Question

question 4 of 10
some thermal containers have layers of materials to keep drinks cold for as long as possible. which design would help keep ice frozen for the longest period?
a. inner core of steel, no air gap, outer layer of steel
b. inner core of glass, no air gap, outer layer of plastic
c. inner core of glass, no air gap, outer layer of glass
d. inner core of glass, air gap, outer layer of glass

Explanation:

Air is a poor conductor of heat. An air - gap in the thermal container acts as an insulator, reducing heat transfer. Glass is also a relatively poor heat - conductor compared to steel. To keep ice frozen for the longest period, we want materials that minimize heat transfer into the container. A design with an air - gap and poor heat - conducting materials like glass will be most effective.

Answer:

C. Inner core of glass, air gap, outer layer of glass