Video She takes a piece of chalk and begins writing something on the floor.

They are the remnants of dry valleys in the chalk South Downs, which are gradually being eroded by the sea.

In Tunisia and Mozambique, teachers wear white coats to protect their street clothes from chalk.

Arun Shanbhag has a post full of photographs from blood pools, to chalk marks and a burning Taj Hotel.

Chalk is a soft, white, porous sedimentary rock, a form of limestone composed of the mineral calcite.

Well, in Senegal we found that this was the traditional classroom 120 kids three per desk one teacher, a little bit of chalk.

In more than three quarters of the 120 schools visited during the mission, there were no instructional materials such as chalk, chalkboards, books, science laboratories or other teaching aids.

This student was one of our first students, and it's the girl on the left leaning with her chalkboard, and she came ... within two days I want to show you the program she wrote, and remember her hairstyle. And that is the program she made.