5. Men had many ideas for telling time. One idea was to use rope made form plants. Knots were put in the rope at certain places. The rope was burned from knot to knot. The distance between knots was a certain amount of time. Another idea was to burn candles which melted from mark to mark. Usually the mark showed a half-an-hour or an hour. And finally, the hourglass was popular for telling time. Sand in the hourglass passed through a small opening from an upper glass to a glass below. The changing level of the sand marked the passing of time.