Renewable and Nonrenewable Resources - Second Grade Science
Planet Earth provides us with an abundance of natural resources to build our homes, power our electronics, and grow our food. However, not all resources are replenished at the same rate. Some resources, such as sunlight and blowing wind, are constantly renewed by nature and can never be used up. Other resources, such as underground coal and crude oil, took hundreds of millions of years to form and exist in strictly limited amounts. Understanding the difference between renewable and nonrenewable resources is essential for making wise energy choices for our planet's future.
Renewable Resources: Nature's Endless Supply
A renewable resource is a natural resource that can be replaced, regenerated, or replenished by natural ecological cycles in a short period of time (within a human lifetime) or is completely inexhaustible.
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| RENEWABLE RESOURCES |
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| 1. SOLAR ENERGY Sunlight shines continuously; never runs out! |
| 2. WIND ENERGY Blowing breezes spin massive wind turbines. |
| 3. FRESHWATER Replenished constantly through the water cycle.|
| 4. TREES & TIMBER New saplings grow into mature trees in decades.|
| 5. BIOMASS / CROPS Corn and wheat re-planted and harvested yearly.|
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Inexhaustible Energy: Sun and Wind
Solar energy and wind energy are inexhaustible renewable resources. The Sun will radiate light and heat for billions of years, and the uneven heating of Earth's atmosphere will continuously generate wind. By installing rooftop solar panels and tall wind turbine farms, we generate clean electricity without consuming any fuel or creating air pollution.
Renewable Living Resources: Forests and Crops
Trees, bamboo, and food crops are biological renewable resources. When timber companies harvest pine trees for paper and lumber, they plant new seedlings in their place. In twenty to thirty years, those seedlings grow into a new forest ready for harvest.
Nonrenewable Resources: Limited Treasures
A nonrenewable resource is a natural resource that exists in fixed, limited amounts on Earth and cannot be replaced once it is consumed, because nature takes millions of years to create more.
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| NONRENEWABLE RESOURCES |
| |
| 1. PETROLEUM OIL Crude oil pumped from deep underground rock. |
| 2. COAL Solid black rock formed from ancient swamps. |
| 3. NATURAL GAS Gas trapped in deep shale rock fractures. |
| 4. METALS & MINERALS Iron, copper, gold, and uranium ores. |
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The Fossil Fuel Clock
Fossil fuels (petroleum oil, coal, and natural gas) formed during the Carboniferous Period—over 300 million years ago! When ancient prehistoric trees, ferns, and marine plankton died, they sank to the bottom of swamps and ocean floors. Over millions of years, layers of mud and rock piled on top, exerting crushing pressure and intense geothermal heat that slowly cooked the organic remains into coal, oil, and gas. Because it takes 300 million years to make more, once we pump the last barrel of crude oil out of the ground, it is gone forever!
Metals and Minerals
Metals like copper, aluminum, and gold were formed during cosmic events when planet Earth first formed billions of years ago. There is a finite amount of copper ore in Earth's crust; once mined, we cannot grow more copper!
Comparing Renewable and Nonrenewable Resources
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| RENEWABLE VS. NONRENEWABLE COMPARISON |
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| FEATURE RENEWABLE RESOURCES NONRENEWABLE RESOURCES |
| Supply Inexhaustible or fast-grow Strictly limited finite|
| Replacement Time Days, years, or decades Millions of years! |
| Pollution Level Usually low / clean High greenhouse gases |
| Examples Solar, Wind, Water, Trees Oil, Coal, Gas, Uranium |
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The Global Transition to Green Energy
Because burning fossil fuels produces air pollution and greenhouse gases that warm the planet, and because fossil fuel reserves are gradually being depleted, scientists and engineers around the world are designing electric cars, solar arrays, and hydroelectric dams to power human cities using clean, renewable resources.
Chapter Review Exercises
Question 1: What is the primary difference between a renewable resource and a nonrenewable resource?
Question 2: Why are coal, crude oil, and natural gas classified as nonrenewable fossil fuels?
Question 3: Explain why sunlight and wind are considered inexhaustible renewable energy sources.
Question 4: Can a renewable resource like a forest become depleted if humans are not careful? Explain how.
Solutions and Explanations
Solution 1: A renewable resource can be replenished or regenerated naturally in a short time period (or is inexhaustible like sunlight). A nonrenewable resource exists in limited, fixed amounts and takes millions of years to form, meaning it cannot be replaced once consumed.
Solution 2: Coal, oil, and natural gas are nonrenewable because they formed from the compressed remains of prehistoric plants and organisms buried under extreme heat and pressure over hundreds of millions of years. We are consuming them millions of times faster than nature can ever recreate them.
Solution 3: Sunlight and wind are inexhaustible because using them to generate electricity does not reduce the amount of sunlight or wind available tomorrow. The Sun will continue shining and wind will continue blowing naturally regardless of how many solar panels or wind turbines we install.
Solution 4: Yes, a forest can become depleted if trees are clear-cut faster than new seedlings are planted and allowed to grow to maturity, or if soil erosion damages the land so trees can no longer grow. Renewable resources must be managed responsibly through sustainable conservation practices.