1. In the experiment, you assumed that all the energy in the sunlight which was incident on the collector was transformed into thermal energy in the aluminum plate. What effects might make this assumption invalid? Which of them is the most important? Can you make any quantitative estimate of how big they might be and how much they could affect the result? Do you expect these effects will make your result for the energy coming in from the sun too big or too small? How could you alter the experiment to make the effects less important? 2. Determine the solar power used in photosynthesis. It has been estimated that about 0.0757% of the solar power that reaches the Earth is captured by plants and used in the photosynthesis process. Knowing this, how much solar power is used by plants to make their food? 3. Now you can estimate the amount of food could be produced with this much sunlight, if it were all used to produce food. In The Hungry Planet, George Borgstrom, a professor of Food Science and Geography at Michigan State University, states that 10% of the solar power used by plants in photosynthesis can be used by humans as food. Determine how many watts of power this equals. 4. Knowing that one watt equals 0.24 cal/sec and one food Calorie equals 1000 calories, calculate how many food Calories could be produced on the Earth in one day. 5. Lastly, estimate the maximum population that Earth could support. The current opinion is that the normal food requirement of a full-grown person is about 3,000 food Calories per day. Since most humans eat animal products as well as plants, their intake includes the energy needed to feed the animal products they consume. 80, although the normal food requirement is about 3,000 food Calories per day, this figure increases to about 10,000 food Calories a day when the conversion of plants to animal products is taken into account. If you use a 10,000-Calorie intake as a standard, what is the theoretical maximum number of humans that Earth can suppon? 6. How does your result compare with the current population of Earth, approximately six billion? Based on current rates of growth, the global population has a doubling time of about 40 years. What are the implications of that figure based on your results? In how many years will the number of humans reach your maximum population estimate? 7. What if all humans became vegetarian (or vegan)? Go back to the final step of your analysis, and assume that all our food came from photosynthesis. This would mean that each person would need about 3,000 food Calories per day, not 10,000 Calories. If everyone was a vegetarian, how many people could inhabit the planet? How does this compare to your previous result? In about how many years will the population reach your new estimate