What are the thermal effects on balances and weight? (FAQ - Mass & Density) : FAQs : Reference : National Physical Laboratory

Science + Technology
Science + Technology
NPL maintains a wide portfolio of internationally visible research programmes that advances measurement science, underpins the SI system and supports various cross-disciplinary technologies.
Acoustics
NPL undertakes long-term, leading-edge research to develop new and improved measurement methods that will impact on UK future services and products.
Advanced Materials
Materials technology is vital to industrial competitiveness and innovation across all sectors including healthcare and the environment.
Biotechnology
NPL's Biotechnology Group specialises in the measurement of biomolecules and the study of their interactions in solution, at interfaces and inside cells.
Chemical Metrology
NPL provides world-class research, consultancy, calibrations and specialised measurement services in chemical metrology.
Composites and Polymeric Materials
The Composites and Polymeric Materials Group use a broad range of measurement technology to understand material behaviour, supporting businesses of all sizes.
Electrochemistry
NPL's multi-disciplinary Electrochemistry team undertakes ground-breaking research in measurement and modelling of electrochemical and charge transfer processes.
Electromagnetics
NPL maintains one of the world's most comprehensive national capabilities for measuring electromagnetic quantities across the spectrum from DC via RF and microwave up to terahertz frequencies and beyond.
Electronics Interconnection
NPL's multidisciplinary team undertakes research in a number of disciplines across interconnect systems.
Engineered Materials
The Engineered Materials group at NPL use a wide range of techniques to understand product performance and the relationship between a material's properties and structure.
Engineering Measurement
Innovative engineering measurement methods that are key in underpinning the current and future competitiveness of UK industry, including length, mass, force and temperature and humidity.
Environmental Measurement
Accurate measurements play a vital role in gauging the scale of anthropogenic and naturally driven effects, pollutant concentrations and the development of strategies to mitigate short and long-term impacts.
Ionising Radiation
Radioactivity and radiation measurements are fundamental in a large group of activities and their use is expanding.
Mathematics & Scientific Computing
NPL is active in areas of mathematics and scientific computing which support measurement science, with research work carried out in the Mathematics and Modelling for Metrology Programme (MMM).
Mass & Force
Measurements of mass, force, pressure, and density are some of the most commonly made in the UK. NPL ensures that these measurements can be made traceable to internationally agreed standards.
Optical Radiation & Photonics
In optical science and technology, NPL is directing research effort into science areas which are central to communications, healthcare and climate change.
Quantum Phenomena
At NPL we undertake world-leading fundamental research into new areas of measurement science, particularly those that exploit quantum mechanical phenomena.
Surface & Nanoanalysis
At NPL, our Surface & Nanoanalysis research is focused on innovation, trade, industrial competitiveness and quality of life.
Temperature & Humidity
Our experienced team provides world-leading research into the development of innovative sensors, standards and measurement solutions, maintains ITS-90 and delivers calibrations against UK National Standards.
Thermal Performance
NPL's Thermal Performance team provides a wide range of measurement facilities for characterising thermophysical properties of materials and the heat transfer within engineering structures.
Time & Frequency
Home of the nation's atomic time scale, NPL is the focus for time and frequency measurements in the UK.
Science Case Studies
Science Lectures
A series of lectures given by NPL scientists or external speakers designed to inspire and inform us about the amazing research done both at NPL and other institutions worldwide.
Science stories
Measurement in 2020
Kamal Hossain, Director of Research and International, outlines in QMT magazine, how NPL is rising to meet the measurement challenges of the next two decades.
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Order from disorder
Collaborative research into a protein associated with Parkinson’s disease explores a novel way of organising proteins at the nanoscale.
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Radiotherapy doses to be more accurate
Collaborative research on the distribution of charged particles during treatment will contribute to safer radiotherapy for cancer patients.
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The tick-tock of the optical clock
A new frequency measurement in an ytterbium ion could form the basis for the next generation of optical atomic clocks.
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Commercial Services
Commercial Services
NPL's commercial services are built on 100 years of leadership in accuracy, innovation and scientific research. Experienced consultants and project managers draw upon a unique combination of industry know-how and world-leading scientific discovery to deliver real-world business solutions and enable innovation and secure competitive advantage.
Sectors
Our customers cover a wide range of sectors, technologies and applications. You will be amazed at the breadth of our services, built on 100 years of leadership in accuracy, innovation and scientific research. Below we've highlighted some of our sectors.
Products & Services
Experienced consultants and project managers draw upon a unique combination of industry know-how and world-leading scientific discovery to deliver real-world business solutions and enable innovation and secure competitive advantage. Simply use the plus buttons to learn more about a product or service.
Measurement Services
NPL Measurement Services are designed to meet the most challenging measurement requirements and to give customers the technical edge needed to be truly world-class.
Our Clients
Case Studies
NPL produces a wide range of case studies highlighting our capability and the sectors we operate in.
Insights
A magazine from NPL that explores how the science and technology community in the UK can come together to deliver world class science that can change the way we live our lives and do business, influence government funding and policies while continuing to deliver value for money.
Testimonials
Thanks to NPL Training, the measurement associates are now thinking out of the box. We are already seeing a faster turnaround of measurement activities with higher accuracy and increased confidence. NPL is known for its technical expertise in this area, and can provide the highest level validated training. It's added to our professionalism and improved communication with our suppliers.

