1. Measurement in Science

2. DESCRIPTION AND MEASUREMENT

3. Measurement
Measurement- a way to describe objects and events with numbers
Answers questions like how much, how long, or how far
Every measurement has a number and a unit of measure

4. How do measurements describe events?
Example:
In the 2000 summer Olympics, Marion Jones of the United States won the women’s 100-m dash in a time of
100 meter long run
10.75 second time

5. Estimation What is estimation? How do you estimate measurements?
When is estimation used?

6. What is Estimation?
Estimation-a method used to guess the size of an object
Can be used if the item you need to measure is too large, you don’t have a way to measure the item, or if you are trying to guess the measurement of an object in comparison to another.

7. How do you estimate measurements?
You can compare objects to estimate a measurement.
Example: The tree in the figure is too tall to measure.. You can estimate the height of the tree by comparing it to the height of the person. The tree is about twice the height of the person. If the person is about 1.5 m tall, the tree must be 2 x 1.5 m, or about 3 m tall.
Estimate measurements often use the word about
Reading Check #1

8. When is estimation used?
Estimation is used…
When an exact measurement cannot be made
To check that an answer is reasonable
Example:
A friend tells you that she thinks she is 5’6”. You are 5’7”, so if you stand next to her, she should only be about 1” shorter than you. When she stands next to you, you estimate that she is at least 3” shorter. Your estimation shows that her height of 5’6” wasn’t reasonable.
Reading Check #2
Reading Check #3

9. Precision
Precision- describes how close measurements are to each other
Example:
Suppose you measure the distance from home to school four times. Each time you get 2.7 km. Your neighbor measures the same distance four times. He measures 2.9 km two times and 2.7 km two times. Your measurements are closer to each other than you neighbors, so your measurements are more precise.
Instruments used to measure today are much more precise than those used in the past.
Reading Check #4

10. Accuracy What is accuracy? What makes a good measurement?
How do you round a measurement?
Some measurements are not precise?
What are significant digits?
How do you calculate with significant digits?

11. What is Accuracy?
Accuracy- the closeness of a measurement to the true value
Example:
Suppose you measured the length of your shoelace twice. You measured 12.5 cm and 12.3 cm. Your measurements are PRECISE, but if the actual length is 13.5 cm, your measurements are not ACCURATE.

12. What makes a good measurement?
A good measurement must be…
Precise AND Accurate
A precise measurement is not always a good measurement
Example:
A watch with a second hand may be more precise than one without, but if it is set at the wrong time, it is not as accurate as a clock set at the right time.

13. How do you round a measurement?

14. Practice Rounding Round 234 to the nearest hundred.
Identify the rounding digit (2)
Look at the digit to the right (3)
If that number is less than 5, keep the rounding digit the same. If it is 5 or more, change the rounding digit to one number higher. (3 is less than 5)
The answer is 200

15. Practice Rounding Round 261 to the nearest hundred.
Identify the rounding digit
Look at the digit to the right
If that number is less than 5, keep the rounding digit the same. If it is 5 or more, change the rounding digit to one number higher.
The answer is ____________

16. Practice Rounding Round 5.1837 to the nearest hundred.
Identify the rounding digit
Look at the digit to the right
If that number is less than 5, keep the rounding digit the same and remove all other digits to the right. If it is 5 or more, change the rounding digit to one number higher and remove all other digits to the right.
The answer is ____________
Reading Check #5

17. Some measurements are not precise.
If a measurement doesn’t need to be precise, you can round your measurement.
Example:
Suppose you want to divide a 2L bottle of soda equally among 7 people. When you use a calculator to divide 2 by 7, you get You can round this number to 0.3. You pour a little less than 1/3L of soda for each person.

