Leave a block of wood and a brick of steel in a freezer for 24 hours and see which one feels cooler - they’ll be the same actual temperature (at least negligibly close the longer they’re left) but the metal will feel immensely cooler to the touch due to its higher capacity for heat transference.

There are two compounding factors

• heat capacity: any short term experiment will measure heat capacity first, conduction second

• locality of contact: contact along the whole length of the straw eliminates heat conduction along the length of the straw. A single point of contact (holding the straw with fingers instead of the whole hand) behaves differently.

I thought plastic straws were thinner than 0.2 mm, so maybe the metal is actually better.

It's fun arguing about these technicalities though!