(soft bright music) <v ->In these year six lessons from the unit,</v> "Light and How It Travels," pupils develop their substantive knowledge by learning that we see when light travels into the eye or when light is reflected from an object into the eye. Prior to this, pupils learned that objects that produce light are called light sources, and that light travels outwards in straight lines from a light source in all directions. <v ->How does light travel?</v> Where does it travel from? Where does it start? Ah, Ramon. <v ->From a light. </v> <v ->From a light. </v> <v ->Source. </v> <v ->Source, from a light source. </v> Good, so can you point to a light source for me? <v ->In this lesson, the pupils further</v> their understanding of how light travels. They learn that scientists use models to describe things that can't be experienced directly and often record information using a type of drawing called a diagram. This video shows pupils as active participants using models to show that we see things when light travels into the eye, and that seeing anything that is not a light source relies on the reflection of light. Using wool or string in their physical models helps pupils to understand that the wool must be pulled tight, because light travels in straight lines. It also helps them to see that the wool must safely touch the torch, an object, and the person's eyes as we see things when light enters the eye. <v ->What do we need to remember when we're drawing</v> the journey of the light? Ariana. <v ->It has to be straight lines. </v> <v ->It has to be straight lines,</v> which is why I've gotta ruler, excellent. <v ->So I'm pulling the string really tight</v> because light travels in straight lines. <v ->Pupils continue to work scientifically</v> and with purpose to record their models using scientific diagrams. This provides the perfect opportunity for them to apply their procedural knowledge they have developed. Pupils learn that objects are drawn in 2D from the side and are not coloured in. Light rays are drawn as straight lines using a ruler. Rays must touch the object to show that light reflects off its surface. Each ray must have an arrowhead in the middle indicating the direction the light is travelling. Pupils must also remember that these diagrams show just one line of travel, even though light travels from a light source in all directions. The range of activities in these lessons provides excellent opportunities for pupils to develop their disciplinary knowledge of how to record and represent information using models and scientific diagrams. Pupils should continue to develop their understanding of how light travels by drawing and using a range of scientific diagrams to show how we use reflected light to see objects in our everyday lives. Next, they should begin to explore how reflective materials are used to change the direction in which light travels. They can also plan an investigation to see how changing the angle of a mirror affects the angle of reflected light. (soft upbeat music).