Question

3 a bowl of hot soup is sitting in a room. what factor would make the soup stay warm longer? choose three. placing the bowl on a cold surface putting the soup in a thermos stirring the soup with a metal spoon covering the top of the bowl placing the bowl near an open window increasing the temperature in the room

Explanation:

• "Putting the soup in a thermos": A thermos is designed to reduce heat transfer (conduction, convection, radiation), so it keeps the soup warm longer.
• "Covering the top of the bowl": This reduces heat loss by convection (heat rising from the soup) and also minimizes evaporation - related cooling.
• "Increasing the temperature in the room": Reducing the temperature difference between the soup and the room slows down heat transfer (by conduction, convection, and radiation) from the soup to the surroundings.

• "Placing the bowl on a cold surface" would increase heat loss by conduction (heat flows from hot soup - bowl to cold surface).
• "Stirring the soup with a metal spoon" would increase heat loss as metal is a good conductor, and stirring can also increase convection, speeding up heat transfer.
• "Placing the bowl near an open window" would increase heat loss by convection (cooler air from outside and air movement) and radiation (if it's colder outside), speeding up cooling.

Answer:

• Putting the soup in a thermos
• Covering the top of the bowl
• Increasing the temperature in the room