Final answer:
The shiny surfaces on thermoses do block the loss of heat energy through radiation.
Step-by-step explanation:
The statement is True. The shiny surfaces on thermoses block the loss of heat energy through radiation. Thermoses are designed to inhibit all methods of heat transfer, including conduction, convection, and radiation. The shiny surface on the thermos, often made of reflective silvering, reduces the amount of thermal radiation that can escape. This helps to keep the contents of the thermos hot or cold for longer periods of time.