1. Measurements and Lab Equipment
(Obj 2:a-b; 3)

2. Measurement What is a measurement?
A measurement is a quantity that has both a number and a unit.
How are measurements used in science?
To collect data and to keep track of the amounts being used

3. Units (don’t need to write)
What is a unit?
Units are standard values
Why do we use units?
Units allow people to be able to compare data and to be consistent

4. Types of Measurements
Qualitative measurements deal with observations or “qualities”.
Quantitative measurements deal with numbers or “quantities”.

5. Types of Measurements
Label the following as quantitative or qualitative
A wooden block is 1 foot in length
A wooden block is red in color
The solution is blue
The solution is 321 mL in volume
quant
qual
qual
quant

6. Making Quantitative Measurements
A quantitative measurement should have both a number and unit.
When making the measurement you write down the known digits plus one that is estimated
In the measurement cm the 12.4 are known and the 9 is estimated

7. Measurement (don’t need to write)
Every experimental measurement has a degree of uncertainty.
The volume, V, at right is certain in the 10’s place, 10mL<V<20mL
The 1’s digit is also certain, 17mL<V<18mL
A best guess is needed for the tenths place.

8. Measurement (cont)
Three differently calibrated meter sticks are used to measure the length of a board. a) A meter stick calibrated in a 1-m interval. b) A meter stick calibrated in 0.1-m intervals. c) A meter stick calibrated in 0.01-m intervals. Measuring How many significant figures are reported in each measurement?

9. Measurement (cont) What is the Length?
We can see the markings between cm
We can’t see the markings between the .6-.7
We must guess between .6 & .7
We record 1.67 cm as our measurement
The last digit 7 was an estimate but all three numbers are still part of the measurement

10. Measurement (cont) What is the length of the wooden stick? 1) 4.5 cm

11. Lab Equipment Match the following to the proper measuring tool
Temperature
Mass
Density
Volume
Graduated cylinder
Scale/balance
Scale/balance and ruler
Thermometer
Answer Key: 1 = D, 2 = B, 3 = C, 4 = A

12. Lab Equipment
Match the following to the proper measuring tool
Beaker
Scale/balance
Hot plate
Thermometer
Answer Key: 1 = D, 2 = A, 3 = B, 4 = C