Skip to main content
Skip to navigation

Purest silicon sphere ever created will redefine the kilogram

By Chemistry World2017-06-26T10:16:00

Purest silicon sphere

Source: Enrico Massa and Carlo Sasso

Largest impurity is copper taking the place of one silicon atom in every three billion

Purest silicon sphere ever created will redefine the kilogram was first published by Chemistry World.

Make your lessons pop

Choose an account option to continue exploring our full range of articles and teaching resources

Register for a personal accountFree

Free

Free access for everyone, everywhere. If you only need a few resources, start here.

What's included

One free teaching resource each month
Five free Education in Chemistry articles each month
Personalised email alerts and bookmarks

Register now

UK and Ireland only

Join Teach ChemistryFree for eligible users

Free for eligible users

Free and comprehensive access for teachers and technicians at secondary schools, colleges and teacher training institutions in the UK and Ireland.

What's included

Unlimited access to our resources and practical videos
Unlimited access to Education in Chemistry articles
Access to our online assessments
Our teacher well-being toolkit and personal development resources
Applications for funding to support your lessons

Sign up now

Subscribe for extended access£80 per year

£80 per year

Get unlimited articles and resources each month, plus discounts on professional development courses.

What's included

Unlimited access to our resources and practical videos
Unlimited access to Education in Chemistry articles
10% off our self-led professional development courses

Subscribe now