18. What are significant digits?
Significant Digits- number of digits that show the precision of a number
Example: 18 cm has two significant digits: 1 and 8.
All non-zero digits are significant digits.
Sometimes zeroes are significant and sometimes they are not.
Rule
Example
Number of Significant Digits
Always Significant
Final zeroes after a decimal point
4.5300 5
Zeroes between other digits 7
Not Significant
Zeroes at the beginning of a number 2
May be Significant
Zeroes in whole numbers
16,500
3 or 5
Reading Check #6

19. SI UNITS

20. The International System
Scientists created the International System of Units, or SI
SI- a system of standard measurement that is used worldwide
Units in the SI system represent multiples of ten

21. Prefix
Meaning
Multiply by:
Giga-
One billion
1,000,000,000
Mega-
One million
1,000,000
Kilo-
One thousand
1,000
Hecto-
One hundred
100
Deka-
Ten 10
UNIT 1
Deci-
One-tenth
0.1
Centi-
One-hundredth
0.01
Milli-
One-thousandth
0.001
Micro-
One-millionth
0.0001
Nano-
One-billionth
1 decimeter= ______________m
10 dekameter = _____________m
5 kilometer= _____________m 40 hectometer= ______________m
764 millimeter m= ______________m
7 kilometer= _________________m
Reading Check #1

22. SI Base Units Length- Meter (m) Mass- Kilogram (kg) Time- Second (s)
Temperature- Kelvin (K)
Volume- cm3

23. Length Length- the distance between two points
Meter (m)- the SI unit of length
About as long as a baseball bat
Smaller units are used to measure shorter lengths more precisely
Millimeters
Centimeters
Larger units are used to measure longer lengths more accurately
Kilometer

24. Which unit of measure would be best to use to
measure the following items?
Millimeter or Meter?
Decimeter or Megameter?
Centimeter or Meter?
Kilometer or Meter?

25. Volume
What is volume?
How can you find the volume of ice cubes in water?

26. What is Volume? Volume- the amount of space an object fills
For a rectangular object, use the formula…
Volume = length x width x height
V = l x w x h
Reading Check #2
Reading Check #3

27. How can you find the volume of ice cubes in water?

28. Mass What is mass? Mass vs. Weight
How much would you weigh on other planets?

29. What is Mass?
Mass- an object measures the amount of matter in the object
The mass of a paper clip is about 1 g.

30. Mass vs. Weight Mass and Weight are NOT the same!
Mass is the amount of matter in an object
Your mass on the moon would be the same as on Earth
Weight is a measure of the gravitational pull on the matter in an object
Your weight depends on gravity, so you would weight much less on the moon
Reading Check #4

31. How much would you weigh on other planets?
The SI unit for force is the Newton (N)
If you weighed 75 lbs. on Earth, or 332 N…
On Mars, you would weight 126 N.
On Jupiter, you would weigh 782 N.
Your mass would always be the same!
Reading Check #5

32. Time Tells how long it takes an event to happen
Seconds (s) – Minutes (m) – Hours (h)

33. Rate
Rate- the amount of change in one measurement that takes place in a given amount of time
To find rate, a measurement is divided by an amount of time
Common Rate:
Speed= distance/time
Examples:
Miles per hour
Words per second
Heartbeats per minute
Feet per seconds

34. Speed= Distance/Time
The car is driving 53 miles every hour. Answer: 53 mph The car is driving 160 miles every 2 hours. Answer: The car has traveled 497 kilometers in 11 hours.
Reading Check #6

35. Temperature Temperature-how hot or cold an object is
The Kelvin (K) is the SI unit for measuring temperature
The Kelvin scale starts at 0 K, the coldest possible temperature
Reading Check #7

36. Drawings, Tables, and Graphs

37. Scientific Illustrations
What does a drawing show?
What does a photograph show?

38. What does a drawing show?
They can show details and things you cannot always see
Drawings can help solve problems
Reading Check #1

39. What does a photograph show?
Shows an object at one moment in time
A movie is made of a series of photographs
A movie shows how an object moves and can be slowed or sped up to show interesting things about objects

40. Tables and Graphs What is the difference between a table and a graph?
What does a line graph show?
What does a bar graph show?
What does a circle graph show?
How do you make a circle graph?
Why is the scale of a graph important?

