Chapter 1 Scientific Investigation.ppt

Chapter 1Chapter 1

SCIENTIFIC INVESTIGATIONSCIENTIFIC INVESTIGATION

1.1 Method of Scientific Investigation

Science is all around us. Almost everything in our lives is closely related to science.

Science is from the Latin word, scientia, which means ‘to know’.

Scientists are curious about things and happenings in nature. They observe them and ask questions about them. Then they find answers to those questions.

One of the ways to obtain answers is to carry out a scientific investigation. In this way, scientists build up the knowledge of science (or scientific knowledge).

Steps Involved in A Scientific Investigation

1. Making Observation

a) When a scientist wants to investigate a phenomenon, the first step he or she would take is to observe the phenomenon carefully.

For example:

1. Making Observation

Two pieces of sarong, X and Y, of the same size and material are hung under the sun as shown in Figure 1.2 .After some time, it is observed that sarong X is dry but sarong Y is still damp.

b) An inference is made: The rate of drying cloth is influenced by the area it spreads out.

2. Identifying the problem

a) Based on the observation, a scientist will identify the problem for investigation (Figure 1.3).

b) The problem here refers to the question that can be solved experimentally.

3. Identifying the variables

a) Listing the factors (variables) that might influence an investigation is called identifying variables.

b) Before planning the investigation, one must determine which variable to manipulate and which responding variable to observe. The variables are summarised as follows:

3. Identifying the variables

Manipulated variable — the variable that is changed to see its effect.

Responding variable — the variable that changes in response to the manipulated variable.

Fixed variable — the variable that is kept constant or unchanged.

3. Identifying the variables

c) Based on the observation and the problem identified above, the three variables identified are shown in the following table.

4. Making a Hypothesis

a) A hypothesis is a simple statement of what one thinks will happen as a result of an experiment that one plans to do. It usually shows the relationship between the manipulated variable and the responding variable.

b) After identifying the variables in the above situation, a hypothesis that could be investigated is stated as follows:

Hypothesis: The larger the surface area exposed, the faster the rate of evaporation.

5. Planning the Investigation

a) An investigation or experiment is a scientific process used to examine the effect of changing one variable on another variable while keeping all the other variables constant.

b) A list of experimental procedures is determined. This includes:

5. Planning the Investigation

i) The apparatus and materials needed; In this case, needed are five Petri dishes of different diameters, measuring cylinder, stopwatch, ruler and alcohol.

ii) The procedures showing how to control the variables;The variables that are identified earlier sometimes cannot be measured easily. These variables can be defined in operational terms.

5. Planning the Investigation

For example:• The surface area of a liquid can be represented by the diameter of Petri dish.• The rate of evaporation is represented by the volume of liquid lost from the dish after 30 minutes.• The experiment is carried out with all the five different Petri dishes simultaneously so that the temperature and condition of the surrounding air can be kept constant.• the method of data collection, record and data analysis.

6. Carry out the Investigation

(a) An experiment is carried out to test the hypothesis by following the procedures that have been planned earlier.

(b) The manipulated variable and the responding variable are controlled according to the plan.

For example:

Each of the five Petri dishes of different sizes is filled with the same amount of alcohol. All the five Petri dishes with alcohol are exposed to the air under the same condition for 30 minutes.

7. Collecting Data

(a) Data is the outcome of controlling the variables. It refers to the observation made or measurements taken during the process of experiment.

(b) A data table is set up to organise all the collected data. The manipulated variable is usually placed in the first column of the table. The responding variable is placed in the second column or the third.

8. Analysing and Interpreting Data

a) Interpreting data involves organising the data so that you can work with the data and then analyse it to draw a valid conclusion.

b) Graphing is one of the primary ways of organising data for interpretation. Any activity that involves two quantitative variables can be organised in the graphical form.

c) By studying the graphs, you can see the relationship between the variables.

8. Analysing and Interpreting Data

For example:

By plotting the rate of evaporation of alcohol (responding variable) on the vertical axis and the surface area of liquid exposed to the air (manipulated variable) on the horizontal axis, the relationship between the two variables can be seen clearly.

9. Making a conclusion

Based on the analysis and interpretation of the graph, a conclusion can be made to check and confirm whether or not the hypothesis made earlier is accepted.

10. Writing a report

A complete experimental report should containthe following:(a) The aim of the experiment;(b) Hypothesis(c) The variables involved(d) Operational definition (if applicable)(e) Materials and apparatus(f) Diagram showing the set-up of the apparatus(g) Procedure(h) Observation I results(i) Analysis and interpretation of data(j) Conclusion

Please refer to page 4 in Science Textbook.

The importance of scientific investigation method1. Scientific investigation method is a method that is extremely effective in gaining, organising, and applying new knowledge.2. By using scientific investigation method, we can be more observant when conducting an experiment and more analytical when analysing the results.3. Sometimes personal and cultural beliefs may affect our perceptions and interpretations of certain things that happen around us.4. By using standard procedures in the scientific investigation method, some of the misconceptions and misinterpretations can be avoided or corrected. The scientific method can also help us to think critically and creatively.

Scientific Attitudes and Noble Values

1. Successful scientists always possess the right scientific attitudes and practise the related noble values in their field of work.

2. In school, students are required to adopt positive scientific attitudes and practise the related positive values in the learning of science.

3. The following are the attitudes and values which

are important to the learning of science in school:

• Interest and curiosity

Scientific Attitudes and Noble Values

• Honesty and accuracy• Diligence and perseverance• Realising science as a means to understand nature• Being systematic• Being critical and analytical• Kind-heartedness and caring attitude• Being objective• Being responsible and cooperative• Daring to try• Being fair and just• Being respectful and well-mannered• Being confident and independent

Scientific Attitudes and Noble Values

• thankful to God

• Appreciating the contribution of science and technology

• Clean and healthy living

• Appreciating the balance of nature

• Being flexible and open-minded

• Rational thinking