![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhpN6LmU70kCxQ6vrViCWVIDNX3H6v_2EuOfaL9GKuRtSOqjMwg45x6mquvnk_YY_AwmQdYBmY-gIcMuSyZl-539naZ2HbkNZF1GBiQe5Wt9MndJyQUqldvHTsYtDJU6fHPeDiabRXwfwHP/s200/800px-Steel_ruler_closeup.jpg)
A metre rule has sensitivity or accuracy accuracy of 1mm.
Precaution to be taken when using ruler
- Make sure that the object is in contact with the ruler.
- Avoid parallax error.
- Avoid zero error and end error.
Thermometer
There are 2 types of mercury thermometer
- Thermometers of range -10oC - 110oC with accuracy 1oC.
- Thermometers of range 0oC - 360oC with accuracy 2oC.
- Make sure that the temperature measured does not exceed the measuring range.
- When measuring temperature of liquid
- immerse the bulb fully in the liquid
- stir the liquid so that the temperature in the liquid is uniform
- do not stir the liquid vigorously to avoid breaking the thermometer
Stopwatch
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhapA953zb3GjJvNj1_pijKS2H9IxReXUPOMm0VBGyZQKB8HCrmrFq6uOrAkrqarTc0D1xsxSYqOze3iWdLd3ypT6IBo_evg4-q8cKsvLIxLddNfd-5V45MLzrqC8F-bjkK0WNbSMuNLJyT/s200/Stopwatch2.jpg)
There are 2 types of stopwatches
- analogue stopwatches of sensitivity 0.1s or 0.2s
- digital stopwatches of sensitivity 0.01s.