What baking equipment can tell when water is boiling?

There isn't any baking equipment that can specifically tell when water is boiling.

However, here are some common tools that can help you indirectly determine if water is boiling:

* Thermometer: A kitchen thermometer is the most accurate way to determine if water has reached boiling point (212°F / 100°C).

* Kettle with a whistle: A traditional kettle with a whistle will emit a sound when the water starts to boil.

* Observation: You can watch the water closely. It will start to bubble and steam when it reaches boiling point.

Remember, boiling point can be affected by altitude, so it's always best to use a thermometer for precision.