A measuring tool is anything used to take a count of quantitative data, such as weight, length, time or temperature. Rulers and scales are two common types of measuring tools. Measuring tools can be very precise, but low quality ones can lead to faulty measurements.
Measuring tools are essential for many different types of jobs or exercises. For measuring length, rulers are the accepted choice. There are various types of rulers, including yardsticks and tape measures, that can measure different distances. Rulers are useful because they can have multiple measurement systems, such as metric and imperial units, are simple to use and have marks denoting subdivisions.
Scales are used for weighing things and can be very precise for chemistry, cooking or other scientific endeavours. There are hanging, pressure and balance scales which have different pros and cons and are useful for different needs, though pressure scales are the most common. Scales do need to be calibrated sometimes, and digital ones can wear out and provide a bad reading.
Temperature is measured with thermometers, and both digital and mechanical are used. Mercury used to be favored to measure temperature, but it has fallen out of favor due to its negative effects to exposed humans. Watches and clocks are used to measure time and can also be mechanical or digital.