BMCU 1022

EXPERIMENTAL METHOD

CHAPTER 1Introduction to Experimental

Method

Importance of experiment in science and engineering

Problem in engineering can be divided into 2 approaches:

1. Theoretical method

2. Experimental methodWorks on explaining or

forecasting the result of an experiment based on analytical model and physical concept regarding on some phenomenon.

The theory suggested will be tested, measurement of quantity, deciding conclusion and will be used for building a good exercise in conducting an experiment.

• Basic concept

• Main principle

• Analysis method

• Measurement system

• Apparatus system

• Hardware/ software

Knowledge needed: Knowledge needed:

List down the criteria for each theoretical method and experimental method.

CLASSIFICATION OF EXPERIMENT

Theoretical method Experimental method

Mathematical model analysis on real world, where assumption is needed

Analysis on real situation; assumption is not needed

Give general results for all type of problems

Give specific results

Relaxation in assumption lead to complexity of mathematical model

Measurement devices with high accuracy are needed, if use apparatus is more complex

Not need to have many accommodations (trained person, pen, pencil )

Complete and expensive laboratory accommodation is needed

Research can be started immediately

Time delay is needed for equipment’s preparing and testing

Criteria of theoretical method and experimental method

Experimental methodExperimental method involves manipulating one variable to determine if changes in one variables cause changes in another variable.

Objective: to determine the optimum strength of composite materials with different nanoclay loading amount.

Example

Variables:

1. Composite materials’ strength, Mpa

2. Nanaclay amount, wt% Varied, 1wt%, 2wt%, etc

Change/affected/result

This method relies on controlled methods, random assignment and the manipulation of variables to test a hypothesis.

Generally, the experiment will be conducted based on scientific method, which is basically been used for all type of experiment.

Scientific method1. Change only one variable at

one time,2. To test the method of

experiment3. To test the reproducibility

Experiment

Scientist

Engineer

To design an experiment that be used to prove the theory

To find the differences between result that been gathered from theory and experimental results

Generalized experimental methodObjective and preliminary planning of an exp.

Detail planning

Continuing on planning the methodology

Select instrumentation

Collect a few data & conduct a preliminary analysis

Collect the bulk exp. data & analyze the results

Organize, discuss and publish the findings

Modify the exp. Apparatus and/or procedure

Storing an experimental record“Main attention for experiment must be given to record each procedure in steps..”

Why we should record?

• next analysis can be implemented without many problems

• May be required to change a procedure, improvement of procedure or change in setting of equipment, etc.

• Reproducibility of an experiment

•…

“Main attention for experiment must be given to record each procedure in steps..”

Storing an experimental record

How to record?

• electronic devices – computer(Ms Words, etc.)• logbook/ laboratory journal

• Tools for arrangement and references when writing a report

• Main record in patent law

• Preparing the record for overall experiment

• Information storage regarding on the procedure that is difficult to find from journal articles

• As a note that explain the success or failure of an experiment

Logbook

Logbook has their role as:

Logbook

Must be binding; piece of paper are not allowed

All the pages must be numbered

• Design concept• first drawing or sketch• first explanation (writing)• first test or design• information regarding on first announcement to outside world

(Generally), must be included

Logbook for engineering studentFor engineering students, usually the experiments that been conducted are for:

• to understand a concept in textbook

• to implement a standard test; e.g. hardness test, tensile test

• to check performance of a machine

• to find physical coefficient; e.g. gravitational acceleration, elastic modulus for a metal, etc.

1.Use a bound notebook for your log2.Handwritten (exception: research is

primarily on the computer or use a handled PDA to records)

Recommended

Logbook for engineering student• Date of experiment

Date• Objective(s)

Objectives• Apparatus that been prepared; take note

regarding on how to use the apparatus, preparation, etc.

Apparatus• Create a table for the reading that been

taken, together with their UNITSTable/ Result• Record all information needed to decide an

overall experimental errorsAnalysis/

Data• Make a necessary decision in order to

evaluate an effectiveness and level of success for an exp. Plot a graph required together with their estimation error

Discussion• Give a comment regarding on the

experiment and discuss the result that been gathered through crotical thinking

Conclusion

• Experimental design can be concluded as: – Objective – Planning – Evaluation – Uncertainty analysis – Cost – Calibration – Data gathered – Data reduction

Conclusion1. Problem in engineering can be divided into 2 approaches:

a) Theoretical methodb) Experimental method

1. Concept2. Knowledge

3. Criteria

2. Stages of experimental method3. Storing an experimental method 4. Logbook

5. Logbook for engineering students

Date

Objectives

Apparatus

ResultsAnalysis/ Data

Discussion

Conclusion