lesson 2: designing and conducting investigations

30
2: Designing and Conducting Investig Ex – from, out Milli – 1/1000 Centi – 1/100 Deci – 1/10 Deka – 10 Hecto – 100 Kilo – 1000 Thermo – heat Micro – small An investigation is not considered “scientific” if it is not conducted following specific rules ensuring that the information gathered is accurate, unbiased, and ethical.

Upload: edison

Post on 05-Jan-2016

20 views

Category:

Documents


0 download

DESCRIPTION

Lesson 2: Designing and Conducting Investigations. Ex – from, out Milli – 1/1000 Centi – 1/100 Deci – 1/10 Deka – 10 Hecto – 100 Kilo – 1000 Thermo – heat Micro – small. - PowerPoint PPT Presentation

TRANSCRIPT

Page 1: Lesson 2:  Designing and Conducting Investigations

Lesson 2: Designing and Conducting Investigations

Ex – from, outMilli – 1/1000Centi – 1/100Deci – 1/10Deka – 10Hecto – 100Kilo – 1000Thermo – heatMicro – small

An investigation is not considered “scientific” if it is not conducted following specific rules ensuring that the information gathered is accurate, unbiased, and ethical.

Page 2: Lesson 2:  Designing and Conducting Investigations

Hypothesis = possible explanation or answer to a scientific question.

Variable = anything that can affect the results of an experiment.

Independent/manipulated = changed by youDependent/responding = what is measured

Variable Variables

Experimental Design = steps that must be taken to conduct a

test. EXAMINES ONLY ONE VARIABLE AT A TIME.

Page 3: Lesson 2:  Designing and Conducting Investigations

What You’re Measuring Base Unit Abbreviation

Length Meter m

Mass Gram g

Time Second s

Temperature Degrees Celcius oC

Amount of Substance Mole mol

Electric Current Ampere A

Fluid Volume Liter L

BASE UNITS

Page 4: Lesson 2:  Designing and Conducting Investigations

Milli Centi Deci BASE UNIT Deka Hecto Kilo

.001 .01 .1 1. 10. 100. 1000.

Millimeter(flea) centimeter decimeter METER dekameter hectometer

Kilometer(from RS

Middle to Main

Street)

Milliliter centiliter deciliter LITER dekaliter hectoliter kiloliter

milligram centigram decigram GRAM dekagram hectogram kilogram

Metric Units

Page 5: Lesson 2:  Designing and Conducting Investigations

Tools of the Trade

LENGTH or DISTANCE

Using the metric ruler to measure LENGTH:

Smiley Face4.7 cm OR47 mm

RULER

Page 6: Lesson 2:  Designing and Conducting Investigations

TEMPERATURE

Thermometer

Page 7: Lesson 2:  Designing and Conducting Investigations

VOLUME

Using graduated cylinders to measure VOLUME:

6.6 ml

meniscus

Graduated Cylinder

Page 8: Lesson 2:  Designing and Conducting Investigations

MASS 0 62.4

grams

62.4 grams0Why is the largest mass on the middle arm?

Triple Beam Balance

Page 9: Lesson 2:  Designing and Conducting Investigations

WEIGHT

TIMEVIEWING DISTANT OBJECTS

ORGANIZATION

Spring Scale Calculator/Computer

Telescope Stopwatch

Page 10: Lesson 2:  Designing and Conducting Investigations

VIEWING SMALL OBJECTS MicroscopeBe

able

to id

entif

y all t

he p

arts

of

the m

icros

cope

on

Text

pg 1

070.

Page 11: Lesson 2:  Designing and Conducting Investigations

QU

IZ T

OM

ORR

OW

!

Page 12: Lesson 2:  Designing and Conducting Investigations

Water levelbefore rock is added.

Water levelafter rock is added.

Difference in the volume before and after equals the volume of the rock.

Measuring the Volume of an Object

23 – 20 = 3 ml

20 ml

23 ml

Page 13: Lesson 2:  Designing and Conducting Investigations

Derived Units = units that are made up of two or more other units.

Density = m/v Speed = m/sForce (Newtons = m x kg/s2)Solid Volume = cm 3

Page 14: Lesson 2:  Designing and Conducting Investigations

DENSITY = MASS/VOLUME

REGULAR SHAPE IRREGULAR SHAPE

Class activity: Finding the density of two objects.

Page 15: Lesson 2:  Designing and Conducting Investigations

For each shape: Get the mass using a triple beam balance.

Regular Shape = 62.4 gramsIrregular Shape = 373.3 grams

Page 16: Lesson 2:  Designing and Conducting Investigations

For the REGULAR shape: Get the VOLUME using a METRIC RULER.

Metric (cm)

OLD (inches)

VOLUME =L x W x H

2 .5 cm 2 .5 cm

3.0

cm

VOLUME = 2.5 cm x 2.5 cm x 3.0 cm

VOLUME = 18.75 cm 3

Page 17: Lesson 2:  Designing and Conducting Investigations

Volume = After - Before

Volume = 15 ml

Volume = 90 - 75

75 ml90 ml

AfterBefore

For the IRREGULAR shape: Get the VOLUME using a GRADUATED CYLINDER.

