1. The Importance of Measurement
Chapter 3

2. Qualitative Measurement
Types of Measurements
Qualitative Measurement
Measurement that gives results in a descriptive, nonnumerical form.
“This person feels hot, it might have a fever.”
Quantitative Measurement
Measurement that gives results in a definite form, using numbers and units.
“This person’s temperature is C.”

3. Uncertainty in Measurements
Difference between Accuracy, Precision and Error.
Accuracy
It is a measure of how close a series of measurements comes to the actual (true) value.
Precision
It is a measure of how close a series of measurements are to one another.
Error
It is the difference between the accepted value and the experimental value.

4. Good Accuracy and Good Precision

5. Poor Accuracy, Good Precision

6. Poor Accuracy, Poor Precision

7. Error and Percent Error Error
Error = Exp. Value – Accept.Value
Percent Error
Exp. Value – Accept Value
% Error = x100
Accept Value

8. Temperature Temperature It determines the direction of heat transfer.
It measures the average kinetic energy of particles in matter.
Almost all substances expand with an increase of temperature and contract as the temperature decreases. Water is an exception.

9. Temperature Scales There are three temperature scales
Celsius Scale: Based on the freezing and boiling point of water at standard pressure (sea level)
Freezing point of water = 0 0C
Boiling point of water = 100 0C

10. Temperature Scales
Kelvin Scale: This scale reflects the relationship between temperature and kinetic energy.
There are no negative temperatures
Zero point in the Kelvin scale is also known as the absolute zero. Particles of matter at this temperature have no kinetic energy.

11. Conversions between 0C and Kelvin
To convert from 0C to Kelvin
K = 0C + 273
To convert from Kelvin to 0C
0C = K – 273

12. Temperature Conversions
Convert C into Kelvin.
Convert 300 K into 0C.

13. Temperature Conversions
Fahrenheit to Celsius
0C = (0F -32)/ 1.8
Celsius to Fahrenheit
0F = (1.8 x 0C) + 32