Know that mass (a) It is acceptable to state that mass is the 'amount of stuff in an object'. does not change but Imagine floating in deep space and ask the students if they weigh less and then weight can.
ask them if there is any less 'stuff' in their bodies. Draw diagrams of spacemen on Earth and in deep space, arrows may be drawn to represent weight but mass is a scalar quantity that has no direction associated with it. (b) Show video clips of spacemen floating in space eg www.esa.int/spaceflight/education. Ask the students if they are closer to the Earth than the Moon is? The moon is pulled around in an orbit due to gravity, so how come the spacemen appear to be weightless? The answer is that they are not in fact weightless but appear to be weightless because they are constantly falling. (c) Ask students to sketch, on a mini-whiteboard, to draw a graph of mass against distance from the centre of a planet. It should be a straight horizontal line. Ask if a graph of weight against distance from the centre of a planet would look similar.