49.3 MB (4.7 MB compressed)
5071 x 3401 pixels
42.9 x 28.7 cm ⏐ 16.9 x 11.3 in (300dpi)
GIPHOTOSTOCK / SCIENCE PHOTO LIBRARY GIPHOTOSTOCK / SCIENCE PHOTO LIBRARY
Universal indicator added to three beakers containing different solutions (left to right): acidic (vinegar), weakly acidic (distilled water) and alkaline (baking soda). Universal indicator changes its colour depending on the pH of the solution. Red indicates a strong acid, yellow/orange indicates an acid, green is neutral, blue indicates an alkali, and purple indicates a strong alkali.
Model release not required. Property release not required.