple beam balance under time constraint * Items that seem easy but are very difficult * Approaching measurements in the same way EVERY TIME

* Practicing measuring with time * Coaching confidence (and a bit or arrogance) * Teamwork, dividing the workload * Mental math

* Put school name and team # on EVERYTHING! * Put labels for units on EVERYTHING! * Look at the measuring tool first, and then the object to measure second. * Check to see if measuring devices are zeroed or in need of zero-ing.

This is just a sampling of formulas students should know, there are many more to learn. * F=ma, Force = mass x acceleration * A=∆V/∆T (Acceleration = change in Velocity divided by Change in time) * A=(V 2 -V 1 )/(T 2 -T 1 )

* SA = πr 2 + πrl (surface area of a cone) * SA = 2ab + 2bc + 2ac (surface area of a rectangular prism) * Surface Area of a Sphere = 4 pi r 2 * Surface Area of a Cylinder = 2 pi r 2 + 2 pi r h * g=-9.81 m/s 2 (Earth’s gravitational constant) * 1 N = 1 kg (m/s 2 )

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