Boiling happens when a liquid becomes gas forming bubbles inside the liquid volume. If bubbles are not formed we are talking instead about "evaporation".
The temperature at which boiling happens is called the boiling point and depends on the particular nature of the substance.
For example, water boils at around 100 °C (Celsius degrees). When water is boiling, it transforms into a vapor called water vapor.
- Food can be cooked by boiling.
- Germs in a liquid (for example, water) can be killed by boiling the liquid.
- Germs on an object can be killed by putting the object in boiling liquid.