Instruments and Measuring

Calibrated instruments with suitable scales are used to measure quantities. There are various types of scales.

Scales

Linear and Non Linear Scales

A linear scale is a scale with equal divisions for equal vales, for example a ruler

Non Liner scales have adjacent graduations that not equivalent, for example in this picture of a non-linear power scale

Analogue and Digital Scales

Analogue scales use mechanical components such as springs or levers to determine weight and display their measurements with a moving dial or with graduated beams and sliding weights

Digital scales use an electronic load sensor such as a load cell to determine weight and convert this to a digital signal to be displayed on an LCD or LED.

(taken from http://wiki.answers.com/Q/What_is_the_difference_between_analogue_and_digital_scale

Instruments

There are many types of instruments that can be used in a lab to take measurements.

The choice of instrument depends on

• • type of quantity

  • size of quantity

The suitability of the instrument depends on the

• • range - The interval between the maximum and the minimum values of the quantity

  • sensitivity - An instrument's response to a unit change in input. The larger the response the more sensitive the instrument.

  • accuracy - This depends on the instruments calibration for correct absolute value

Here is a list of a few instruments used in the lab

Meter Rule

Stop clocks

Micrometer screw guage

Vernier Calipers [image & text]

Triple Beam Balance [Interactive]

Measuring cylinders

Voltmeters [image]

Ammeters [image]

Reading Scales

I've taken this video in the link below from another site

Reading Thermometers and rulers [Video]