4962 /www/nrich/html/content/id/4962/ 1 2011-02-01T00:00:01 <?xml version="1.0" encoding="UTF-8"?> <mdoxml version="1.0"><br></br> Arrange these shapes in order of size. Put the smallest first.<br></br> <br></br> <div style="text-align: center;"><mdo:image width="500" height="389" src="irreg.gif" alt="seven irregular shapes"></mdo:image></div> <div>You might like to use this interactivity to try out your ideas:</div> <br></br> <a href="/content/id/4962/OrdSh2.swf">Full screen version</a><br></br> <mdo:flash height="400" width="550"><param value="/content/id/4962/OrdSh2.swf" name="movie" ></param><param value="7" name="flashplayerversion" ></param><param value="400" name="height" ></param><param value="550" name="width" ></param></mdo:flash><br></br> <br></br></mdoxml> <?xml version="1.0" encoding="UTF-8"?> <mdoxml version="1.0"><br></br> <p><span class="editorial">It was interesting to see how you decided what we meant by &quot;size&quot;. Kelsey from Sutton Primary School (with the help of his cousin Michaella) measured the length of each shape at the longest point (I am guessing that he printed them off first.). He says:</span></p> The order is green ($11$ cm), red ($12.5$ cm), yellow ($13$ cm), blue ($13.5$ cm), orange ($15$ cm), purple ($16.5$ cm) and lastly grey ($18.5$ cm).<br></br> <br></br> <p class="editorial">Louise and Rosie from Fulford had a different strategy. They wrote:</p> We observed the area of each and tried to rearrange the shapes in our heads to compare them. This is the order in which we think the shapes go: (smallest to largest) Green, Purple, Red, Light Blue, Yellow, Orange, Dark Blue.<br></br> <br></br> <p class="editorial">So, Louise and Rosie have a slightly different answer from Kelsey, but more importantly, they each explained how they tackled the problem.</p> <p class="editorial">Thomas from St Peter's had a different strategy again, and a slightly different order:</p> Green, Red, Purple, Yellow, Blue, Orange and Grey the same size. I cut out the shapes then cut each up into little pieces and laid them on top of each other to see which was bigger. I also put them on a grid with small squares and counted the number of squares for each, this gave the same answer. <p class="editorial">Perhaps you found a different way again to measure &quot;size&quot;?</p> <br></br></mdoxml> <?xml version="1.0" encoding="UTF-8"?> <mdoxml version="1.0"><div class="embed"> <h2>Sizing Them Up</h2> <br></br> Arrange these shapes in order of size. Put the smallest first.<br></br> <br></br> <div style="text-align: center;"><mdo:image alt="seven irregular shapes" height="389" src="irreg.gif" width="500"></mdo:image></div> <div>You might like to use this interactivity to try out your ideas:</div> <br></br> <a href="/content/id/4962/OrdSh2.swf">Full screen version</a><br></br> <mdo:flash height="400" id="/content/id/4962/OrdSh2.swf" width="550"><param name="allowfullscreen" value="true"></param><param name="movie" value="/content/id/4962/OrdSh2.swf"></param> <param name="flashplayerversion" value="7"></param> <param name="height" value="400"></param> <param name="width" value="550"></param> </mdo:flash><br></br>  </div> <br></br> <h3><span style="font-weight: bold;">Why do this problem?</span></h3> <a href="http://nrich.maths.org/public/viewer.php?obj_id=4962&amp;part=index">This activity</a> is designed to help children begin to understand the meaning of area as a measurement of surface. It gives them a chance to choose and then justify a way of measuring.<br></br> <h3>Possible approach</h3> <div>This activity is deliberately open to encourage children to try to define "smallest" for themselves. At this level, the important point is to be able to explain and justify a particular order, rather than there being any right or wrong way to do it. Children might use criteria such as length, height or perimeter, for example. The activity should lead into the introduction of the concept of area, (even if the word "area" itself is not used).</div> <br></br> <div>You could start the activity off with a few shapes which are obviously very different "sizes" so that children will agree on an order. Invite them to explain why they ordered them in that way. After this you could use the interactivity on an interactive whiteboard to introduce the shapes in the problem or simply show them the shapes cut out from <a href="/content/id/4962/irregular_shapes.doc">this sheet</a> . After this, children could work in pairs with the shapes. Tell them that this will be harder to do than it was with the first shapes they looked at. It is important to allow plenty of time for children to share their ordering and explanations with their partners and the rest of the group.</div> <br></br> <div>There is no reason why you should not make your own irregular shapes using the activity as an idea rather than a problem to be solved.</div> <h3>Key questions</h3> <div>Why do you think this shape is bigger/smaller?</div> How are you going to decide which is smallest?<br></br> <h3>Possible extension</h3> Children could be asked cut out shapes which they think are "the same size" but which are very different shapes from those given.<br></br> <h3>Possible support</h3> Some children might benefit from cutting out the shapes from <a href="/content/id/4962/irregular_shapes.doc">this sheet</a> and putting them one on top of another to aid comparison.<br></br> <br></br></mdoxml> <?xml version="1.0" encoding="UTF-8"?> <mdoxml version="1.0"><br></br> How are you going to decide which is smallest?<br></br> How about cutting the shapes out from <a href="/content/id/4962/irregular_shapes.doc">this sheet</a>?<br></br></mdoxml> <?xml version="1.0" encoding="UTF-8"?> <mdoxml version="1.0">Green 6.5 units. Purple 9 units. Red 9 units. Yellow 10.5 units. Orange 11 units. Grey-blue 11.5 units. Bright blue 14 units.<br></br></mdoxml> 2 3 1 0 0 0 0 Can you put these shapes in order of size? Start with the smallest. Information and Communications Technology Interactivities Using, Applying and Reasoning about Mathematics Practical Activity Measures and Mensuration Perimeters Measures and Mensuration Length/distance Measures and Mensuration Area Admin Lower primary mapping document