2.  There are two types of measurement  Quantitative measurements have a definite form and are usually expressed as numbers with units. ▪ E.g. 3.05 grams, 12 liters, 4.5 grams/ml  Qualitative measurements are descriptive and have no numbers involved. ▪ E.g. It gave off a “reddish gas”, It had small bumps

3.  Measurements can be either direct or derived.  Direct measurement can be taken straight from an object. ▪ E.g. The length of an object in meters  Derived measurements must have a mathematical expression performed using several direct measurements ▪ E.g. The volume of an object is length x width x height

4.  Density is a very important derived measurement.  Density = Mass Volume Density is an example of an intensive property because it does not depend on how much of the object you have on hand.

5.  How do you know if your measurement are true or not?  Accurate measurements are measurements that are very close to the true value of a measurement.  Precise measurements are measurements that are consistent, but not necessarily close to the true value.  The goal is to have measurements that are both accurate and precise.

6.  Think of a dart board. http://practicalanalyst.com/wp-content/uploads/2007/12/accuracy.jpg

7.  The reliability of a measurement is expressed by the number of significant figures that are present.