The World of Life ScienceChapter 1

Holt Science and Technology Life Science, 2001

Science Reading IntroductionMiss Elizabeth

MLK JHS 2006-2007

What is Science

1.Classifying – so when reading we will classify text by identifying the main idea and details

2.Experimenting – so when reading we will look for sequencing the order of ideas

3.Drawing Conclusion – so when reading we will draw conclusion as we read

4.Writing up experiment results so after reading we will write an expository essay. This is an essay that is meant to inform the reader. Some examples: – Tell what happened when . . .  – Write a report on . . .  – Explain how to . . .  – Describe how to  for . . .  .

Some links to reference: http://www.geocities.com/fifth_grade_tpes/expository.htmlhttp://library.thinkquest.org/10888/expos.html

5.Observing/inferring so when reading we will distinguish between cause and effect. Usually scientists observe the effect and infer its cause.

6.Determining cause and effect so also when reading we will determine cause and effect – the main cause and the main effect.

7.Comparing and contrasting so when reading we will look for things that are similar and that are different. Comparing and contrasting allow readers and scientists to group similarities and separate differences.

Education• Is a two way street – not just a one

way with teacher providing information. Education is two way with half from teacher providing information and half your response.

• Response is more than getting the right answer which requires memory but not deep thinking where a backhoe was used to build the second lane.

Science Notebook

• We will have “unit notebooks” to keep all our papers together, but also a journal where we can gather our thoughts and our questions. To help with developing our questioning or interrogation skills copy the following T-chart to the inside of your first science journal.

T-ChartQuestion and ResponseWhat is “on the page”

What is “between the lines”

•Direct information found in a portion of text you read – just the facts.•What is happening in the “story”; what are the parts of the “argument”?

•What words, phrases do you like? What clues do they give about the meaning or purpose or sense of the passage?•What questions do you have as you are reading? Where do these questions lead?•What words are unfamiliar? What do they mean? What do they add?•What main concepts begin to emerge for you?•How do the parts of the “story” or “argument” or “concept” fit together?

Wonderings – What is “off the page”•Wondering: what do I wonder abut now?•Memory: what does this remind me of?•Application: what areas of my everyday life incorporate these ideas?•Feeling: how do I feel about this “story”•Imagination: what story can you imagine and write about?

Structured Notes to help get the main ideas and important details together.

In the beginning of the class we will work through structured notes before reading is assigned. You will have directed reading worksheets to complete while reading. Once through those we will practice “deep reading” when we are really thinking about what we are reading.

Chapter 1: The World of Life Science

• What do you think – complete sentences mean complete thoughts

1. What tools do life scientist use?2. What methods do scientist use to

study life science?3. Can anyone become a life

scientist?

1.1 Asking About Life– Wondering – questions that just pop

into your mind. – Observing the world around us, being

curious. Leads to questioning our observations.

– Life Science is the study of living thing.

• It all starts with a question.– Easy to find in your backyard or

touring the world

• Looking for Answers– Science takes people with curiosity and

determination.•Who? Anyone can investigate the world

around us. Women and men from any cultural, ethnic, or income background can become life scientists.

•Where? Doing investigations in a laboratory is an important part of life science, but science can be studied in many other places too.

•What? Life Scientists or Biologists specialize in many different areas.

What Life Scientists Study

• how organisms function and behave, • how organisms interact with each

other and with their environment,• how organisms reproduce and pass

traits from one generation to the next,

• how organisms change over time and what are the origins of organisms

Why Ask Why?

• Two ways listed in your textbook 1. to combat disease and 2. to protect the environment.

• Can you think of some other reasons why study life science?

• Life science affects you and all the living things around you.

Combating Disease– Polio is a disease of the brain and informs

that causes paralysis. – We don’t see many people now but before

1960, it infected 1 in every 3,000 Americans. – It was life scientists who discovered way to

prevent the spread of the polio virus and we are now vaccinated.

