Chapter one the nature of science
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Chapter One: The Nature of Science. 1.1 What is Science? 1.2 Science in Context 1.3 Studying Life. What are the GOALS of SCIENCE???. P rovide natural explanations for events in the natural world. U se those explanations to… understand patterns in nature

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Chapter One: The Nature of Science

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Chapter one the nature of science

Chapter One:The Nature of Science

1.1 What is Science?

1.2 Science in Context

1.3 Studying Life


What are the goals of science

What are the GOALS of SCIENCE???

  • Provide natural explanations for events in the natural world.

  • Use those explanations to…

    • understand patterns in nature

    • make useful predictions about natural events


What science is and is not

What SCIENCE is and is not…

  • Science is an organized way of gathering and analyzing evidence about the natural world

  • Not just a collection of never-changing facts or unchanging beliefs about the world.

  • Some scientific “facts” will change soon—if they haven’t changed already

    • scientific ideas are open to testing, discussion, and revision


Science change and uncertainty

Science, Change, and Uncertainty

  • Despite all of our scientific knowledge, much of nature remains a mystery. Almost every major scientific discovery raises more questions than it answers. This constant change shows that science continues to advance.

  • Learning about science means understanding what we know and what we don’t know. Science rarely “proves” anything in absolute terms. Scientists aim for the best understanding of the natural world that current methods can reveal.

  • Science has allowed us to build enough understanding to make useful predictions about the natural world.


Science as a way of knowing

Science as a Way of Knowing

  • Science deals only with the natural world

    • natural world - things that have not been substantially altered by human intervention.

  • Scientists collect and organize information in an orderly way, looking for patterns and connections among events.

  • Scientists propose explanations that are based on evidence, not belief. Then they test those explanations with more evidence.


Scientific method

Scientific Method

What do I already know?


What do you know about the process

What do you know about the Process?

  • Write down what YOU know on your paper by yourself.

  • With a partner share your information (side by side)

  • With a group of 4 share your information (square)

  • Share with the class using the whiteboards


Scientific methodology

Scientific Methodology:

  • A common misconception among students is that the “scientific method” is a set of five or six steps performed by all scientists, always in the same order.

  • There isn’t any single, cut-and-dried “scientific method.”

  • There is a general style of investigation that we can call scientific methodology.


Vocabulary

Vocabulary:

  • Inference

  • Data

  • Observation

  • Hypothesis

  • Theory

  • Science

  • Controlled Experiment

  • Control Group

  • Independent Variable

  • Dependent Variable


What procedures are at the core of scientific methodology

What procedures are at the core of scientific methodology?

  • Observing and asking questions

  • Making inferences and forming hypotheses

  • Conducting controlled experiments

  • Collecting and analyzing data

  • Drawing conclusions


Observations

Observations

  • Act of noticing and describing events or processes in a careful, orderly way.

  • Using your senses

    • What did you see, smell, hear, feel, taste?

  • Think something that nobody has though yet, while looking at something that everybody sees.” Arthur Schopenhaver philosopher

    • Leads to questions that no one has asked before


Asking questions and stating the problem

Asking Questions and Stating the Problem

  • What are you investigating?

  • Examples:

    • Does light affect the growth of plants?


Making inferences and forming hypotheses

Making Inferences and Forming Hypotheses:

Inference

Hypothesis

A scientific explanation for a set of observations that can be tested in ways that support or reject it.

A possible explanation for what you expect to happen

Ex. Plants will grow toward a source of light.

  • A logical interpretation based on what scientists already know.


In your notebook

In Your Notebook……

  • What is the difference between an observation and an inference?

  • List an example of each.


In your notebook1

In Your Notebook……

  • An observation is something noticed using the senses.

  • An inference is a logical interpretation of an observation.

Inference

Observation

  • Smell of gas in the hallway

  • Owl perched in tree

  • The owl has wings

  • A science class is doing a lab with Bunsen burners.

  • Owls live in trees

  • Owls can fly


Sample problems

Sample Problems:

  • Does ice melt faster in freshwater or salt water?

  • Does the amount of light received affect plant growth?

  • Does acid rain have an effect on frog egg development?


