Question

look at the diagram of the thermos bottle. based on what you know about heat transfer, which statement best explains how the thermos keeps a drink hot or cold for a long time?
thermos without reflective lining
thermos with reflective lining
conduction
convection
radiation
reflective lining
the metal walls stop all heat from moving, so the temperature inside never changes
the vacuum layer between the walls stops heat from moving by conduction and convection
the inner wall heats the outer wall, which then radiates heat away from the thermos
the plastic cap stops heat from moving by radiation, and the vacuum stops convection

Explanation:

Heat transfer occurs through conduction, convection, and radiation. A thermos has a vacuum layer between its walls. Conduction and convection require a medium (like air or solid material) for heat transfer. Since a vacuum has no particles (it is an empty space), it prevents heat transfer by conduction (which needs direct contact of particles) and convection (which involves the movement of a fluid medium). The reflective lining helps with reducing heat transfer by radiation (by reflecting heat back), but the key part about stopping conduction and convection is due to the vacuum layer.

Answer:

The vacuum layer between the walls stops heat from moving by conduction and convection.