full episodes downton abbey

Astronauts far from the Earth are so little challenged by gravity that they can float, but Rob asks, what happens as you go in to the centre of the Earth - do you get heavier?

Lithography was an old method of printing using lithographic stone and the fact that water and wax don't mix. Rob shows how it works, and how you can try it yourself with an unglazed tile, a crayon and food colouring.

Astronauts far from the Earth are so little challenged by gravity that they can float, but Rob asks, what happens as you go in to the centre of the Earth - do you get heavier?

Lithography was an old method of printing using lithographic stone and the fact that water and wax don't mix. Rob shows how it works, and how you can try it yourself with an unglazed tile, a crayon and food colouring.