Improve Heat Control Practice Test

A hot-water container uses foam insulation. The student can increase the foam thickness from 2 cm to 4 cm. If heat loss through the walls is mostly by conduction, what is the best prediction about the conduction heat transfer rate through the walls when thickness doubles (all else equal)?​​​

A hot-food container cools too quickly. Current design: 0.5 cm plastic walls, loose lid, plain interior. Test: 70°C to 52°C in 2 hours (failed the ≥60°C criterion). The student has time to make only one change before retesting. Which single change is most likely to make the biggest improvement for the least cost, based on the data suggesting steady heat loss through the sides over hours?