CHARLES D. WINTERS / SCIENCE PHOTO LIBRARY CHARLES D. WINTERS / SCIENCE PHOTO LIBRARY
Endothermic reaction: Ammonium salts are dissolved in water. The temperature in the flask drops, and when a drop of water is placed on the piece of wood, the wood will stick to the bottom of the flask. Shot 2 of 2 in a sequence.
Model release not required. Property release not required.