(gentle uptempo music) <v ->In this year two lesson from the unit</v> "Uses of Everyday Materials," pupils build on their substantive knowledge of materials by learning that some materials can be stretchy. This means that they can be pulled to change their shape. Prior to this, pupils learned that the words we use to describe a material are called its properties, and that the properties of materials make them suitable or unsuitable for particular uses. <v ->Today we are looking at stretchy materials. </v> If a material is stretchy, it can be pulled to change its shape. Some materials are stretchy and this makes them suitable for certain uses. (children chattering) (indistinct) I'd like you to think about which objects can you find that are made of stretchy materials, and why do these objects need to be made of something stretchy. <v ->Pupils have hunted around the classroom</v> to find objects made of stretchy materials, and then shared their ideas about why these objects need to be stretched. Guided by the teacher, pupils work together to test different fabrics to find out which are stretchy. <v ->Aisha says, "We could get square pieces of each material</v> and put marbles into the middle. We can hold the corners to see if it stretches." Sam says, "We could try to pull each material and measure with a ruler how far it stretches." Do you have any other ideas how to investigate which materials are stretchy? Have a chat on your tables. (children chattering) <v ->Stretch. </v> (children chattering) (indistinct) They're going to work together to test each material, and they're going to place it next to a ruler and stretch the material out as far as they can, and then measure the length it. <v ->They line up each precut 20-centimeter length of fabric</v> next to a ruler or tape measure, try to stretch it as far as they can, and then measure the length of the stretched fabric. A paper tape measure is an excellent resource to use, as it can be marked and cut to represent the stretch length of fabric <v ->Make sure it's on the right side</v> with what we're measuring in here. <v ->Centimetres. </v> <v ->Centimetres. </v> And where do we need to make sure we start? Yeah, why do we need to start measuring at zero? <v ->Because zero is the head of it. </v> <v ->You hold it there. </v> And now I'm going to try and stretch it and we'll see. Oh, stretching a little bit, isn't it? Can you see how far we've managed to stretch that? 20 or so centimetres and 5 millimetres. Excellent. When scientists test materials, they record the results, the ones that they test in the table. <v ->Some groups of pupils may be supported</v> to use alternative methods of measuring, such as connecting cubes together to represent each stretched length of fabric. This video shows pupils as active participants working scientifically and purposefully by testing a selection of fabric materials, and recording their results in simple visual ways. In doing so, pupils develop their disciplinary knowledge of how to observe closely, use simple equipment safely, and perform simple tests. Now that pupils have carried out their simple tests to find out which materials can be stretched, they should think about what their results show, compare their findings with other groups, and ultimately answer the question, which fabric is stretchy enough to make Nana's socks? (upbeat music).