Why does thermometer mercury sometimes look red?
The silvery thread of thermometer mercury fails to perform when the temperature falls below a certain level. But this low down problem did not stump our clever gadgeteers for very long. They simply substituted a substance that has a lower melting point than silvery, metallic mercury. And they colored this temperature measuring material red. A thermometer that registers temperature with a thread of red material depends upon a thin column of alcohol. Since this liquid material is watery clear in its pure form, it would be invisible inside the glassy clear thermometer tube. So some wid. A thermometer that registers temperature with a thread of red material depends upon a thin column of alcohol. Since this liquid material is watery clear in its pure form, it would be invisible inside the glassy clear thermometer tube. So some wide awake designer thought of staining the colorless liquid red. This simple addition made the red thread clearly visible beside the precise ladder of degrees on the
