ANDREW LAMBERT PHOTOGRAPHY / SCIENCE PHOTO LIBRARY ANDREW LAMBERT PHOTOGRAPHY / SCIENCE PHOTO LIBRARY
Bicarbonate of soda toothpaste test. Piece of red litmus paper being used to demonstrate the alkaline nature of toothpaste. The alkalinity is due to the presence of bicarbonate of soda in the toothpaste. This component of the toothpaste is both an abrasive and a whitener. This toothpaste is green in colour due to mint flavouring. The toothpaste is an American brand, Arm & Hammer.
Model release not required. Property release not required.