Skill Chapter 3 Scientific Method St. Stephen’s College F.3 Biology Mr. Tso

Scientific Method 1.Introduction 2.Asking questions 3.Stating and testing hypotheses A.What is hypothesis? B.How to test a hypothesis? 4.Designing and doing experiment A.What is an experiment? B.Variables C.Controls D.How to draw conclusion from experimental results? E.Points to note in experimental design

IntroductionIntroduction The knowledge of biology can be discovered by the ________ _______. The scientific method involves several major steps: scientificmethod

Observation Problem Hypothesis Prediction Designing & performing experiment Results Conclusion

Observation Problem Hypothesis Prediction Designing & performing experiment Results Conclusion Grasshoppers are commonly found in grassland.

Observation Problem Hypothesis Prediction Designing & performing experiment Results Conclusion Why grasshoppers are normally found among grass?

Observation Problem Hypothesis Prediction Designing & performing experiment Results Conclusion Grasshoppers like to hide among green objects.

Observation Problem Hypothesis Prediction Designing & performing experiment Results Conclusion If identical conditions are provided, grasshoppers will gather around green objects most of the time.

Observation Problem Hypothesis Prediction Designing & performing experiment Results Conclusion Variables: Independent variable Dependent variable  colour of object  proportion of time a grasshopper stay on an object  proportion of time a grasshopper stay on an object

Observation Problem Hypothesis Prediction Designing & performing experiment Results Conclusion Statement of the aim: to determine the favoured colour for grasshoppers to stay on.

Observation Problem Hypothesis Prediction Designing & performing experiment Results Conclusion Aspects to consider in designing procedure: * position of objects * materials of the objects * smell of the objects * number of trials * others * position of objects * materials of the objects * smell of the objects * number of trials * others

Observation Problem Hypothesis Prediction Designing & performing experiment Results Conclusion Dealing with Data: * Table * Graph * Table * Graph

Observation Problem Hypothesis Prediction Designing & performing experiment Results Conclusion The most favoured colour for grasshoppers to stay on is green.

IntroductionIntroduction Observation and Recording Data Hypothesis Design Table Graph Conclusion Prediction Performing

Asking Questions Scientific inquiry begins with the observation and recording of phenomena. The next stage in the process involves ______ _________ about these observations in order to explain the phenomena. The questions posed define the ________ that the investigation takes. askingquestions direction

Activity Time Activity 1

Stating & Testing Hypothesis (What is hypothesis?) This is a _________ (not a question) that attempts to provide _______ to the questions based on the observations. statement answers

Stating & Testing Hypothesis (How to test a hypothesis?) The hypothesis should be testable by __________. A good hypothesis can be tested by experiment, the result of which support or contradict the accuracy of __________ based on the hypothesis. experiment predictions

Activity Time Activity 2 & 3

Designing and Doing Experiment (What is an experiment?) It is an operation carried out under _________ conditions in order to discover an ________ effect. controlled unknown

Designing and Doing Experiment (Variables) Conditions which can change in an experiment are called ________. There are _____ different types of variables in an experiment: variablesthree (1)___________ variable is the one which was deliberately changed Independent Dependent Fixed (2)_________ variable is the one which changed in response to the change of the independent variable. (3)_____ variables are all those conditions which do not change during the experiment.

Designing and Doing Experiment (Variables) It is vital that only ____ variable is manipulated each time. If more than one variable is manipulated, it is not possible to know which one is influencing the _________ variable. one dependent

Activity Time Activity 4

Designing and Doing Experiment (Controls) In order to draw valid conclusions from experimental results, the results of an experimental set-up have to be ________ with that of a ______ ______, which should be ________ to the experimental set-up in all respects except that the independent variables are not manipulated but kept ________. compared controlset-up identical constant normal treated A control may be defined as the set-up which is under _______ conditions. The ______ set-up is, therefore, the experimental set-up.

(3) It allows the ______ due to the fluctuations of environmental conditions to be corrected, as the fluctuations affect both the experimental set-up and the control set-up. (2) It forms a basis on which the effect of the factor under testing can be _________ or _________. Designing and Doing Experiment (Controls) The importance of the control: (1)It confirms that a particular result is due to the _____ _____ ______ but not others. factor under testing calculated estimated errors

Activity Time Activity 6, 7 & 8

(2) If the value of factor X ________, the value of activity Y will also _______ / will ________. OR Designing and Doing Experiment (How to draw conclusion from experimental results?) A prediction is often written in one of the following two ways: present increases increase decrease occur (1)If factor X is _______, activity Y will _____.

The following ____ theoretical cases illustrate how _____ conclusion may be drawn from experimental results: (Aim : to show that factor X is necessary for activity Y to be carried out.) Designing and Doing Experiment (How to draw conclusion from experimental results?) In reality, there should be _____ ____ one factor (X, A, B, C, D……. etc.) that could affect an activity (Y). That is to say factor X is only one of the many factors that could affect the activity Y. more four valid than

Aim:to show that factor X is necessary for activity Y to be carried out.) Designing and Doing Experiment (How to draw conclusion from experimental results?) Case (1) Set-up (I)Set-up (II) X, A, B, CA, B, C was carried out Factor X is necessary for activity Y to be carried out was not carried out Is there any difference in the initial conditions between the two set-ups? Is there any difference in their results?

