עמוד:22

and Combining Energy Energy Transfers Transformations Until now we have dealt with the transformation of energy and with transfer of energy individually ; however , most processes involve the simultaneous transformation and transfer of energy . Examples Heating water in an electric kettle An electric kettle , which is full of water , is connected to the socket with an electric cord . The electric kettle is supplied with electricity from the power plant . The heating element in the kettle heats up , thus heating the water around it ( A heating element is a metallic conductor that heats up when electric current passes through it ) . Questions 1 . Describe in words what takes place in this process . Your description should include the power plant , the electric cord , and the electric kettle filled with water . 2 . Is this a transformation of energy , a transfer of energy , or both ? Explain . The heating of the water in the kettle is an example of a process in which energy is transferred from one body to another , as well as being converted to another form of energy . The process may be described in the following energy diagram : Solar-Powered Toy The toy on the left operates using solar cells * . A solar cell is a device built from solar cell panels that convert sunlight into electrical energy . Describe what happens to the energy in the process in both words and using an energy flow diagram . Include the Sun , the solar cells set in the watch , and the dials in your explanation . Following is a series of experiments that illustrate energy transformations and energy transfers . Solar cell ( photovoltaic cell ) : A solar cell is a device that directly converts radiation energy into electrical energy . When radiation strikes the solar cell , part of the radiation energy turns into electrical energy . The electrical energy is manifested in an electric current .

מטח : המרכז לטכנולוגיה חינוכית


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