<Table> <Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (February 2012) (Learn how and when to remove this template message) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (February 2012) (Learn how and when to remove this template message) </Td> </Tr> <P> A bimetallic strip is used to convert a temperature change into mechanical displacement . The strip consists of two strips of different metals which expand at different rates as they are heated, usually steel and copper, or in some cases steel and brass . The strips are joined together throughout their length by riveting, brazing or welding . The different expansions force the flat strip to bend one way if heated, and in the opposite direction if cooled below its initial temperature . The metal with the higher coefficient of thermal expansion is on the outer side of the curve when the strip is heated and on the inner side when cooled . </P> <P> The sideways displacement of the strip is much larger than the small lengthways expansion in either of the two metals . This effect is used in a range of mechanical and electrical devices . In some applications the bimetal strip is used in the flat form . In others, it is wrapped into a coil for compactness . The greater length of the coiled version gives improved sensitivity . </P>

Explain the working principle of bimetallic strip thermometer
find me the text answering this question