Casement window, with latticed lights. A casement is a window that is attached to its frame by one or more hinges. Casement windows are hinged at the side. Windows hinged at the top are referred to as awning windows, and ones hinged at the bottom are called hoppers.
Open Systems. The ocean is an open system. The ocean is an example of an open system. The ocean is a component of the hydrosphere and the ocean surface represents the interface between the hydrosphere and the atmosphere that lies above. Solar radiation passes through the atmosphere and is absorbed by the ocean.
Earth is considered a closed system because though heat enters, its mass remains essentially constant. The matter of Earth remains on Earth and in its atmosphere because gravity prevents it from migrating into space. Earth is also considered to be more of an approximation of a closed system because some matter does enter from space.