Scientific Notation -Scientists often work with very large or very small numbers -For example light travels at 300,000,000 meters per second -On the other hand a snail on average travels about meter per second Scientific Notation is a way of expressing a number between 1 and 10 and a power of 10!!!

Scientific Notation Example: 300,000,000 is written in scientific notation as 3.0 X 10 The exponent 8 tells you that the decimal point is really 8 places to the right of the # 3 For numbers less than one they will have a negative exponent Example: is written as 8.6 X 10 The negative 4 exponent tells you how many places to the left 8.6

Scientific Notation When multiplying numbers in scientific notation, you multiply the numbers that appear before the multiplication signs and then ADD the exponents Example: To calculate how far light travels in 500 seconds, you multiply the speed of light by the number of seconds -Look at dry erase board!!!

Example ( 3.0 X 10 m/s) X (5.0 x 10 s) = 15 x 10 m = 1.5 x 10 m

Scientific Notation When dividing numbers written in scientific notation, you divide the numbers before the exponential terms and subtract the exponents Example: To calculate how long it takes for light from the sun to reach Earth, you would perform division -Look at dry erase board

Metric Prefixes It indicates how many times a unit should be multiplied or divided by 10 Figure 15 on page 17 -Example: You can write second as 9 milliseconds or 9 ms 9 ms = 9/1000 seconds = seconds

Metric Prefixes Conversion factor -It is a ratio of equivalent measurements that is used to convert a quantity expressed in one unit to another unit

Limits of Measurement Precision -Is a gauge of how exact a measurement is -Example: -Analog clock versus digital clock -Digital clock has more significant figures -Significant figure is all the digits that are known in a measurement, plus the last digit that is estimated

Limits of Measurement Accuracy -Is the closeness of a measurement to the actual value of what is being measured -Example: - Suppose a digital clock is running 15 minutes slow, although the clock would remain precise to the nearest second, the time displayed would still be wrong

Measuring Temperature Thermometer is a instrument that measures temperature, or how hot an object is Two main temperature scales -Farenheight and Celsius °F to °C, Deduct 32, then multiply by 5, then divide by 9 °C to °F, Multiply by 9, then divide by 5, then add 32

Measuring Temperature The SI unit for temperature is Kelvin (K) 0 k or 0 Kelvin refers to the lowest temperature that can be reached -In Celsius it is °C -To convert between Kelvins and degrees Celsius, use the following formula K = °C + 273