Why Do Bubbles Form When Water Boils?

In summary, when boiling water on a stove, the bubbles come from the water undergoing a phase change from liquid to vapor. There is no chemical reaction involved. The heat is applied to the bottom of the container, causing the bubbles of vapor to form there. Some of the bubbles may also come from dissolved air being released from the water. As the liquid reaches the boiling point, energy enters and causes a phase change, keeping the temperature constant. The vapor bubbles form in the imperfections on the surface of the pot or kettle.
  • #1
Nerv68
1
0
When something is boiling, like water on a stove, where do the bubbles come from? is it from some sort of chemical reaction?
 
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  • #2
If you are boiling water, you are heating it so that some of the water undergoes a phase change from liquid to vapor. There is no chemical reaction going on.
 
  • #3
Ie, the bubbles are the boiling. And the reason they come up from the bottom is the heat is applied to the bottom of the container, so that's where the bubbles of vapor form.
 
  • #4
Very small bubbles in water will initially be dissolved air coming out of solution and nucleating into bubbles, then as turbo and Russ indicated, the rest is liquid to steam transformation as the liquid reaches the boiling (saturation) point. As energy enters the liquid, the temperature will remain constant because the energy goes into a phase change (assuming the pressure remains constant).

Vapor bubbles will nucleate in the small imperfections in the surface of the pot/kettle.
 

1. How do bubbles form in boiling water?

As the temperature of water increases, the molecules move faster and start to break away from each other. This creates pockets of gas, or bubbles, which rise to the surface of the water.

2. Why do bubbles sometimes form in a ring around the edge of a pot when boiling?

This is because as the water near the edges of the pot heats up, the molecules move faster and escape more easily, creating more bubbles. As the bubbles rise to the surface, they push the cooler water towards the center of the pot, forming a ring of bubbles around the edge.

3. Do all liquids create bubbles when boiling?

No, not all liquids create bubbles when boiling. Liquids that are denser than water, such as syrup or oil, do not form bubbles because their molecules are too tightly packed together to create pockets of gas.

4. Why do bubbles sometimes form in a random pattern when boiling?

This is because the temperature of the liquid is not evenly distributed. Hot spots in the liquid will cause the molecules to move faster and create bubbles, while cooler spots will not have enough energy for bubble formation.

5. Can bubbles from boiling things be harmful?

In most cases, no. The bubbles that form during boiling are usually just pockets of gas and do not pose any harm. However, in some cases, bubbles can contain harmful gases or chemicals, so it is important to always follow safety precautions when handling boiling liquids.

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