Privacy and cookies

You’re reading our privacy and cookies page so we’ll assume that you’re concerned about your online privacy. We are too. That’s why we’ve produced this page to explain exactly what’s happening (and what can happen) on our site.

Our principles

Here at physicsfocus we’re passionate about being as transparent as possible. We hold a few basic principles about privacy:

  • We won’t ask you for personal information unless we truly need it
  • We won’t share your personal information with anyone (except to comply with the law)
  • We aim to make it as simple as possible for you to control the information we get from you

Your email

On physicsfocus there are 3 instances where you could submit your email to us:

  • When leaving a comment
  • When registering for email updates
  • When getting in touch

In each case your email address is stored securely on our server. We can see your email but will only ever use it if you ask us a question and we need to get back to you or if you subscribe to updates. This is a blog about physics. We’re not interested in selling you stuff. And we know how full your inbox is already! If at any point you wish for your email address to be removed from any of these systems just drop us a message.


If you comment using an  email address you have linked with the avatar service Gravatar, then the picture used on your Gravatar account will be displayed alongside your comment.  Of course, you should be especially aware of this if you wish to post anonymously.


We use cookies on physicsfocus to analyse activity on the site and to enable some functionality. You can find a list of all the cookies on physicsfocus below. We aim to keep this list up to date all of the time but because we use third party services, it’s possible the list could become out of date without us knowing about it. We’ll try not to let this happen. Something you should know before you read this list: we don’t use any cookies for advertising purposes. All our cookies are there to make our site the best possible experience for you. So, there are two types of cookie you may encounter when using this website: First party cookies: these are our own cookies, controlled by us and used to provide information about usage of our site. Third party cookies: these are cookies found in other companies’ tools that we use to make our site better. For example, Facebook or Twitter have their own cookies, which are controlled by them. Here’s what we’ve got:


Name Purpose
wordpress_ WordPress cookie for a logged in user.
wordpress_logged_in_ WordPress cookie for a logged in user.
wordpress_test_ WordPress cookie for a logged in user.
wordpress_test_cookie WordPress test cookie.
wp-settings- WordPress also sets a few wp-settings-[UID] cookies. The number on the end is your individual user ID from the users database table. This is used to customize your view of admin interface, and possibly also the main site interface.
wp-settings-time- WordPress also sets a few wp-settings-{time}-[UID] cookies. The number on the end is your individual user ID from the users database table. This is used to customize your view of admin interface, and possibly also the main site interface.
PHPSESSID To identify your unique session on the website.
SESS To ensure that you are recognized when you move from page to page within the site and that any information you have entered is remembered.


km_ai, km_lvThese cookies are used by Hittail and help us with serach engine optimization.

Name Purpose
Cookies with names prefixed by __utm Stores information used by Google Analytics to track user activity on the site.
_chartbeat2 We use Chartbeat to help us monitor our webstats in real time. This cookie is used to determine if you are a new or a returning visitor
_SUPERFLY_nosample This is used by Chartbeat to monitor how much we use the service.
pid, k, guest_id, _twitter_sess, original_referer,external_referer, js, Twitter cookies which allow content from Twitter to be shown on website pages and pages to be shared on Twitter.
datr, lu, s, locale, c_user, xs Facebook cookies which allow sharing of a page on Facebook.

If you have any questions or concerns about the cookies use on this site feel free to drop us a line and we will do our best to help.

If you would like to block the third-party cookies we use, then we recommend Ghostery, a service that lets you control which trackers you allow.