scientific method

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Scientific Method

K Warne

http://www.warnescience.net/




Investigation: Dissolving SaltHow much salt will dissolve in

water?

• Design and carry out a short investigation to answer this question.

• Carry out this investigation at home and write up your results.

• Bring this to your next lesson.





Objectives/OutcomesAt the end of this section you should be able to:-

• State and explain all the stages involved in scientific method.

• Pose a range of scientific questions based on simple everyday observations.

• Formulate hypothesis around given scientific questions.

• Identify variables involved in simple scientific investigations.

• Identify independent and dependant variables.

• Conduct a scientific investigation to find the answer to a stated scientific question.

• Evaluate a simple scientific investigation based on identification and control of variables.





Scientific Method

1. Observation

2. Question

3. Hypothesise

4. Investigation

5. Evaluation

>> Objectives

• The word Science comes from Latin word ‘scio’ which means to know.

• The the scientific process involves a step-by-step series of actions similar to walking we take one step at a time:





Making an observation• This means observing that something happens in a

certain way in the world around you.

• These observations can be about simple everyday happenings.

e.g. different plants flower at different times of the year, some powders dissolve in water and others don’t

Back

An example of something curious

–When the class was studying germination of seeds,

they grew seeds in cotton wool.

–One of them noticed that the seeds on one side of the

classroom germinated quicker than on the other side.





Asking a question• A question is asked to try to find out the reason for

the observation.

• What is the question for the germinating seeds?

Question: Did the seeds on one side of the

classroom germinate before the others because

they got more sunlight?

The question MUST contain the

TWO VARIABLES YOU WANT

TO INVESTIGATE.

Back

independant

dependant





Example QuestionsO: Salt dissolves in water.

Q: Does salt dissolve faster in warm water?

O: The sky is blue.

Q: Is the sky always the same colour blue?

Onions make my eyes water.

Do different onions affect eyes more?

Plastic is a major pollutant.

How quickly does plastic decompose?

Mercury poisoning is a world-wide problem.

Does mercury leak out of thermometers

Chewing gum is very difficult to get off a shoe!

.......





Formulating hypotheses

The hypothesis is a _____________ to the question you have just asked.

• The hypothesis is always written as a _________________ not a question.

• You can think of it as a ____________ of what you think will happen

• It must be able to be _____________ ____________, to see if it is true or not.





Formulating hypotheses eg.

• Think of possible hypotheses for the germinating seed question – must

a. If plants are given more sunlight then they will

germinate faster.

b. If plastic is made from organic material (INDEP.) then

it will decompose (rate)(dependant) faster.

c.Back





Investigation4. Designing an investigation to test the hypothesis

An experiment always contains the following steps

a. Aimb. Planning (Hypotheses,Apparatus,Method,Results)

c. Experimentd. Resultse. Interpreting/Analysisf. Conclusiong. Evaluation<<





Aim– the purpose of the experiment or what you want

to determine (find out)

Aim: A statement of intent relating to the answering of the

question. It must refer to both variables:

“To determine if there is a brand bubble gum that can be

removed easily from a shoe.”

Back





All the things about the experiment that can be changed.

Control variables: Things that must be kept CONSTANT to ensure a FAIR test.

• You must decide values for all your control variables. What seeds, temperature, how much water… YOU MUST INCLUDE ANYTHING THAT COULD POSSIBLY AFFECT THE INVESTIGATION (apart from the variables you are testing)

Independent variable: Variable that is CHANGED by YOU Does not depend on the other one.

• You must decide HOW and values for and by what amounts you will change your independent variable.

Dependant variable: Value DETERMINED by the independent variable. This is the one you will measure!

• You must try and estimate or predict what values your dependant variable will be.

Mini test experiments may need to be done at this point to help with some of these decisions.

Planning - Variables





Planning - Apparatus

– list of all the equipment (things) and chemicals you will need to do the experiment, and how much you will need of each. (Details must be included.)

Apparatus: eg Beaker (250 ml),

thermometer (0o -100o)

You may need to ask about what apparatus is

availible – or do your own research or experiments

to see what works!

Back





Planning - Method

• A step-by-step (NUMBERS step 1, 2 etc) plan of how to conduct the experiment

• 1)

• 2) etc.

• Must be carefully described so that anyone can repeat the experiment later and know exactly what to do.

• It must include details of exactly how you are going to collect results from the experiment.





Planning - Method

Make sure ALL control variables are taken care of.

i.E what values to use, how to control them etc.

You must give specific values and units – 25 cm3

etc. for all apparatus. Size of containers ...

You will have to make your own DECISIONS on a

number of these based on what is REASONABLE

and what fits with the APPARATUS available.

Do research or ask questions if you are not sure!

Back





(Planning) - Recording results

These are things you will ______________ in order to answer your question.

Results are best ________________. You must also show all the ____________ you have made regarding your control variables.

Control 1:____ Control 2: ______ etc





Interpreting Results/ Analysis• Graphs – try and find a suitable way of displaying

your findings in a graph.

Independent Variable Always on the X axis!

DependantVariable

Back

Independent Variable Dependant variableRun1 Run2 Run3 Av

Value 1

Value 2... You should try to have at

least 5 different values for your

independent.





Accuracy vs Consistency

X

X

X

XX

X

XX

X

1 2 3

Accurate …. Accurate …. Accurate …..

Consistent ….. Consistent ….. Consistent …..



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Evaluation

Here you look __________ at your experiment and decide if your results are ___________ and if there are any _____________ you could make if you did it again.

You should also list any _________________ for investigation that you have uncovered.





Scientific Method

1. Making an _________________.

2. Asking a ___________________.

3. Formulating a __________________

4. I_______________

a. A___b. P_________& A__________c. M________d. R_________e. I____________/A___________f. C_____________

5. E______________

>> Objectives





Hi -

This is a SAMPLE presentation only.

My FULL presentations, which contain loads more slides (with all the gaps filled in) as well as

other resources, are freely available on my resource sharing website:

www.warnescience.net

(paste into your browser if link above does not work)

Have a look and enjoy!

Keith Warne






scientific method

Education