What is the most likely reason that the red liquid inside of a thermometer moves up when it is heated? A. The particles in the red liquid move faster and come together. B. The particles in the red liquid move faster and spread apart. C. The particles in the red liquid move slower and come together. D. The particles in the red liquid move slower and spread apart.
B. The particles in the red liquid move faster and spread apart.
When a substance is heated, the particles within the substance gain energy and move faster, causing them to spread apart and increase in volume. This expansion of the liquid causes it to move up the narrow tube of the thermometer.