Aim:to show that factor X is necessary for activity Y to be carried out.) Designing and Doing Experiment (How to draw conclusion from experimental results?) Case (2) Set-up (I)Set-up (II) X, A, B, CA, B, C was carried out Factor X is not necessary for activity Y to be carried out Is there any difference in the initial conditions between the two set-ups? Is there any difference in their results?

Aim:to show that factor X is necessary for activity Y to be carried out.) Designing and Doing Experiment (How to draw conclusion from experimental results?) Case (3) Set-up (I)Set-up (II) X, A, B, CA, B, C was not carried out No conclusion can be drawn Is there any difference in the initial conditions between the two set-ups? Is there any difference in their results?

Aim:to show that factor X is necessary for activity Y to be carried out.) Designing and Doing Experiment (How to draw conclusion from experimental results?) Case (4) Set-up (I)Set-up (II) X, A, B, CB, C No conclusion can be drawn because the two set-ups differ in more than one factor Is there any difference in the initial conditions between the two set-ups? No matter what the result is

Aim:to show that factor X is necessary for activity Y to be carried out.) Designing and Doing Experiment (How to draw conclusion from experimental results?) It can be seen that the ______ of case (4) is ____ because the experiment introduced _____ ____ one difference in the initial condition between set-ups. designbad morethan It can also be seen that conclusion may be drawn only if results of two or more set-ups are compared.

Activity Time Activity 5

(3) The potential problem due to _________ ________ is minimized by using a _____ sample size of organisms as far as possible. (2) The set-up must be well designed so that it is ________. Designing and Doing Experiment (Points to note in experimental design) (1) The variables must be _________ so that the hypothesis can be tested. controlled workable individual variationlarge

Activity on Scientific Method? ? ?

Activity 1:Asking Question (1)What was Fiona’s observation on the distribution of ants around different drops of sugary solution which she left on table carelessly? The number of ants gathered around different drops was different. (2)What question was asked by Fiona? Why are there different numbers of ants around different drops?

Activity on Scientific Method Activity 2:Stating Hypothesis What was Fiona’s hypothesis for her observation? Ants would choose sweet solutions.

Activity on Scientific Method Activity 3:Making Prediction Base on Fiona’s hypothesis, what prediction can be made? If the concentration of sugary solution increases, the number of ants gather around will increase. (Assumption:A more concentrated solution is sweeter.)

Activity on Scientific Method Activity 4:Identifying the Variables In Fiona’s experiment, (1)What was the independent variable? It was the sweetness of sugary solution. (2)What was the dependent variable? It was the number of ants gathered around each drop in one hour. (3)What were the fixed variables? Size of each drop, type of the sugary solution, etc.

Activity on Scientific Method Activity 5:Drawing Conclusion After the experiment, what conclusion could be drawn? Ants would choose sweeter solutions.

Activity on Scientific Method Activity 6: The following set-ups are used in an experiment to show the uptake of oxygen by a respiring animal: (1)The experimental set-up is tube ___. A (2)The control set-up is tube ___. B

Activity on Scientific Method Activity 7: The following set-up is used in an experiment to study whether light is necessary for photosynthesis: (1)The experimental set-up is region ___. A (2)The control set-up is region ___. B

Activity on Scientific Method Activity 8: The following diagram refers to an experiment for studying the conditions for seed germination: (1)The experimental set-up is beaker ___. B (2)The control set-up is beaker ___. A

Designing and Doing Experiment (How to draw conclusion from experimental results?) (I) (II)

Designing and Doing Experiment (How to draw conclusion from experimental results?) (I) (II) Case (1) After one hour ?

Designing and Doing Experiment (How to draw conclusion from experimental results?) (I) (II) Case (1) Can we draw a conclusion that grasshoppers like to stay on green objects?

Designing and Doing Experiment (How to draw conclusion from experimental results?) (I) (II) Case (2) After one hour ?

Designing and Doing Experiment (How to draw conclusion from experimental results?) (I) (II) Case (2) Can we draw a conclusion that grasshoppers like to stay on green objects?

Designing and Doing Experiment (How to draw conclusion from experimental results?) (I) (II) Case (3) After one hour ?

Designing and Doing Experiment (How to draw conclusion from experimental results?) (I) (II) Case (3) Can we draw a conclusion that grasshoppers like to stay on green objects?

Designing and Doing Experiment (How to draw conclusion from experimental results?) (I) (II) Case (4) After one hour ?

Designing and Doing Experiment (How to draw conclusion from experimental results?) (I) (II) Case (4) Can we draw a conclusion that grasshoppers like to stay on green objects?