The Scientific Method Introduction to the Scientific Method

Scientific research seeks to correctly describe and explain what can be observed directly by human senses by technological extension (eg using chemical tests, scientific instruments etc) A systematic approach that helps the planning, conduct, description and explanation of observations in a way people can understand Scientific Method is a conventional way of undertaking this activity and provides:  A means of convincing others that observations and explanations are real and true  A toolbox of useful methods and techniques that can be applied to a variety of situations  A fair and open process of review and revision of knowledge and understanding The Scientific Method Lecture 1: Introduction to the Scientific Method

1.Observation 2.Hypothesis 3.Prediction 4.Experiment (or evidence gathering) Observations may prompt or be the deliberate subject of investigation. They may be of an event, a response, presence or absence, an association or distribution etc that must be described Descriptions may be: Qualitative — e.g. a type of behaviour, the shape of something, gender, colour, presence/absence of a character Or Quantitative — involving measurement or counting – e.g. height, weight, amount, number Numbers are meaningless in themselves and must be related to some other quality, the UNITS of measurement Lecture 1: Introduction to the Scientific Method The Four Steps

By international agreement, scientific investigations use the SI (Systeme Internationale) or MKS units of measurement Derived Units describe many other properties of observations in terms of the basic units, e.g. Area:meter x meter, or m 2 Volume:meter x meter x meter, or m 3 Basic Units Physical QuantityName of UnitSymbol Lengthmeterm Masskilogramkg Timeseconds Electric currentampereA TemperatureKelvinºKºK Luminous intensitycandelacd SI Multipliers MultiplierPrefixSymbol 10 9 gigaG 10 6 megaM 10 3 kilok 10 2 hectoh 10dekada decid centic millim microμ (mu) nanon picop Conventionally, indices are used to denote the multiplier Lecture 1: Introduction to the Scientific Method Measurement

To be valid, all observations must be repeatable (replicable) by other observers Quantitative measurements or numerical data (singular datum) are always preferred in scientific observations because:  they allow variation in the observations to be described  they permit statistical methods of data analysis to be applied that may help to understand the data, confirm its validity and convince others Lecture 1: Introduction to the Scientific Method Measurement

Start with a question — what, how, why, when, how often, how much? about the observation (s) and suggest a possible answer that can be investigated Lecture 1: Introduction to the Scientific Method Hypotheses & predictions Why don’t they get eaten? Why do they seem to occur in groups? How do birds behave towards them? What purpose do the colours serve? How could this phenotype have evolved? and so on … Suggest a hypothesis to explain why some caterpillars are brightly coloured and conspicuous while others are cryptic and blend into their surroundings Some caterpillar species are brightly coloured and appear to be conspicuous to predatory species such as insectivorous birds Suggest an experiment to test your hypothesis An example

For every hypothesis, there is a corresponding NULL HYPOTHESIS (H 0 ) against the predictions made in the hypothesis Scientific hypotheses are expressed in the null form of no difference, change, effect or trend because it is easier to apply statistical tests that can reject H 0 in favour of the alternative hypothesis supported by the predictions Experiment Tests the predictions made by the hypothesis and may lead to identification of a need or direction for further observation Data collection by means of: Laboratory experiments and tests Field experiments and surveys Carefully defined and specified observations must be carefully planned to ensure observations and measurements …….. Lecture 1: Introduction to the Scientific Method Null Hypotheses

record the right type of information – including factors which may affect the values of data or events being recorded (sources of error ) are accurate – the observed value agrees closely with the true value, not influenced by human errors e.g. misreading of instruments, mistaken recording, rounding errors instrument errors e.g. systematic errors in a scale reading introducing bias are precise — repeated observations agree with each other are recorded in an organised way that will not lead to confusion at a later time, e.g. failure to label data or state units of measurement are bias-free — not affected by recorder choice or presence but truly random observations that are representative of the bigger picture, e.g. whole population Standardisation of experimental method is crucially important!! Null Hypotheses Lecture 1: Introduction to the Scientific Method

Experiments are often designed in a way that fix or control variables that may affect the observations being made This usually involves keeping them constant, e.g. light level, temperature, volume of reactants, container size etc The dependent variable is the response that is being observed and recorded The independent variable is the influencing factor under investigation Variables Lecture 1: Introduction to the Scientific Method

The Publication of Research A structured scientific report must include the following components / sections: ► A TITLE ► An ABSTRACT ► An INTRODUCTION ► A MATERIALS & METHODS section ► A RESULTS section ► A DISCUSSION and interpretation of the results ► ACKNOWLEDGEMENTS All scientific reports must be written in the third person and in the past tense There's not much good in finding out things if no-one knows what you have discovered! Lecture 1: Introduction to the Scientific Method ► A► A BIBLIOGRAPHY