Sample hypotheses

Sample Hypotheses:

  • Ice melts faster in freshwater than in salt water.

  • Plant growth is greater when exposed to more sunlight.

  • Frog egg development is adversely affected by acid rain (slower growth and increased deformities).

  • Design an experiment to address one problem (question) Provide a short summary of the procedure. Identify the independent and dependent variable in your experiment.


Conducting controlled experiments

Conducting Controlled Experiments

  • Only one variable is tested at a time.

    • Variable = factors that can change

    • Ex. temperature, light, time, availability of nutrients

  • All other variables should be kept unchanged or controlled


The variable

The Variable

  • Variable – factors that change

  • Independent variable - variable that is deliberately changed (manipulated variable)

  • Dependent variable – the variable that is observed and changes in response to the independent variable (responding variable)


Control experimental groups

Control & Experimental Groups

  • An experiment is divided into control and experiments groups

  • The control & experimental group have the exact same setup except for the independent variable

  • Ex. The experimental group grows with light and the control group has no light


Identifying controls and variables

Identifying Controls and Variables


Example 1

Example #1

Smithers thinks that a special juice will increase the productivity of workers. He creates two groups of 50 workers each and assigns each group the same task (in this case, they're supposed to staple a set of papers). Group A is given the special juice to drink while they work. Group B is not given the special juice. After an hour, Smithers counts how many stacks of papers each group has made. Group A made 1,587 stacks, Group B made 2,113 stacks.


Example 2

Example #2

  • Homer notices that his shower is covered in a strange green slime. His friend Barney tells him that coconut juice will get rid of the green slime. Homer decides to check this this out by spraying half of the shower with coconut juice. He sprays the other half of the shower with water. After 3 days of "treatment" there is no change in the appearance of the green slime on either side of the shower.


Example 3

Example #3

  • Krustywas told that a certain itching powder was the newest best thing on the market, it even claims to cause 50% longer lasting itches. Interested in this product, he buys the itching powder and compares it to his usual product. One test subject (A) is sprinkled with the original itching powder, and another test subject (B) was sprinkled with the Experimental itching powder. Subject A reported having itches for 30 minutes. Subject B reported to have itches for 45 minutes.


Example 4

Example #4

  • Lisa is working on a science project. Her task is to answer the question: "Does Rogooti (which is a commercial hair product) affect the speed of hair growth". Her family is willing to volunteer for the experiment.


Collecting and analyzing data

Collecting and Analyzing Data:

Data – detailed records of experimental observations

  • Quantitative – numbers obtained from counting or measuring

  • Qualitative – descriptive and involve characteristics that cannot usually be counted

  • Charts & graphs are tools that help scientists organize their data

  • The larger sample size = more reliable data


Setting up a bar graph

Setting up a BAR Graph

  • Bar Graphs are used for comparison

  • This bar graph is comparing the overall (end result) height of the grass

Dependent Variable

Independent Variable


Setting up a line graph

Setting up a LINE Graph

Adding Nitrogen

Dependent Variable

Independent Variable


Drawing conclusions

Drawing Conclusions

  • Data is used as evidence to support, refute, or revise the hypothesis being tested

  • Should connect back to original hypothesis

  • Hypothesis can be reevaluated and revised

    • New predictions are made and new experiments designed

  • It is not always possible to test a hypothesis with an experiment (ex. animal behavior)

  • Ethics may prevent certain types of experiments, especially on human subjects

    • Experiments based on what humans were already exposed to


Redi s experiment on spontaneous generation

OBSERVATIONS: Flies land on meat that is left uncovered. Later, maggots appear on the meat.

HYPOTHESIS: Flies produce maggots.

PROCEDURE

Covered jars

Uncoveredjars

Controlled Variables:

jars, type of meat,

location, temperature,

time

Several

days pass

Manipulated Variables:

gauze covering that

keeps flies away from

meat

Responding Variable:

whether maggots

appear

Maggots appear

No maggots appear

CONCLUSION: Maggots form only when flies come in contact with meat. Spontaneous generation of maggots did not occur.

