data metric system (si) taking measurements organization presentation

DATADATA

Metric System (SI) Metric System (SI) Taking MeasurementsTaking Measurements

Organization Organization PresentationPresentation

• Your data are all the records you have gathered from an investigation.

• The types of data collected depend on the activity.

• Data may be a series of weights of volumes, a set of color changes, or a list of scientific names.

• No matter which types of data are collected, all data must be treated carefully to ensure accurate results.

DataData

• Sometimes the data seem to be wrong, but even then, they are important and should be recorded accurately.

• Remember that nature cannot be wrong, regardless of what you discover in the laboratory.

• Data that seem to be “wrong” are probably the result of the experimental error.

Metric SystemMetric System A decimal system of A decimal system of

measurement whose units are measurement whose units are based on certain physical based on certain physical standards and standards and scaled on scaled on multiples of ___ multiples of ___

Based on Based on units of 10units of 10

tenten

Kilo (k) = 1000Kilo (k) = 1000Hecta (h) = 100Hecta (h) = 100Deka (D) = 10Deka (D) = 10Base = 1Base = 1Deci (d) = 0.1Deci (d) = 0.1Centi (c) = 0.01Centi (c) = 0.01Milli (m) = 0.001Milli (m) = 0.001

Metric SystemMetric System

The system is easy to use because it is based on multiples of 10

1 meter = 100 cm1 kilogram = 1000 grams1 gram = 1000 milligrams1 liter = 1000 milliliters1 kilometer = 1000 meters1 centimeter = 10 millimeters

Measurement in ScienceMeasurement in Science

Scientists use a revised Scientists use a revised form of the metric form of the metric system called system called

Le Systeme International Le Systeme International d’Unitesd’Unites(International System (International System of Units) of Units) or SI Units or SI Units

S.I. Base UnitsS.I. Base UnitsThe International System of Units (S.I.) defines seven base units for the seven base quantities:

Quantity Name Symbol

length meter m

mass kilogram kg

time second s

electric current ampere A

thermodynamic temperature kelvin K

luminous intensity candela cd

amount of substance mole mol

S.I. Base UnitsS.I. Base Units

LengthLength

The distance from one point to The distance from one point to anotheranother

Meter – the SI unit of lengthMeter – the SI unit of length

Tool used to measure length Tool used to measure length depends on the size of the objectdepends on the size of the object

Larger objects (i.e. the room) Larger objects (i.e. the room) – – meter stickmeter stick

Smaller objects (i.e. pencil length) Smaller objects (i.e. pencil length) – – centimeter rulercentimeter ruler

Frequently used SI units

Length1 millimeter (mm) = 1000 micrometers (m)1 centimeter (cm) = 10 millimeters (mm)1 meter (m) = 100 centimeters (cm)1 kilometer (km) = 1000 meters (m)1 light-year = 9,460,000,000,000 kilometers (km)

Measuring LengthMeasuring Length

Measure the distance from Point A to BMeasure the distance from Point A to B

What distance is Point A? Point B?What distance is Point A? Point B?

What is the total distance between points?What is the total distance between points?

4.5 cm 6.4 cm

6.4 cm – 4.5 cm = 1.9 cm

MassMass The amount of matter in somethingThe amount of matter in something Mass is measured using a balance or triple Mass is measured using a balance or triple

beam balancebeam balance Or an electronic balanceOr an electronic balance

MassMass

The SI unit for mass The SI unit for mass is the kilogram (kg)is the kilogram (kg)

The gram is the base The gram is the base unitunit

However, some However, some measurements of mass measurements of mass like the mass of vitamins like the mass of vitamins or medicines are so small or medicines are so small that we use milligrams that we use milligrams (mg) to measure their (mg) to measure their massmass


Mass1 gram (g) = 1000 milligrams (mg)1 kilogram (kg) = 1000 grams (g)1 metric ton = 1000 kilograms (kg)

Measuring MassMeasuring MassMeasured using a balanceMeasured using a balance

What is the mass of this object?What is the mass of this object? 175 g

AreaAreaAreaArea is a physical quantity expressing the is a physical quantity expressing the

size of a part of a surface. size of a part of a surface. The term can also be used in a non-The term can also be used in a non-

mathematical context to be mean mathematical context to be mean "vicinity"."vicinity".

