When is grandpa capitalize?

All Words are capitalized at the begin

ni

ng of the se

nte

nce, commo

n

nou

ns a

nd proper

nou

ns i

ncluded. Gra

ndpa

is a commo

n

nou

n but it is capitalized

whe

n it is used as a direct address.

Example:

Are you home, Gra

ndpa?