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Task 2:



Task 3:


 * 6. Discuss your findings and reflections in part (4) & (5). Also discuss where did the heat energy go? (Is it really wasted?)**

As shown, the amount of energy wasted is approximately 20 MJ every time we use a conventional stove to pop ¼ cup of corn. This also means that by just popping corn, we have wasted energy which could have been used to power a 100W bulb for more than two days straight! In that short 4 minutes of popping corn, we have caused a huge amount of wastage. Using microwaves to pop corn would also waste 15 MJ of energy, enough to power the same 100W bulb for nearly two days.

The wasted energy is used to heat the air and surroundings, like the stove and pan. In microwaves, energy is absorbed by the walls of the microwave oven, which is then dissipated into the air. This unnecessary heating up will result in more natural resources being used up. And because generation of energy using fossil fuels usually involves combustion, increased energy production increases carbon dioxide emissions and other pollutants, thereby causing the greenhouse effect and global warming.


 * 7. Research shows that in developed countries like Singapore, electricity generation is only 34% efficient with respect to the energy content of the fuels burned, compared with the electrical energy delivered to the home. Do a calculation of "overall" or "global" efficiency taking this indirect energy loss into account. Also calculate how many joules of energy must be obtained from natural resources to pop corn.**

__Conventional stove__: Overall efficiency of energy used to pop corn = Energy needed / Energy produced Energy produced * 34% = Energy supplied Energy produced = 20,160,000 J / 0.34 = **59 MJ** Hence, Overall efficiency = 75020.14 J / 59,294,120 J = 0.13%

__Microwave__: Overall efficiency of energy used to pop corn = Energy needed / Energy produced Energy produced * 34% = Energy supplied Energy produced = 15,660,000 J / 0.34 = **46 MJ** Hence, Overall efficiency = 36486.39 J / 46,058,820 J = 0.079%