Redi’s Experiment on Spontaneous Generation


Communicating results reviewing and sharing ideas

Communicating Results, Reviewing and Sharing Ideas

  • Peer review allows ideas to be shared, and to test and evaluate each other’s work

  • Spontaneous Generation:

    • Redi Needham  Sapallanzani  Pasteur

    • Animation of Spontaneous Generation

  • Ensures accuracy

  • Sparks new questions and further studies


Theory

Theory

  • A well-tested explanation that unifies a broad range of observations and hypotheses

  • The meaning of the word theory in daily life is different from its meaning in science

    • A scientific theory is NOT a hunch

  • A useful theory that has been thoroughly tested and supported may become the dominant view among the majority of scientists

    • No theory is considered absolute truth

  • Theory versus a Law

    • Theory - represent something fundamental about how nature works

    • Law - can often be reduced to a mathematical statement; based on empirical data

  • Science is always changing as new evidence is uncovered

    • Theories can be revised or replaced by a more useful explanation


Formative assessment

Formative Assessment:

  • On the index card provided, write at least three sentence that uses the chapter vocabulary terms and clearly shows the relationship between the terms. Index cards will be collected as students exit the classroom.

    InferenceControlled Experiment

    DataControl Group

    ObservationIndependent Variable

    HypothesisDependent Variable

    Theory


Homework

Homework:

  • Read Sections 1.1 (pgs 4-9) and 1.2

    (pgs 10-15); 1.1 Assessment (pg 23)

    #1-5, 7, 9-12 (write Q & only Answer for Multiple Choice)


Characteristics of living things

Characteristics of Living Things

What must one possess to be considered living?


Based on a universal genetic code

Based on a Universal Genetic Code

  • Contain directions for inheritance carried by DNA

  • Copied and passed from parent to offspring


Made of cells

Made of Cells

  • Smallest unit considered alive

  • Organized

  • Can be unicellular(bacteria) or multicellular(plants, animals, fungi)

  • Can be prokaryotic or eukaryotic cell(s)


Vocabulary1

Vocabulary

  • Prokaryote- unicellular organism that lacks a nucleus (bacteria)

  • Eukaryote- unicellular or multicellular organism whose cells contain a nucleus (plant, animal, fungi)


Grow and develop

Grow and Develop

  • Pattern of growth and development over time

    • Growth = increase in amount of material in an organism

    • Development = series of changes an organism undergoes in reaching its final form


Respond to environment

Respond to Environment

  • Organisms constantly need to respond to changes in their surroundings

    • A stimulus is anything (signal) in an organism’s environment that causes a reaction/response


Ability to reproduce

Ability to Reproduce

  • Sexual reproduction - 2 cells unite to produce a unique offspring

  • Asexual reproduction – single parent produces an identical offspring


Maintain a stable internal environment

Maintain a Stable Internal Environment:

  • Homeostasis – process by which organisms keep their internal conditions stable

    • For Example:

      • Body Temperature

      • pH

      • Blood glucose levels

      • O2 levels


Obtain use material and energy

Obtain & Use Material and Energy

  • Take in materials and energy to grow, develop and reproduce

  • Metabolism –combination of chemical reactions that build up or break down materials while carrying on life processes


Vocabulary2

Vocabulary

  • Autotroph- organisms that manufacture their own food (plants)

  • Heterotroph- Organisms that cannot make their own food (humans)


As a group change over time

As a Group, Change Over Time

  • Organisms can adapt – that make them suitable to environment

  • Over generations, groups of organisms evolve, or change over time

    • Well-adapted individuals survive and reproduce.


Adaptation example

Adaptation Example


Adaptation of a sloth s chill pace

Adaptation of a Sloth’s chill pace…

  • Why do sloths go so very slow?

  • A clip by David Attenborough looks into the lives of sloths and reveals that their chill pace is actually an adaptation as a result of poor nutrition from their diet of leaves. Rather than eating more for more energy, the sloth simply does less.

Click on picture for short video clip on a sloths adaptation

BBC Earth – Saying Boo to a Sloth


The metric system

The Metric System

What do I already know?