Surface areaSurface area is the summation of the is the summation of the areas of the exposed sides of an object.areas of the exposed sides of an object.


Area 1 square meter (m2) = 10,000 square centimeters (cm2)1 square kilometer (km2) = 1,000,000 square meters (m2)

Measuring AreaMeasuring Area

Area = Length x WidthArea = Length x Width

2 cm

2 cm

1 cm

1 cm The square has an area of 4 squarecentimeters (4 cm2)

Area = l x l2

= 2 cm x 2 cm

Area = 4 square centimeters (4 cm2)

Measuring AreaMeasuring Area

Calculate the area of the following rectanglesCalculate the area of the following rectangles

5 cm

Area =

Area =

cm

8 cm

Area =

Area =

3 cm X 8 cm2 cm X 5 cm

24 cm210 cm2

2 cm 3 cm

VolumeVolume

The amount of space a The amount of space a substance takes upsubstance takes up

Volume of a liquid is found Volume of a liquid is found using a graduated cylinderusing a graduated cylinder Unit is liters (L) or milliliters Unit is liters (L) or milliliters

(mL)(mL)


Volume1 milliliter (mL) = 1 cubic centimeter (cc) or (cm3)1 liter (L) = 1000 milliliters (mL) or 1 dm3

Measuring VolumeMeasuring Volume

Liquid volume measured using graduated Liquid volume measured using graduated cylindercylinder

Read volume at Read volume at meniscusmeniscus ( downward ( downward curve of water)curve of water)

What is the volume of What is the volume of this liquid?this liquid?

45 mL45 mL

Measuring VolumeMeasuring VolumeFind the volume of these liquidsFind the volume of these liquids

16 mL15 mL 12.5 mL

VolumeVolume

Volume of a solid is found using the Volume of a solid is found using the volume equation volume equation length x width x heightlength x width x height In this equation, we are also multiplying the In this equation, we are also multiplying the

units together so units for the units together so units for the volume of a solid are…volume of a solid are…

m x m x m = mm x m x m = m33 ORORcm x cm x cm = cmcm x cm x cm = cm33

Also know that 1 mL = 1 cmAlso know that 1 mL = 1 cm33 = 1 cc (cubic = 1 cc (cubic centimeter)centimeter)


Solid volume measured using volume Solid volume measured using volume equation (l x w x h)equation (l x w x h)

What is the volume of a cube that is 2 cm x 2 cm x 2 cm?

Volume = l1 x l2 x l3

= 2 cm x 2 cm x 2 cm

Volume = 8 cubic centimeters (8 cm3)


Calculate the volume of the boxCalculate the volume of the box

5 mm2 mm

6 mm

Volume =

Volume =

Volume = 60 mm3

6 mm X 5 mm X 2 mm

l x w x h

Water DisplacementWater Displacement

Some solid samples, such as an Some solid samples, such as an irregularly shaped rock cannot have their irregularly shaped rock cannot have their volume measured easily by using the volume measured easily by using the volume equation (length x width x height)volume equation (length x width x height)

For these solids, scientists use a For these solids, scientists use a technique called technique called Water Displacement Water Displacement


Steps of Water DisplacementSteps of Water Displacement1. Add water to a graduated

cylinder and record its volume (ex: 7 ml)

2. Place the irregularly shaped solid into the graduated cylinder already containing water and record the new volume (ex: 9 ml)


3. Subtract the smaller volume(combined volume) from the larger volume (water only) to get the volume of the irregularlyshaped solid. (ex: 9 ml – 7 ml = 2 ml)

4. We would say that the irregularly shaped solid takes up 2 ml of space. Since it is a solid, we need to state the volume using cm3 so we would say that its volume is 2 cm3

Volume = VVolume = V2 2 – V– V11

Volume = 30Volume = 30 – 20– 20

Volume = 10 mLVolume = 10 mL


= 10 cm= 10 cm33

TemperatureTemperature

The amount of heat in The amount of heat in somethingsomething

• Tool used to measure Tool used to measure temperature is a temperature is a thermometerthermometer

Celsius is the unit of Celsius is the unit of measure in the metric measure in the metric systemsystem

TemperatureTemperature

SI unit for SI unit for temperature is the temperature is the Kelvin (K)Kelvin (K) Notice that there is no Notice that there is no

degree sign used!degree sign used! Kelvin scale is easier Kelvin scale is easier

for scientists to usefor scientists to use To calculate Kelvin To calculate Kelvin

you add 273 to the you add 273 to the Celsius temperatureCelsius temperature

Ex. 23 Ex. 23 ○○C = 23 + 273 = C = 23 + 273 = 296 K296 K

Reading a ThermometerReading a ThermometerWhat’s the temperature?What’s the temperature?

-14 ○C 24.5 ○C

-5

-10

-15

-5

-10

-15

-5

-10

-15

30

25

20

-5

-10

-15

-14.0 ○C

TimeTime

The period between 2 eventsThe period between 2 events The SI unit of time is the second (s)The SI unit of time is the second (s) Measurement tool of time is a stopwatchMeasurement tool of time is a stopwatch

Recording and Organizing Recording and Organizing Laboratory DataLaboratory Data

•There are many ways to record and organize data, including:•data tables, charts, and graphs.

•It is important to include the appropriate units when you record data.

•Remember that DATA are measurements or observations, not merely numbers.

•Data tables, graphs, and diagrams should have descriptive titles to ensure that another person can understand them without having been present during the investigation.

Many important scientific discoveries have been made accidentally in thecourse of an often unrelated laboratory activity. Scientists who keep verycareful and complete records sometimes notice unexpected trends in andrelationships among data long after the work is completed. The laboratory notebooks of working scientists are studded with diagrams and notes; every step of every procedure is carefully recorded.

Data Tables and ChartsData Tables and Charts

For example, if you collected data on plant growth that included boththe length of time it took for the plant to grow and the amount of growth,you could record your data in a table (as shown below).

Data tables are probably the most common means of recording data.Although prepared data tables are often provided in lab manuals, it isimportant that you be able to construct your own. The best way to dothis is to choose a title for your data table and them make a list of thetypes of data to be collected. This list will become the headings foryour data columns.

Time in DaysTime in Days Height of Plant (cm)Height of Plant (cm)

1 10

3 12

5 15

7 18

9 20

Plant Growth Data Example Data Table

These data are the basis for all yourlater interpretations and analyses. You canalways ask new questions about the data,but you cannot get new data without re-peating the experiment.

Ways to Record DataWays to Record Data

Data TablesData Tables::

Must have a Must have a titletitle

Must include Must include relevant datarelevant data

Must have labeled Must have labeled columnscolumns

Number of FliesNumber of Flies on Meat per Day on Meat per Day

DayDay Number Number of Fliesof Flies

11 1010

22 5050

33 160160

44 4040

55 00

66 00

GraphsGraphs

Pie (circle) graphsPie (circle) graphs Line graphsLine graphs Bar graphsBar graphs

After data are collected, you must After data are collected, you must determine how to display themdetermine how to display them

One way of showing your resultsOne way of showing your resultsis to use a graphis to use a graph

Three types of graphs are commonly usedThree types of graphs are commonly used

Pie Graph: Pie Graph: Used to show how a part relates to the wholeUsed to show how a part relates to the whole

Needed to show percentages effectivelyNeeded to show percentages effectively

Ways to Graph DataWays to Graph Data

NCHS’s Biology Ice Cream Survey

Vanilla 21.0%Chocolate 33.%Strawberry 12.0%Raspberry 4.0%Peach 7.0%Neopolitan 17.0%Other 6.0%

Ways to Graph DataWays to Graph Data

(Continued)(Continued)

Line graphLine graph: used to : used to show change over show change over timetime

Bar graphBar graph: used to : used to compare quantitiescompare quantitiesin different categoriesin different categories

Be sure to include:Be sure to include: TitleTitle Axis labelsAxis labels KeyKey

Making a Line Graph Making a Line Graph Start with your data table Draw and Label Axes

Independent Variable on the x-axis

Dependent Variable on the y-axis

Would help to know that this experiment

was done with paper towels

Experimental Data

IndependentIndependent

VariableVariable

Submersion time

(seconds)

DependentDependent

VariableVariable

Average height

liquid rose (mm)

1010

1515

2020

2525

3030

3535

4040

1111

1414

1414

1515

1616

1717

1919

Ave

rag

e h

eig

ht

liq

uid

ro

se (

mm

)Submersion time (sec)

Making a Line GraphMaking a Line Graph(Continued)(Continued)

Using your data table, write data pairs

(10, 11)(15, 14)(20, 14)(25, 25)(30, 16)(35, 17)(40, 19)

Experimental Data

IndependentIndependent

VariableVariable

Submersion time

(seconds)

DependentDependent

VariableVariable

Average height

liquid rose (mm)

1010

1515

2020

2525

3030

3535

4040

1111

1414

1414

1515

1616

1717

1919


Use your data pairs to determine the scales for the axes

2. Write Data Pairs

(10, 11)(15, 14)(20, 14)(25, 25)(30, 16)(35, 17)(40, 19)

Start plotting your data pairs



After plotting data, draw a line “of best fit”


Complete the graph by summarizing its findings

“As the length of time the paper towelwas submerged increased, the heightthe liquid rose also increased.”

Making a Bar GraphMaking a Bar GraphAgain, Start with your data table Draw and Label Axes

Using your data table, write data pairs

Making a Bar GraphMaking a Bar Graph(Continued) (Continued)

Use your data pairs to determine the scales for the axes



Start plotting your data pairs

After plotting data, fill in bars


Include a key if needed

36

32

28

24

20

16

A B C D E F

Brand of paper towel

Wat

er a

bso

rbed

(m

L)

Complete the graph by summarizing its findings


•Brands A and D were the most effective water absorbers.

•The least effective absorber was Brand B.

•Brands C, E, and F absorbed intermediate amounts of water.

5. Summarize Trends

36

32

28

24

20

16

A B C D E F

Brand of paper towel

Wat

er a

bso

rbed

(m

L)

Graphing ReviewGraphing Review Purposes:Purposes:

Organize and analyze dataOrganize and analyze data Show patternsShow patterns Communicate informationCommunicate information Allow scientists to make predictionsAllow scientists to make predictions

Components:Components: Appropriate titleAppropriate title Equal units on each axis with good use of spacingEqual units on each axis with good use of spacing Labels on each axis including units Labels on each axis including units

(example, mm, sec., kg.)(example, mm, sec., kg.) Neatly created using a variety of colorNeatly created using a variety of color

Types of GraphsTypes of GraphsGraph Review

Statistical Methods Statistical Methods & &

Analysis of ErrorsAnalysis of Errors

ERRORERROR

May be defined as a deviation from the May be defined as a deviation from the absolute value or from the true average absolute value or from the true average of a large number of results.of a large number of results.

TYPES OF ERRORSTYPES OF ERRORS

1.1. Determinate error - constantDeterminate error - constant

2.2. Indeterminate error – Indeterminate error – random or accidentalrandom or accidental

Determinate ErrorDeterminate Error Usually present in each measurement and affect Usually present in each measurement and affect

all observations in a series.all observations in a series. Example:Example:

Errors in calibrationErrors in calibration Operation in measuringOperation in measuring Impurities in the reagents or drugsImpurities in the reagents or drugs Biased personal errorsBiased personal errors Pouring or mixingPouring or mixing Weighing operationsWeighing operations Matching colorsMatching colors Making calculationsMaking calculations

Indeterminate ErrorIndeterminate Error

Occur by chanceOccur by chanceVary from one measurement to the nextVary from one measurement to the nextYield a random pattern around an averageYield a random pattern around an averageOccur also in the filling of capsulesOccur also in the filling of capsulesRandom fluctuations in temperature and Random fluctuations in temperature and

other factorsother factors

PRECISION & ACCURACYPRECISION & ACCURACY

ACCURACY – is the degree of closeness of ACCURACY – is the degree of closeness of

a measured or calculated a measured or calculated

quantity to its actual (true) quantity to its actual (true)

value.value.

PRECISION – also called PRECISION – also called REPRODUCIBILITYREPRODUCIBILITY

the degree to which the degree to which

measurements or calculations measurements or calculations

show the same similar results.show the same similar results.

Comparing Comparing ACCURACY & PRECISIONACCURACY & PRECISION

HIGH Accuracy, LOW precision LOW Accuracy, HIGH precision

Prepare for an exam next meeting …

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data metric system (si) taking measurements organization presentation

Documents

datametric system si

types of data

base unitslengththe

cm1 kilogram

base quantities

base unithowever

centimeters cm1 kilometer

si unit of lengthtool