– Children get 4 doses of IPV, at these ages:A dose at 2 months A dose at 6-18 monthsA dose at 4 months A booster dose at 4-6 years

Current diseases that scientists search for ways to fight

• Tuberculosis caused by Mycobacterium tuberculosis, a slow-growing bacteria that thrive in areas of the body that are rich in blood and oxygen, such as the lungs.

• AIDS caused by HIV (human immunodeficiency virus)

• Cystic Fibrosis caused by an inherited gene.

Protecting the Environment

• Why protect the environment?• What environmental problem can

you think of?• Pollution can harm our health and

the health of other animals and plants. When we cut down trees we alter and sometimes destroy the habitat of other creatures or the climate.

1.2 Thinking Like a Life Scientist• The Scientific Method

– Is a series of steps that is used to answer a question or solve a problem.

– The steps are applied creatively meaning sometimes scientists come back to a step, do the steps in a different order, or skip a step depending on the question

.

The steps:– Ask a question: based on observations– Form a hypothesis: a possible explanation

for what you have observed.– Test the hypothesis: by conducting

experiments.– Analyze the results: collected from

experiments.– Draw conclusions: from the results– Communicate results: to other scientist in

writing and in presentations

When researchers use the scientific method, can they repeat or switch the order of steps or do they need to keep them always exactly the same? Explain.

• Scientists can repeat or switch the order of steps as needed.

• The Scientific Method is a map and there is more than one way to reach your destination

Ask a question: based on observations

• Observations can take many forms:– Measurements of length, volume,

temperature, time or speed.– Descriptions of how loud or soft a sound is

or the color or shape of an organisms; what something does, how it moves, or its patterns of behavior.

– Scientist have to be careful when making observations that the observations are accurately made and recorded.

– Observations become data.

Form a hypothesis: a possible explanation for what you have observed

• When scientists form hypotheses they think logically, creatively, and keep in mind what they already know.

• A hypothesis must be testable by experiment or observation.

• A hypothesis that is not testable may not be wrong, but it is not USEFUL because it can’t be proved or disproved.

• Different scientists can have different hypotheses for the same question.

• Hypotheses are based on predictions.

Predictions• A prediction is a statement of cause

and effect that can be used to set up a test for a hypothesis.

• Predictions are usually stated in an “If ………, then…….” format.

• Once predictions are made, scientists can design experiments to see which predictions, if any prove to be true and support the hypothesis.

Self Check – Which of the following statements is a hypothesis?

1. Deformed frogs have been found in the United States and Canada.

2. Insecticides and fertilizers caused the frog deformities.

3. Frogs can easily absorb pollutants through their skin.

What do scientists use to answer a question or solve a problem?– the scientific method.– their imagination.– their creativity.

Test the hypothesis: by conducting experiments.

• Scientist try to design experiments that will clearly show whether a particular factor was the cause of an observed outcome.

• A factor is anything in an experiment that can influence the experiment’s outcome. Here we have lots of causes.

• Scientists control experiments so that only one factor at a time is tested.

• In a controlled experiment there is a control group and one or more experimental groups.– All the factors in the control group

and the experimental groups are the same except for one.•The one factor that differs is called the

variable.– Because the variable is the only

factor that differs between the control group and the experimental groups, •scientists have more certainty that

variable is causing the differences observed in the results.

• In order to be certain about the conclusions of an experiment, scientists should repeat the same experiment many times.

• Designing a good experiment requires a lot of thought and planning.

Self CheckHenry is testing the effects of different

antibacterial soaps on the growth of bacteria. His experiment contains several jars of the same strain of bacteria. Which of the jars described below is the control group?

1. To Jar A, Henry adds two drops of Super soap.

2. To Jar B, Henry adds two drops of Anti-B Suds.

3. To Jar C, Henry adds no soap.

Self Check• A scientist wants to study the possible

side effects of a new medicine, how should he/she set up this experiment? (How many groups, how much medicine, control group?) – how many groups? Depends on the kinds of

patients that will be treated by the drug.– how much medicine? Depends on

potencies that have been established by other tests.

– control group include a control group that receives no medicine

Analyze the results: collected from experiments.

