Question

Liquids and gases expand when heated, which causes _____. Question 19 options:

heat transfer by conduction.
convection currents in fluids due to constant temperatures.
convection currents in fluids due to changing densities.
convection currents in fluids due to changing masses.

Answer 1

the answer is heat transfer by conduction because its like heating up hot air balloon for example

Answer 2

When we heat up liquids and gasses it expands

density of material decreases as space between particles increases

so it become less dense

and we also know that less dense liquids and gasses comes at the top and more dense comes at the bottom

so when we heat up liquid and gasses become less dense and move up and other part of liquid and gas which was not heated comes down

this process is called convection

and it produces convection currents

so here third option is correct

convection currents in fluids due to changing densities