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Learn about temperature conversion between Celsius and Kelvin scales, explore absolute zero, and find out how to calculate percent error in scientific data. Understand the significance of percent error in comparing experimental results accurately.
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Topic: Temperature & Percent Error • Do Now: Look through the reference table, where would you look if… • you forgot what value nano hold • you couldn't’t remember what quantity a Kelvin measured • you needed the equation for density
Temperature Scientifically speaking … Temperature is measure of average kinetic energy of particles in system Scientists use the Celsius and Kelvin scale Where would you find how to convert between the two?!?!
Conversion formulas How can we convert from one temperature scale to another? K = °C + 273 (more precisely 273.15) °C = K – 273 [F = (9/5 °C) + 32]
Absolute Zero • Zero on the Kelvin scale: point at which all matter is said to stop moving
World’s Record Cold Temperatures(note: absolute zero = -273˚C) Date ˚F ˚C World (Antarctica) Vostok II 7/21/1983 –129 –89 Verkhoyansk, Russia (Siberia) 2/7/1892 –94 –70 Asia Oimekon, Russia 2/6/1933 –90 –68 Greenland Northice 1/9/1954 –87 –66 N.A. Snag, Yukon, Canada 2/3/1947 –81 –63 U.S. Prospect Creek, Alaska 1/23/1971 –80 –62 U.S. (other than AK) Rogers Pass, Mont. 1/20/1954 –70 –56.5
accepted value use absolute value – answer always positive Percent Error measured value – accepted value x100%
Student A (g/cm3) Student B (g/cm3) Student C (g/cm3) 1.54 1.45 1.72 Average after 3 trials Data table Students were asked to find the density of sucrose [Sucrose has a density of 1.59 g/cm3] Calculate the percent error of each student to the correct sig figs 8.18% 3.14% 8.81%
Advantage of % Error • Makes it easier to compare data, especially if comparing data from different trials