Question

Pick the INCORRECT statement.
When a liquid in a beaker is heated on a gas burner:

• A. the heated molecules become less dense and rise
• B. the colder molecules from above fall down and get heated
• C. the heat is transferred by convection
• D. the molecules of the liquid do not rise or fall
  

Answer 1

The correct option is D the molecules of the liquid do not rise or fall


When we heat up a liquid then it's molecules near the flame start vibrating faster and it expands. That is why it's density becomes slightly less.
This hotter and less dense liquid rises up and colder dense liquid falls down.
In this way the liquid heats up and this method of heat transfer is called convection.