• Ways to analyze results:– organizing your data into tables,

charts and graphs.– doing calculations to learn more

about your results.

Math BreakFinding the average of a group of

numbers is one way to analyze data.• Dr. Brown found that 3 seeds kept at

25°C sprouted in 8, 8, and 5 days. – To find the average number of days that it

took the seeds to sprout, she added 8,8, and 5 and divided their sum by, the number of subjects (seeds) in the group.

– She found the average number of days to sprout at 25°C was 7 days.

Math Break Self Check

• Dr. Brown also found that 3 seeds kept at 30°C sprouted in 6,5, and 4 days.

• What’s the average number of days that it took these seeds to sprout.

Draw conclusions: from the results

• When drawing conclusions, scientist have to decide whether the results of the experiment have shown that a prediction was correct or incorrect.

• When scientist find that a hypothesis is not supported by the tests:– they must try to find another explanation

for what they have observed.– they realize that they have eliminated one

possible factor.

What to do with a wrong hypothesis?

• If a tested hypothesis does not produce the expected results, – don't trash the results—it might lead

to another discovery.

• Proving that a hypothesis is wrong is just as helpful as supporting it. – Because either way, the scientist has

learned something.

Communicate results: to other scientist in writing and in presentations

• After concluding that your tests support your hypothesis, you should publish the results: – so that other scientists can learn

from you.– so that other scientists may repeat

the experiments to see if they get the same results.

Scientific Knowledge Changes

• Scientists continue to discover new information all the time.

• Each time a prediction is proven true, a hypothesis gains more support.

• A theory is a unifying explanation for a broad range of hypotheses and observations that have been supported by testing.

1.3 Tools of Life Scientists

• Tools for seeing• Computers• Systems of Measurement• Safety Rules

Tools for Seeing• Magnifying tools enables scientists to

observe smaller details:–Compound Light Microscope

•Compound because it has two lenses an ocular lens and an objective lens.

•Uses light to illuminate

–Electron microscope•Uses tiny particle called electrons to either

bounce off or penetrate a non-living sample. Very high magnification.

Chapter 1 Tools

• There are two types of microscopes that we will discuss:– Compound light microscopes - uses

light and two lenses– Electron microscopes - have better

resolution than compound light microscopes and uses an electron beam.

Microscopy Vocabulary

• Resolution – the ability to clearly distinguish the individual parts of an object

• Magnification – the enlargement of a structure by means of bending the light that passes through lenses in the case of a light microscope or a beam of electrons in case of an electron microscope

Lenses

• Convex lens: the ______ of the lens is thicker than the __________.

• Concave lens: the ______ of the lens is thicker than the __________.

middle

edgeedge

middle

Other Seeing Tools• X-rays, Magnetic resonance imaging

(MRI), and Computed Tomography (CT)– High energy photons pass through a sample

and an image is created.

Computers• First built in 1946 – sixty years ago

– Not commercially available until 1980’s.– Allow complex calculations and graphic

representation of data used to decide whether differences in experimental data are important.

Systems of Measurement

• The International System of Units, universally abbreviated SI (from the French Le Système International d'Unités), is the modern metric system of measurement.

• Developed by the French Academy of Sciences in the late 1700’s.

• A system of measurement based on the number 10.

Scientists use the International System of Units because it:– makes sharing results among

scientists easier.– contains units that are based on the

number 10.– standardizes a method of recording

observations.

Common SI Units

• Length – meter • Volume – cubic meter = m3

• Area – square meter = m2

• Mass – gram• Temperature – degrees Celsius =

°C

SI prefixes• King – kilo - 1000• Henry – hecto - 100• Died – deko - 10• Drinking – deci – 1/10 = 0.1• Chocolate – centi – 1/100 = 0.01• Milk – milli -1/1000 = 10-3 = 0.001Even smaller

Micro – 10-6 = 0.0000001Nano – 10-9 = 0.000000001

Safety Rules

• Safety First is the motto.• Having experiments in class

requires good behavior – and good attention.

• Always follow your teachers instruction

• Don’t take shortcuts