ANDREW LAMBERT PHOTOGRAPHY / SCIENCE PHOTO LIBRARY ANDREW LAMBERT PHOTOGRAPHY / SCIENCE PHOTO LIBRARY
Liver salts with universal indicator added. Universal indicator changes colour depending on whether it has been added to an acid or an alkali. In acidic solutions, as seen here, it turns a colour between red (strong acid) and pale orange (weak acid). In alkaline solutions, it turns between green (weak alkali) and purple (strong alkali).
Model release not required. Property release not required.