Glass has a specific heat of 0.84 j/g·° c. copper has a specific heat of 0.39 j/kg·° c. which material takes more energy to warm up?

The higher the specific heat capacity level, the more energy it requires to warm it up by 1°C.
Since the unit for the given numbers are different, simply multiply 0.84 by 1000 so that we can know the specific heat capacity of glass is 840 J/kg·°
Comparing both numbers, the value for glass is larger.
Therefore, glass requires more energy to warm up.

It shows that the experiment is designed properly.

16- counting by fours