Please choose the correct solution to the question: To boil water in a saucepan,

Solution1: fill a saucepan with water, turn the stove on to high heat, and when the water bubbles up in large bubble rapidly to the surface, it has boiled.

Solution2: fill a saucepan with water, turn the stove on to high heat, and when the water bubbles up in tiny bubbles close to the pan's surface, it has boiled.

Answer format: solution1/solution2