Chapter 3: Scientific Measurements Notes: 10/16, 10/18, 10/20

3.1: Qualitative and Quantitative Measurements Main Point: You take measurements all the time and there are two kinds of measurements. A. Qualitative: Give results in a descriptive, nonumerical form - Example: The sick person forehead feels warm B. Quantitative Measurements: Give results in the form of a number and a unit - Example: The sick person temperature is 101 degrees Fahrenheit.

Scientific Notation Main Point: In our class, we will deal with very large and very small numbers so we need a way to abbreviate it. 3. Scientific Notation: A number written as the product of two numbers: A coefficient and 10 raised to a power. For example 36000 = 3.6X104 4. When you multiply scientific notation, multiply the coefficients and add the exponents (when dividing, divide and subtract) For example: 5. When you add/subtract scientific notation numbers you must first adjust the exponents to make them the same. Then solve.

3.2: Uncertainty in Measurements Accuracy: Measure of how close a measurement comes to the true value. Precision: Measure of how close a series of measurements are to each other (reproduce measurement) Accepted Value: A value measured in a lab Error = Accepted Value – Experimental Value Percent error = error divided by accepted value times 100 Significant figures include all numbers that are KNOWN and one estimate Example: I weigh 181 pounds

Significant Figure Rules! In measurement contain all KNOWN number and one ESTIMATE 1) All non zeros of measurement are significant figures 2) All zeros between non zeros of measurement are significant figures 3) Zeros at beginning of measurement are not significant 4) Zeros at end of measure are only significant if there is a decimal