# Calculating Energy Density from

• killbot2000
In summary, the conversation discusses the estimated weight of ungulate deaths in the Serengeti each year, the mass-specific energy content of these animals, and the land area of the Serengeti. The mean energy density is then calculated to be 31 joules per metre squared per day, but there is confusion about how this number was obtained.
killbot2000

## Homework Statement

It has been estimated that a total weight of 4x10^7 kg of ungulates die in the Serengeti each year (Houston, 1979). We assume that these have an mass-specific energy content of 7x10^6J kg^-1 (Peters, 1983), and that the Serengeti stretches over 25,000 km^2 (Sinclair and Norton-Griffiths, 1979) This gives a mean energy density of 31 Jm^-2 day^-1

## The Attempt at a Solution

I'm struggling to see how the authors get their final figure of 31 joules per metre squared per day. Presumably it's the total weight multiplied by the mass specific energy content and that divided over the land area. I don't get their answer when I do this.

Any insight would be much appreciated.

It's from the appendix of this paper http://www.sciencedirect.com/science/article/pii/S0022519304000542

No idea where I was going wrong but thanks for that.

## What is energy density and why is it important?

Energy density is a measure of the amount of energy contained within a certain volume or mass of a substance. It is important because it allows us to compare different sources of energy and determine which ones are more efficient and practical to use.

## How do you calculate energy density?

Energy density can be calculated by dividing the total energy of a substance by its volume or mass. The units for energy density are typically expressed in joules per cubic meter or joules per kilogram.

## What are some common units of measurement for energy density?

Common units of measurement for energy density include joules per cubic meter, joules per kilogram, watt-hours per liter, and watt-hours per kilogram. These units can be converted to each other using conversion factors.

## What factors can affect the energy density of a substance?

The energy density of a substance can be affected by its chemical composition, temperature, pressure, and state (solid, liquid, or gas). Additionally, the way in which the energy is stored and released can also impact energy density.

## How is energy density used in practical applications?

Energy density is used in various practical applications, such as determining the efficiency of different types of batteries, comparing the energy output of different fuels, and designing more efficient energy storage systems. It is also used in the development of renewable energy sources, such as solar panels and wind turbines, to optimize their energy production and storage capabilities.

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