Answer:
1) These bubbles are indeed air. Most water has some air dissolved in it. As you begin to heat the water, this dissolved air escapes the water.
2)The change from a fluid stage to a vaporous stage happens when the vapor pressure of the water is equivalent to the pressure of the atmosphere applied to the water. If water is boiled its kinetic energy increases and evaporation starts. After 10 minutes of boiling, maximum water is evaporated.
3)When water is boiled, the heat energy is transferred to the molecules of water, which begin to move more quickly. Eventually, the molecules have too much energy to stay connected as a liquid. When this occurs, they form gaseous molecules of water vapor, which float to the surface as bubbles and travel into the air.
