A selection of blogs and online magazines covering mathematics and physics related issues:
Regularly updated YouTube channels on maths and physics concepts:
TV and radio series available via Box of Broadcasts:
One-off episodes on different aspects of maths and physics, all available via Box of Broadcasts:
Box of Broadcasts is a media archive service which records all free-to-view TV and radio programmes. In addition to those listed above there's a whole range of other scientific-related programmes on there too (Horizon, Wonders of the Universe, etc.). To find things you're interested in search by programme title, keyword or presenter.