Saturday, September 19, 2026 Login Physics Technology Mathematics Space Biology Causality Science Fiction Comics Science Fun Interview Physics Can Water Be Hotter Than 100 Degrees Celsius? Written by: Jannatul Fatema Published: September 19, 2026, 01:00 Water's thermal conductivity is much higher than air Photo: Science ABC Imagine, you put a mug of water in the microwave to make tea. After three minutes, you saw the water was completely still. No bubbles. Now you dropped a tea bag into the water. Immediately, the water overflowed the mug's rim like a small geyser! The U.S. Food and Drug Administration has collected several reports of such incidents. These incidents have also mentioned severe burn injuries to people's hands and faces. The temperature of that water was over 100 degrees Celsius, yet the water was not boiling!
In school, we learned that water starts boiling at 100 degrees Celsius. After that, if heated further, water turns into steam. So how did the water in the microwave mug get hotter than 100 degrees? There's another question. Water evaporates from ponds or puddles and rises upwards. For that, molecules surely need extra energy. So, is the invisible water vapor around our homes hotter than the water in a kettle?
When water heats up to 100 degrees Celsius, it starts to boil vigorously Photo: Getty Images The answer to both questions actually lies in the same place. And to understand that, we first need to know what a thermometer actually measures.
Gas molecules move more freely. They dart around and collide with each other. What does temperature measure? Rub your two hands together. After a while, your hands will get warm. This is because the molecules in your hands start moving more due to the rubbing. Everything around us, including our bodies, is made up of countless molecules. These molecules are never completely still.
Gas molecules move more freely. They dart around and collide with each other. The actual relationship of temperature is with how fast the molecules are moving on average. According to NASA's explanation, the temperature of a gas is a measure of the 'average translational kinetic energy' of its molecules. That is, the average h