Metric system base units

Metric System & BASE UNITS

  • Universal language of scientists

  • Also known as the International System of Units (SI Units)

  • Length– meter (m)

  • Mass– gram (g)

  • Volume– liter (L)


Prefixes

Prefixes

kilo

hecto

deka

BASE

deci

centi

milli

k

h

da

BASE

d

c

m

Metric Prefixes are used before a unit to make it smaller or larger


How to convert units

How to Convert Units

  • Kilo-k1000

  • Hecto-h100

  • Deka-da10

  • BASE ---------

  • Deci-d0.1

  • Centi-c0.01

  • Milli-m0.001

  • Power of 10

  • Multiply or divide by a multiple of 10

  • Move the decimal point


Chapter one the nature of science

Metric Conversions

  • Locate unit you are starting with.

  • Locate unit you want to end up with.

  • Move the decimal point over (in the same direction) as many places you moved over in the chart.


Examples

Examples:

12 hm= ____ dm

8 cm = ____ m

0.64 kg = ____ mg

100 daL= ____ kL

40 mm = ___ dm

32 cg = ____kg

0.06 dL= ____ hL

36 dam = ____ km

7 cm = ____ hm

15 m = ____ mm


Check your answers

Check Your Answers

12,000 dm

0.08 m

640,000 mg

1 kL

0.4 dm

0.00032 kg

0.00006 hL

0.36 km

0.0007 hm

15,000 mm


Microscopes

Microscopes

Compound Light Microscope

Electron Microscopes

(TEM and SEM)


Overview of microscopes

Overview of Microscopes

  • Magnification – increase of an object’s apparent size

    • Total magnification:mag. of eyepiece x mag. of objective lens

    • Ex: (10X) x (4X) = 40X

  • Resolution (resolving power)– the distance needed to distinguish 2 points as separate

  • Three types of microscopes: compound light, transmission electron, scanning electron


Resolving power

Resolving Power

The human eye is capable of distinguishing objects down to a fraction of a mm. With the use of light and electron microscopes it is possible to see down to an angstrom and study everything from different cells and bacteria to single molecules or even atoms.


Compound light microscope

Compound Light Microscope

  • Specimen is enlarged as light passes through set of glass lenses

  • Can be used to view living specimens

  • Resolving power is limited to the physical character of light – up to 200 nm

  • Magnification up to 2000x

    • beyond ~2000x the image becomes

      blurry


Transmission electron microscope

Transmission Electron Microscope

  • Cannot be used to view living specimens

  • Transmits a beam of electrons focused by a set of magnetic lenses through a specimen

  • Creates a flat image

  • Magnification – up to 200,000x

  • Resolution – up to 0.2nm


Scanning electron microscope

Scanning Electron Microscope:

  • Cannot be used to view living specimens

  • A narrow beam of electrons is pass over the surface of the specimen, which is coated with a thin layer of metal, producing a 3D image

  • Magnification up to 100,000X

  • Resolution – up to 10 nm


Microscope comparison

Microscope Comparison

http://www.sciencelearn.org.nz/Contexts/Exploring-with-Microscopes/Sci-Media/Interactives/Which-microscope


Sem image

SEM image

A head louse clasping a human hair. The image was taken using an SEM at 110x magnification. At low magnifications like this, SEM generates three-dimensional images that are in focus throughout the depth of the sample.

http://www.sciencelearn.org.nz/Contexts/Exploring-with-Microscopes


Tem image

TEM image

Transmission electron microscope image of a human leukocyte (also known as a white blood cell), showing the Golgi apparatus, which is a structure involved in protein transport in the cytoplasm of the cell.

http://www.sciencelearn.org.nz/Contexts/Exploring-with-Microscopes


Microscope images

Microscope Images

http://remf.dartmouth.edu/imagesindex.html


Metric review examples

Metric Review Examples

1. 1 km = ___ m

2. 0.45 L = ___mL

3. 5000 mg = ___ g

4. 130 m = ___ km

5. 2500 mL = ___ L

6. 0.017g = ___ mg


Check your answers1

Check Your Answers:

1. 1000 m

2. 450 mL

3. 5 g

4. 0.13 km

5. 2.5 L

6. 17 mg


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