Page 18: Lesson 2:  Designing and Conducting Investigations

To get the DENSITY: DENSITY = MASS/VOLUME

Regular Object Irregular Object

Mass = 62.4 grams

Vol = 18.75 cm3

D = 62.4 g / 18.75 cm3

D = 3.328 g/cm3

Mass = 373.3 grams

Vol = 15 ml

D = 373.3 g / 15 mlD = 24.9 g/ml

Page 19: Lesson 2:  Designing and Conducting Investigations

SCIENTIFIC METHOD

A series of organized steps that scientists use as a guide for solving a problem or answering a question.

Example Procedure:1. Label two beakers.2. Add 100 ml water to each.3. Measure and add 10 g salt

to one beaker.4. Stir to dissolve.5. Heat. Record the

temperature when the water in each beaker boils.

Variable is any factor that can affect the results.

Variables in this experiment:Beaker sizes, amount of water,

amount of salt, and heating method.

Misty wants to determine if water boils faster when salt is added. She believes water will boil faster if salt is added. Her hypothesis is “Salt water boils faster than unsalted water.”

Page 20: Lesson 2:  Designing and Conducting Investigations

Group A Group B Group C

Number of plants 2 2 3

Amount of light 35 watts 100 watts 35 watts

Size of pot 20 inches 20 inches 20inches

Amount of water Once daily Once daily Twice daily

Q. Suzanne wanted to test how light affects the growth of plants. She will measure the number of cm each plant grows.

1. Which two groups should Suzanne use for her experiment?A. Suzanne should use Group A and B.

2. What variable is Suzanne testing? A. She is testing the Amount of light.

http://www.sumanasinc.com/webcontent/animations/content/scientificmethod.html

Redi and Pasteur

Page 21: Lesson 2:  Designing and Conducting Investigations

Experimental Design

Control Group = group to which nothing is changed.

Experimental Group = group to which something is changed.

Example: Experiment in Coach book.

Control Group = beaker with only waterExperimental Group = beakers with salt addedVariable being Tested = salt

TEST ONLY

1 VARIABLE AT A TIME.

Page 22: Lesson 2:  Designing and Conducting Investigations

Solution Boiling PointTrial 1

Boiling PointTrail 2

Boiling Point Trial 3

1 L water 100 C 100 C 100 C

1 L water + 1 tbl salt

102.1 C 101.9 C 101.6 C

1 L water + 2 tbl salt

103.5 C 103.4 C 103.4 C

Independent variable =Dependent variable =

Control Group =Conclusion =

SaltBoiling Point1 L water groupSalt does increase the Boiling Point of water.

Page 23: Lesson 2:  Designing and Conducting Investigations

Solution Boiling PointTrial 1

Boiling PointTrail 2

Boiling Point Trial 3

1 L water 100 C 100 C 100 C

1 L water + 1 tbl salt

102.1 C 101.9 C 101.6 C

1 L water + 2 tbl salt

103.5 C 103.4 C 103.4 C

What prediction can you make based on these data? If 3 tbl salt are added to 1 L water, the boiling point will be higher than 103.4 C.

Page 24: Lesson 2:  Designing and Conducting Investigations

Scientists report their findings:• publish it in scientific magazines/journals• report it to other scientists• provide findings to the scientific community for scrutiny

• Chart/Table = summarizes data• Diagram/Model = explains or shows detail• Bar Graph = shows magnitude of data• Line Graph = relates two sets of data; shows how data changes• Circle Graph = relates parts of a whole• Flowchart = shows the order of steps• Scatter Plot = shows relationship between sets of data

Common Ways to Present Information:

Page 25: Lesson 2:  Designing and Conducting Investigations

Bias = a predisposition to a particular idea or conclusion.

Examples:1. A principal working to determine the most nutritious school menu would not get an unbiased response if he only asked 5 year olds.2. A congressman searching for information about the humane

treatment of animals would not gather accurate data if she only asked animal rights activists.

Scientists must guard against bias as they do their work. They must be careful that their sample is not biased and not to read their data with bias (seeing what they want to see instead of what is truly represented.

Page 26: Lesson 2:  Designing and Conducting Investigations

Sample = group of a population that is being studied.

POPULATION

TOO SMALL

GOOD SAMPLE SIZE

Page 27: Lesson 2:  Designing and Conducting Investigations

The importance of controls…

Per day10 ml H2O2 g fertilizer3 hrs sunlight

Per day15 ml H2O5 g fertilizer6 hrs sunlight

Per day20 ml H2O10 g fertilizer4 hrs sunlight

The scientist is studying the affects of fertilizer.

Is this a good experimental set up? NO

What is wrong with this experimental design?

How can we change this to make it correct?

10 10

3 30

Page 28: Lesson 2:  Designing and Conducting Investigations

DO IT NOW…

Read “Alternative Interpretations of the Data” on Coach pg 58.Answer the Discussion Question at the bottom.

When you finish, lay your pen/pencil down and sit quietly.

Page 29: Lesson 2:  Designing and Conducting Investigations

When a question involves a graph or other diagram, make sure you know what is being represented before you attempt to answer the questions.

Always read the LABELS describing the graph axes and lines.

TEST TIPS

Page 30: Lesson 2:  Designing and Conducting Investigations

Coach Book L2 QuestionsCoach Book L6 Discussion and

Review QuestionsTextbook pg 27 Analyzing Data

Complete the

Following: