Turnips
Pumpkins are used to carve jack-o-lanterns.
we carve jack o lanterns because stingy jack tricked the devil into going to hell and the smile is to represent jack's smile when he did
for Halloween decorations
The Irish carried the Hallow's Eve tradition with them. They would originally carve out squash-like vegetables and make lanterns out of them. The only squash-like ones they had in America were pumpkins. A native (of America) saw them and called it a Jack O' Lantern. Then it stuck.
Pumpkins are used to carve jack-o-lanterns.
Because it looks scary
Actually jack-o-lanterns can be made out of any fruit or vegetable; it's just that pumpkins are large, and easy to hollow out and carve faces on.(It is believed that the first jack-o lanterns were made from turnips)
The English and Irish used potatoes and beets to carve scary faces on. Once they immigrated to America, they discovered the pumpkin (native to America) and found it was much better suited to carving.
The Irish carved jack-o-lanterns out of turnips and rutabagas. The Welsh and Briton did this too. It was nailed to their doors to ward off angry spirits.
Ireland used Turnips as "Jack "O" Lanterns"
pumpkins
Turnips were carved instead of pumpkins.