1. Chapter 2
Measurement

2. Description and
Measurement
2.1

3. A. Measurement A way to describe the world with numbers
Answers questions such as how much, how long, or how far
Can describe cost ($), distance, volume, mass, speed
In scientific endeavors, scientists rely on measurements instead of opinions
Why is it important for doctors to know how much the heart pumps blood?

4. When would it be important to measure air?
Air available inside of an airplane
Air inside of a firefighter’s airpac
Air inside of a rocket ship for astronauts

5. Why is it important for certain events, like swimming to be measured?
Events can be measured
Why is it important for certain events, like swimming to be measured?
2016 Summer Olympics, Michael Phelps swam the 100m butterfly and won his 7th gold medal for a singles event by a hundredth of a second
Michael Phelps – 50.58
Milorad Cavic –

6. B. Estimation To give a rough measurement of an object
Usually used when you don’t have the right tool to make an exact measurement
Can use your knowledge of the size of something familiar to estimate the size of a new object
A skill based on previous experience and is useful when you are in a hurry and exact numbers are not required
A valuable skill that improves with experience, practice, and understanding

7. When do you estimate? Come up with one on your own.
How much bread a restaurant warms up for the different tables coming in.
How many papers to print off for a meeting.
How much money you need for a trip.
How much ingredients to put in a recipe.
How much dog food to put in the bowl.

8. D. 1. Precision
One way to evaluate measurements is to determine whether they are precise
Precise – a description of how close measurements are to each other
Precision is used when discussing the number of decimal places a measuring device can measure
A wall clock or a clock with a second hand
Making a measurement and getting the same result each time or your friend measuring the same thing and getting different answers each time

9. d. 2. Accuracy
When you compare a measurement to the real, actual, or accepted value
The second hand on a watch will give a precise time (7:38:10 p.m.) but it’s not accurate if it is 25 minutes behind
“But officer, my speedometer says I’m only going 40?!”

10. d.3. Rounding a measurement
Not all measurements require an exact measurement
Rounding rules
Look at the number to the right of the place you are rounding
If it is 0-4, it stays the same
If it is 5-9, it goes up one
The length of the walk to school.
You could measure it to nearest millimeter
But only would need to know to the nearest meter or tenth of a meter and still be accurate such as 2,348.50

11. D. 4. precision and number of digits
Let’s say you have a bag of M&M’s and you want to share it with your friends.
There are 4 of you and 30 M&M’s…
Each of you will get 7 M&M’s but there are 2 left over?
Would you bother to cut the 2 M&M’s in half so everyone gets exactly the same amount or would someone just eat the 2 extra M&M’s?

12. d.5. Using precision and Significant digits
Significant digits or figures – the number of digits that truly reflect the precision of a number
Digits other than zero are always significant
Final zeros after a decimal point ( g) are significant
Zeros between any other digits ( g) are significant
Zeros before any other digits ( g) are NOT significant
Zeros in a whole number (1650) may or may not be significant
An exact number, such as the number of people in a room or the number of meters in a kilometer, has infinite significant digits