More on how to do the calculations is in the SPT: Electricity and energy topic. In neither case is it particularly easy to calculate the amount of energy shifted at this early stage, but by way of compensation the mechanisms for these two pathways are looked at in detail in episode 05. Hot things can shift energy to another internal store in two different ways by radiation and by particles. For example, energy is shifted to the thermal store of the surroundings when charge passes through the resistive filament wire of a bulb, and we can measure the voltage drop with a voltmeter connected across the bulb. Put briefly, energy is shifted through electrical working when charge passes through a voltage. ![]() The energy shifted by electrical working can also be calculated and that has an episode all to itself (SPT: Electric circuits topic). These calculations are further ahead in the pupils' learning, and are presented for completeness. Furthermore, thinking back to the ideas of episode 03, the energy is shifted along a mechanical working pathway. In both cases energy is shifted from the chemical store of your muscles to the gravitational store of the stool or book in the Earth's field. For example, how much energy is shifted when you lift a stool up onto the bench at school? How does this compare with the energy shifted when you lift a book up onto a shelf? Thinking about lifting things is a good place to start investigating the how much? question. ![]() We are therefore including much of the material in this episode to allow you, the teacher, to develop a broader and deeper understanding of the topic. Being able to answer this question is of great practical importance, whether in designing car engines, estimating the energy demands of a city or thinking about the insulating properties of a new material.Ĭalculating energy changes is not required of pupils in the 11–14 age range, although it certainly is during the next stage of schooling. Annual power usage in kWh 620500 Wh /1000 620.5 kWh / year. Annual power usage in Wh 1700W x 1 Hours x 365 days 620500 Wh / year. Calculate the energy consumption in Wh and kWh in one year. ![]() Now we turn our attention to the question of how much energy is being shifted. Power Consumption (Annual) Power Usage (Watts) x Time (Hours) x 365 (Days) Example: A 1700 Watts Electric kettle runs for 1 hours daily. So far we have introduced an energy perspective, seeing processes as shifting energy between different kinds of stores and along various pathways.
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