CHAPTER X.
EXPANSION FROM HEAT.
(Continued.)
Q. Does heat expand every thing else besides air and water?
A. Yes; every thing (that man is acquainted with) is expanded by heat.
Q. Why does a cooper make his hoops red-hot, when he puts them on a tub?
A. 1st—As iron expands by heat, the hoops will be larger when they are red-hot; and will, therefore, fit more easily on the tub: and
2ndly—As iron contracts by cold, the hoops will shrink as they cool down, and girt the tub with a tighter grasp.
Q. Why does a wheelwright make his hoops red-hot, which he fixes on the nave of a wheel?
A. 1st—That they may fit on more easily: and
2ndly—That they may girt the nave more tightly.