Aims: Mass is the amount of matter in an object, measured in kg, weight is a force created by gravity, it is measured in Newtons.

Outcomes: Newspaper front page about the discovery that mass and weight are different things. Students should also be able to distinguish between mass and weight, record both in appropriate units and some may be able to describe and use the relationship between mass and weight on the Earth (1kg = 10 N).

Needs: Bathroom scales, 0-1 and 0 - 10 N Newton meters, assorted masses incl. 100g and hangers.

Assessment: Through in lesson observation and discussion, responses to questions at the end of the lesson, marking of the written work. Level 4 - record mass and weight in correct units, level 5 - interconvert mass and weight in familiar situations, level 6 - can give more complex examples of mass and weight relationships.

Links: From stretching spring lesson (appreciates that a spring stretches evenly and so can be calibrated to record weight), to unit 9J gravity and space topic.

Ask some students to provide one piece of information that they learnt in the previous lesson (stretching). Show Newton meter. Q - what is inside? Why can this be used to measure weight? Ans: springs stretch evenly so can be calibrated. State aims of lesson.

Weigh a variety of masses using the 0 to 1N meters. Record results appropriately and plot a graph of the results. Use the graph to predict the weight of 100g mass & 500g mass. Extension - find the mass of several objects from their personal belongings e.g. pencil case. Must use the graph to get the answer. NB - make sure students use the newton meters the correct way round! Risks: work near centre of benches so that if masses fall, toes are safe.

Discussion - relationship between mass and weight. I use Starting Science 2 as a prompt (there is a series of cartoons that show the mass and weight of a can of beans on a journey from Earth to the Moon) Go through several other examples such as mass on different planets compared to weight, linking weight to the effect of gravity on mass. See also the story in the students section of this site.

Begin work on a newspaper front page to describe this astounding discovery. The newspaper page is to be completed for homework.