41. What is the difference between a table and a graph?
Lists information in columns and rows
Columns are vertical (go up and down)
Rows are horizontal (go left to right)
Drawing that shows data
Shows relationships better than a table alone
Three most common types:
Line graphs
Bar graphs
Circle graphs

42. TABLES

43. GRAPHS

44. Endangered Animal Species in the United States
Year
Number of Endangered Species
1984
192
1986
213
1988
245
1990
263
1992
284
1994
321
1996
324
1998
357
2000
379
2002
389
Reading Check #2

45. Favorite MLB Baseball Team
Favorite Color
Favorite MLB Baseball Team
Number of Siblings
Favorite Sport
Favorite Pizza
How You Got to School

46. What does a line graph show?
Line graphs show changes in data over time
Variables-things that change
Like the number of endangered animals each year!
A line graph shows the relationship between two variables…both must be numbers.
Reading Check #3

47. Title
Dependent Variable
Independent Variable (Year)
Reading Check #4

48. REMEMBER! Independent Variables are purposely changed and controlled
Examples: Years, sessions, dates
Dependent Variables are changed because the Independent Variables are changed first
Examples: height of plants, number of animals, increase of students at Tremont

49. Choose ONE of the following activities!
Jumping Jacks
Sit-ups
Push-ups
Punches
Jumps in place or side to side

50. What do you think will happen?
Do as many of your chosen activity as you can in 20 seconds.
Count how many times you complete.
Write down the session (1-5) and how many you completed on a piece of paper.
Repeat 5 times!

51. What does a bar graph show?
Uses rectangular blocks or bars to show the relationships among variables.
ONE variable must be a number and ONE variable is a category (can be a number or group, like animals)

52. Title
Dependent Variable
Independent Variable (Animals)
Reading Check #5

53. Favorite MLB Baseball Team
Favorite Color
Favorite MLB Baseball Team
Number of Siblings
Favorite Sport
Favorite Pizza
How You Got to School

54. What does a circle graph show?
Shows the parts of a whole
Can be called a “Pie Graph”
The circle represents the whole pie and the slices are fractions of the whole pie.

55. How many slices are in a pizza? 8
Example: Who eats the Pizza at Mrs. Kemp’s
How many slices are in a pizza? 8
What Percentage of the total is 4 slices
50%
What percentage of the total is 2 slices
25%
What percentage of the total is 1 slice?
12.5%

56. Who eats the Pizza at Mrs. Kemp’s
Mrs. K eats 4 slices. What percentage of the total pie is that?
Lewis eats 2 slices what percentage of the total pies is that?
Josh eats one slice.
Emma eats one slice.

57. Who eats the Pizza at Mrs. Kemp’s
Emma12.5%
Josh 12.5%
Mrs. Kemp 50%
Lewis 25%

58. Tips for Circle Graphs? Organize your data into a table FIRST!
Figure about how many total sections of the “pie” there must be for your graph

59. Start at the center of the circle and draw your lines outward to the circumference
Try to label each piece of the wedge in the wedge first. Draw a line if it does not fit
Circle graphs need to have percentages!
Don’t forget to Title your graph!

60. CLASS EXAMPLE
Suppose you watched Big Bang Theory all day.
You saw 35 toy commercials, 25 cereal commercials, 25 fast food commercials, and 15 commercials for other products
What do you do first?

61. Step One: Put your Data in a Table Number of Commercials
Type of Product Number of Ads
Toys
Breakfast Food 25
Fast Food 25
Other products 15

62. Step Two: Calculate the total number of TV commercials in your study
= 100 Total Units
100 Total Commercials in all categories

63. Step Three: Calculate the percentage of each section to the total number of units
Toys 35/100
Breakfast Foods 25/100
Fast Foods 25/100
Other 15/100

64. Kinds of Ads in between Big Bang Theory
Toys 35/100
Breakfast Foods 25/100
Fast Foods 25/100
Other 15/100

65. Tremont Middle School Student Characteristics in 2014
White: 272
Black: 4
Hispanic: 7
Asian: 3
American Indian: 1
Pacific Islander: 0
Other: 10
Total: 297 Students

66. White: 91.6%
Black: 1.3%
Hispanic: 2.4%
Asian: 1%
American Indian: 0.3%
Pacific Islander: 0%
Other: 3.4%
Total: 297 Students