(b) The figure below shows a paddle wheel placed in a beaker containing water. When the water is heated at the point indicated, the wheel rotates. Paddle wheel Water HEAT i. Explain why the wheel rotates (2mks) ii. State the direction in which it rotates (1mk) (c) A vacuum flask is designed to keep a liquid hot for a long time. Explain how heat losses are reduced in a vacuum flask (3mks) 19) (a) Define density (1mk)