the pressure law using alba interfacing d burrett physics department hermitage academy argyll &...
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The Pressure Law Using ALBA Interfacing
D BurrettPhysics DepartmentHermitage Academy
Argyll & Bute
Apparatus
• ALBA temperature sensor
• ALBA pressure sensor
• ALBA interface• Round bottomed flask
(fully immersed, with hose to pressure sensor)
• Kettle
Setting Up ALBA Interface
• Connect power lead to mains supply
• Connect communication lead to PC
• Connect ALBA temperature sensor (analogue ch3)
• Connect ALBA pressure sensor(analogue ch4)
Setting Up ALBA Investigator 1
• Start ALBA software• Select ‘Run the
Investigator’ from Startup menu
• In General Settings select –– 10 s logging interval– Both Graph & Table
Setting Up ALBA Investigator 2
Setting Up ALBA Investigator 3
• In ‘Channels’ Settings ensure –– Temperature sensor is
detected on Analogue input 3
– Pressure sensor is detected on Analogue input 4
No other settings need to be changed, click ‘OK’ to continue.
Setting Up ALBA Investigator 4Graphs and table should appear in back ground behind ‘Setup Table Headings’ Box.
•Change Channel 3 to ‘Temperature’, symbol ‘T’
•Change Channel 4 to ‘Pressure’, symbol ‘p’
Click ‘OK’, then ‘Go’ to begin experiment.
Collecting DataAllow experiment to run until water in kettle boils.
Data Analysis 1
• Close both graphs• Click ‘Time’ column in
results table• Select ‘Table’ menu, then
‘Remove Column(s)’ and confirm
• Click ‘Use Data Points’ column
• Select ‘Table’ menu, then ‘Add Column(s)’ choose ‘1’ new column
Data Analysis 2
• Double click on table heading, change column properties
• Click on ‘Table Column Calculator; button
Data Analysis 3
• Type formula into calculator and confirm
• Click ‘Temperature’ and ‘Tot Pressure’ table headings
• Click ‘Quick Graph’ button
• Expand graph
Data Analysis 4• Double click on
entries in ‘Use Data Points’ column to de-select data and remove ‘plateau’ from graph
• Select ‘Graph’ menu, ‘Tools’ then ‘Best-fit line’
Data Analysis 5
• Select ‘Graph’ menu, ‘Edit graph’
• De-select ‘Auto-scale’
• Set x-axis from -320 to 100, y-axis from 0 to 120
• Click ‘Apply’
Data Analysis 6
• To find intercept on x-axis, place mouse pointer over graph
• Value of intercept appears at top left corner of graph
Evaluation 1
• True value of absolute zero is -273°C• Experimental value is too low because –
– Temperature measured by ALBA is not temperature of gas in flask – it is water temperature
– Pressure sensor is subject to a systematic error, under-reading by a small amount.
Evaluation 2
• Possible improvements– Place temperature sensor inside flask– Quantify systematic under-reading of
pressure sensor and adjust pressure readings accordingly in data analysis
– Encourage ALBA developers to produce a stand alone ALBA application for the pressure law
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