We use necessary cookies to make our site work. We'd also like to set optional analytics cookies to help us improve it. We won't set optional cookies unless you enable them. Using this tool will set a cookie on your device to remember your preferences. We do not use cookies for marketing purposes.
Necessary cookies enable core functionality such as security, network management, and accessibility. You may disable these by changing your browser settings, but this may affect how the website functions.
We utilise Google Analytics cookies to help us to improve our website by collecting information on how it's used. The cookies collect information in a way that does not directly identify anyone.
Answers to the most popular questions about NPL and our activities.
12 am,12 pm, midday and midnight meaning and the 24-hour clock.
Historically, there have been a variety of units of force and conversion factors.
There are no official definitions of the duration of spring, summer, autumn and winter.
All objects at temperatures above absolute zero emit thermal radiation.
We use these words on a daily basis, but do you really know the difference between mass, weight, force and load?
Density and specific gravity are both used to describe mass and can be used to compare substances.
Atmospheric pressure reduces with altitude for two reasons, both of which are related to gravity.
A platinum resistance thermometer (PRT) contains a piece of platinum wire, whose electrical resistance is proportional to temperature.
What can you do to ensure you receive the correct time?
The term g-force is used to convey values of force and acceleration.
The definition of a vacuum is not precise but is commonly taken to mean pressures below, and often considerably below, atmospheric pressure.
Want more detail? Delve into the subjects more deeply.
The SI units
Quantum
Graphene
NPLTime®
Our research and measurement solutions support innovation and product development. We work with companies to deliver business advantage and commercial success. Contact our Customer Services team on +44 20 8943 7070