Page 33 - Science Class 07
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              Heat Flow and Temperature









               •  Heat                             •  Temperature              •  Transfer of Heat
               •  Conductors and Insulators        •  Thermos Flask


              Energy is the process we call heat or heat flow        etc.  This  form  of  energy  also  plays  a  very
              and  is  constantly  flowing  into  and  out  of  all   important role in nature. The occurrence of the
              objects,  including  living  objects.  Heat  flow      wind,  rain,  change  of  seasons,  etc.  is  all
              moves energy from a higher temperature to a           dependent  on  the  gradient  created  due  to
              lower  temperature.  The  bigger  the  difference      uneven  hea ng  of  different  regions.  Here,  we
              in temperature between two objects, the faster        will  learn  about  the  concept  of  heat  and  the
              heat flows between them.                               classifica on of objects into hot and cold.

              When  temperatures  are  the  same  there  is  no     With the increase in temperature of a body, the
              change in energy due to heat flow.                     vibra ons  of  molecules  or  atoms  increase.
              Energy flows into your body from the surroun-          These vibra ons are then transferred from one
              ding air, from surrounding objects and from the       part  of  the  body  to  another.  The  measure  of
              sun  when  you’re  outside  or  even  light  bulbs    energy  with  which  the  molecules  vibrate  in  a

              when  you’re  inside.  Energy  also  flows  out  of    system is termed as heat stored in that object.
              your  body  into  the  surrounding  air,  into  the   It flows from a body at higher temperature to a
              surrounding objects and even into outer space,        body  at  a  lower  temperature.  This  is  because
              most  notably  if  you  are  outside  on  a  clear    the  molecules  vibra ng  faster  transfer  their
              night.                                                energy  to  the  molecules  vibra ng  slower.  The
                                                                    vibra onal  energy  is  also  termed  as  its  heat
                                    HEAT
                                                                    content. The heat content in the body makes it
              Heat is one of the essen al forms of energy for       hot  or  cold.  Greater  the  heat  content,  ho er
              the survival of life on the earth. It plays a major   will be the body.
              role  in  our  lives.  We  use  heat  energy  for
                                                                    The French scien st Jacques Charles discovered
              cooking,  ironing,  transporta on,  recrea on,
                                                                    that heat could be transformed into mo on.




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