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What are those bubbles/lines on the surface of my (clean) teacup after making tea with a tea bag (seethrough paper kind, wrapped in paper)? I used a kettle. The water is clean. Also what determines these patterns?

They have dissipated over 5 minutes or so.


1 Answer 1


It is most probably the air trapped in the spaces between the powdered tea leaves that is slowly escaping. That's why they appear almost immediately when you dip the teabag in warm water and disappear. You will get the same types of bubbles if you mix mud and water. Explaining the pattern is a little bit difficult. Assuming that you didn't stir anything since these patterns also depend on the way you stirred your tea.

Tea leaves are not as soluble as mud so they tend to dissolve slowly. Assume that there are bunch of teabags inside the first tea bag.Water seeps into the first layer, and the displaced air bubbles travel upwards along the same surface and thus merge at the same place(top of the tea bag and form a line) creating a line of air bubbles. Then water seeps into the next layer and the same thing happens and another group of air bubbles are formed are it goes on till the whole tea hasn't been dissolved. This produces groups of air bubbles.

Also what determines these patterns?

  1. Shape of the teabag
  2. Size( small teabags means less air is trapped between tea particles)
  3. Solubility of different types of tea

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