Mark Imms
Metrology Manager
Bentley Motors

NPL has provided us with very valuable services, which have helped ensure that our satellites offer the accuracy needed provide our customers with technology they can trust, and remain ahead of our competitors.

Dr Martin Unwin

Head of GNSS/GPS Team
Surrey Satellite Technology Ltd

BP Exploration has continued to benefit from NPL's world class corrosion testing and modelling capabilities in 2009, and we intend to cooperate even more closely in 2010 and beyond.

Steve Groves
Programmes Manager
Inherently Reliable Facilities Flagship BP
Educate + Explore
Educate + Explore
We strive to actively promote public awareness and appreciation of science and technology, particularly the importance of measurement and the role of NPL. Here you can find out more about the interesting things we do, science outreach activities you can get involved in or take a look at some of our educational resources.
Schools Posters
NEW! A selection of posters for the classroom to support science and maths teaching at primary and secondary schools.
Be amazed
Be amazed by NPL's science.
Factsheets
Our factsheets are designed as a quick introduction to a subject that you can read online or download.
What is the time?
Here at NPL, atomic clocks keep UK national, and international time ticking. Our scientists are developing ways to measure time ever more accurately. This page links to general information about the world time system, atomic clocks and synchronising UK time.
Online Barograph
The NPL online barograph has been recording the pressure in Teddington, UK, since 1st January 1998.
Protons for Breakfast
A 6-week course for people interested in science and its impact on our lives.
Measurement Units
Water Rocket Challenge
Information on how to build a water rocket and also on entering NPL's annual Water Rocket Challenge.
ReactFast
Find out about measuring reaction times and take the ReactFast challenge.
Redefining the kilogram
Stored in a basement at NPL is the UK’s National Standard Kilogram, a copy of the international prototype and the standard for all mass measurements in the UK. But researchers at NPL and elsewhere are working hard to make the international prototype obsolete.
Physics Handbook
This useful physics handbook produced in association with the Institute of Physics (IoP) is an excellent resource for physics students and teachers.
Students Area
Science related material of use to students.
Virtual Physical Laboratory (VP Lab)
The Virtual Physical Laboratory (VPLab) software contains over 180 interactive experiments for use by teachers and by pupils individually.
The NPL Academy
The NPL Academy gives GCSE students a real taster of work at the UK's leading measurement research laboratory.
The NPL School Science Film Challenge
Can you make a great science film? Find out more about NPL's School Science Film Challenge.
Turing
The work Alan Turing did on the Automatic Computing Engine (ACE) while based at NPL placed us as one of the world leaders in computing development in the 1940s and 1950s.
Electron Trees
An Electron Tree is a small Perspex block which has been internally fractured by electrons escaping through a tiny break in the Perspex's base.
Outreach Activities
Protons for Breakfast
A 6-week course for people interested in science and its impact on our lives.
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The NPL Academy
The NPL Academy gives GCSE students a real taster of work at the UK's leading measurement research laboratory.
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The NPL School Science Film Challenge
Can you make a great science film? Find out more about NPL's School Science Film Challenge.
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NMS Learning Zone
Measurement Network
Measurement Network
The Measurement Network is the UK’s national network set up to support businesses to solve measurement challenges, increase the spread and adoption of measurement knowledge and address strategic measurement issues.
Biotech & Healthcare
For people involved in the biotechnology and healthcare industries that have an interest in detection, characterisation and measurement.
Communications & Electromagnetics
This special interest group brings together those interested in communication technologies and in electromagnetics.
Engineering & Optical
Reflecting a range of interests from a number of sectors, including advanced manufacturing and engineering, transport and energy.
Environment & Energy
Providing a focus for those working in the energy sector encompassing fossil fuels, nuclear and renewable energy technologies.
Ionising Radiation
Established to provide a focus for those whose work involves any aspect of ionising radiation, including dosimetry, radiation and neutron metrology.
Materials & Surface Analysis
For people with an interest in materials and surface analysis, including nano technologies.
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