Pandora 3: Direhorse

Facts on Water and Energy

Use your Facts link, and your graph of water saturation and temperature, to solve these problems.

1. Suppose that a front of air at 40°F containing 0.6% water vapor blows over Gambier. 

(a) What happens if the air cools to 20°F ? What is now the relative humidity?

(b) Inside your dorm, the air is heated to 70°F. What is now the relative humidity? What effect does it have on the human body?

2.  Suppose a direhorse can lose 20% of its weight in water after roaming the Pandoran forest without finding nectar. When the direhorse does find a flower fulll of nectar, it can drink enough in twenty minutes to regain its original body weight (before losing 20%). Suppose after 25 days in the forest a hungry direhorse weighing 700 kg finds a flower full of nectar.  

How much nectar would the direhorse  have to drink to restore its original body weight?

What would be its final weight after drinking?

3.  A stillsuit is used on Dune to conserve water. 

(a) Explain how a stillsuit works, and the problems to overcome.

(b) What total amount of water does a human use and lose daily? 

(c) In a stillsuit, what happens to human wastes? What is the consequence for Fremen society; what's it like to be in the underground cavern with a lot of Fremen?

4.  Suppose solar energy is used on Arrakis.  Assume the facts on your link.

(a) Today, the best photovoltaic solar panels are able to convert 20% of the available energy to electricity.  If a glowglobe uses as much electricity as a 25 Watt light bulb, how large an area of solar panels would be needed to light one glowglobe for each of the 1000 persons living in the sietch? 

(b)  Suppose a "plantoid" alien being uses photosynthesis (with 20% solar efficiency) instead of eating food. Assume a human being eats food containing 2000 food Calories per day (1 food Calorie = 4.18 kilo-Joules). What surface area (in square meters, m²) would the plantoid need to sustain itself?

5. Compare and contrast the ecosystems of Gambier and of Dune.

(a) How do materials and energy cycle in each ecosystem?

(b) What is lacking or incomplete about the Dune ecosystem?