(gentle music) <v ->In this year five lesson</v> from the unit "Forces, including Simple Machines," pupils expand their substantive knowledge of pushes and pulls by learning how forces can be measured using a force metre. Prior to this, pupils learned that a force is a push or a pull, which can change the speed or direction of an object or alter its shape. In this lesson, they learned that force is measured in Newtons using a force metre. <v ->Go on, Isaac. </v> Isaac Newton. Absolutely perfect. <v ->So there's a scale on the side what is in Newtons,</v> and when you put an object on the hook, it pulls the spring down and it measure the object's weight in Newtons. <v ->Guided by the teacher,</v> they explore how a force metre works as the weight of an object stretches a spring, causing a marker to move down a scale. <v ->One person is going to hold</v> the handle of the force metre. What does that read in Newtons, Lucas? <v ->20. 5. </v> <v ->Oh, 20. 5. Well done. </v> <v ->Pupils observe that the greater the force,</v> the more the spring stretches and the higher the number of Newtons. This video shows pupils as active participants, working scientifically and purposefully by using various force metres to measure everyday objects' pulling force or weight due to gravity. They measure to the nearest 0. 5 Newtons by reading the number aligned with the top of the marker on the scale. <v ->The marker, which is at the top here,</v> has like a top and a bottom. You would have to read the very, very, very top of the marker. <v ->So what you do is like, you can put an object on it</v> and then like you read it from the top of the marker, like these scissors to say 0. 5 Newtons. <v ->In doing so, they develop their disciplinary knowledge</v> of taking accurate measurements using scientific equipment. Now that pupils can identify and correctly use a force metre, they should be given further opportunities to select the most appropriate scale when measuring forces of different magnitudes. The aim is for pupils to gain confidence in using a force metre to measure and compare forces in the context of inquiry. For example, by measuring the force required to move an object across various surfaces when investigating friction. (upbeat music).