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Chapter 5
Earth’s Resources
Lesson 1
Minerals and Rocks
Mineral- a solid, natural material made from nonliving substances in the ground
Minerals are made from elements and are found in nature.
Properties of Minerals:
Luster – the way a mineral reflects light from its surface. (metallic or waxy)
Hardness – the measure of how well a mineral resists scratching. A hard mineral resists
scratching better than a soft mineral.
Cleavage – when the surfaces are smooth
Fracture – when a mineral has rough or uneven surfaces
Minerals form crystals that can be different shapes and sizes.
Gems are minerals that are rare, beautiful, usually transparent, and shine in the light.
The Rock Cycle
Rocks are solid objects made naturally in Earth’s crust and contain one or more minerals. Most
rocks are made of mixtures of materials because they are made differently.
Types of Rocks:
1. Sedimentary rock – rock that forms from sediment that is compacted together
 Almost all fossils are found in sedimentary rock
 Sedimentary rock often used in buildings
 Limestone, sandstone, and conglomerate
2. Igneous rock – rock formed from lava that cools and hardens
 Intrusive: igneous rock formed inside the Earth (granite)
 Extrusive: igneous rock formed outside Earth (obsidian)
3. Metamorphic rock – rock formed from sedimentary and igneous rocks that are changed
under heat and pressure without melting
 Heat and pressure can change one mineral into another
 marble
Rocks change from one type to another over time in a process called the rock cycle.
Lesson 2
Soil
Soil is a mixture of bits of rock and once-living parts of plants and animals.
There are layers of soil called horizons.
Horizon A:
 Topsoil
 Holds most nutrients
 Humus – soil that is made of decaying organic material.
Horizon B:
 Subsoil
 Has little bits of rocks
Horizon C:
 Mostly larger pieces of weathered rock
Forests have thin layers of topsoil and rain washes minerals deep into the ground. Plants with
long roots can grow, but crops with shallow roots cannot.
Deserts have sandy soil and little rain which holds minerals.
Grasslands have soil rich in humus so crops and other plants can grow well.
Soil is a resource that can be used up. Plants remove nutrients from the soil as they grow, but
when they die and decay, they replace the nutrients.
Soil can also be polluted by chemicals.
How do we conserve the soil?
A. Fertilization – add nutrient
B. Crop rotation – alternate the type of crops planted from year to year
C. Strip farming – plant grass between rows of crops to prevents soil from washing away
D. Contour plowing
E. Terracing – planting crops in flat shelves cut into the hillside
F. Wind breaks – plant tall trees along the edge of farmland to block the wind
G. Pass laws
H. Individual efforts
I. Education
Lesson 3
Natural Resources
Fossil fuels are formed from the remains of plants and animals that died many years ago.
Organisms died and were buried deep underground. Heat and pressure turned them into oil
and natural gas.
When fossil fuels are burned, they release the energy the plants stored. We can turn the energy
released into other forms of energy.
Fossil fuels can power cars, heat buildings, and generate electricity.
Types of natural resources:
 Nonrenewable – one that can be used up faster than it is made
Fossil fuels are nonrenewable. Once they are used up, they cannot be replaced in our
lifetime.
 Renewable – nature can replace these resources relatively quickly.
Wind, water power, and sunlight are nonliving renewable resources.
Fish, plants, and animal waste come from living things and are renewable.
We must protect our living renewable resources. (Replant trees; keep from over fishing)
Freshwater
97% of water on earth is salt water. 2.3 % of freshwater is frozen at the North and South Poles.
0.1% is in the atmosphere as water vapor. How much drinkable water is left?
Where does the salt in the salt water come from? Water runs downhill and picks up salts from
the soil and rocks and flows into rivers and then into oceans. Over millions of years, the salt in
the ocean adds up.
Running water provides water homes, farms, and businesses.
Reservoirs are artificial lakes built to store water. They are made by a dam on a river.
Ground water can also seep through rock with pores. (aquifer)
How can we drink this water?
Water that reaches our house has been treated, or cleaned. Sticky particles are added to attract
dirt so it can be removed. Water then goes through filters of sand, gravel ad charcoal.
Chemicals are then added to kill bacteria.
Lesson 4 Conservation
How do we pollute air and water?
Smog is air pollution that is caused by the burning of fossil fuels.
Pollution can destroy the ozone.
The ozone is a form of oxygen that protects living things on Earth from the Sun’s
dangerous radiation.
When chemicals are dumped from factories and homes, the chemicals can reach
sources of water and pollute them.
How does Mississippi conserve natural resources?
The Healthy Forests Reserve Program protects wildlife habitats and endangered
species.
Mississippi has tree farms to grow and harvest trees so forest ecosystems are not
destroyed.
Mississippi grows corn to turn into ethanol to use instead of gas.
Mississippi has fish farms to repopulate the fish.
Alternative Energy Sources
An alternative energy source is any source of energy other than fossil fuels.
Some alternative energy sources include wind, moving water, and solar (sun)
energy.
What are some positive and negative points about each of these?
Geothermal energy is heat produced inside earth. This heat can power machines.
Nuclear energy comes from atoms that change from one element into another
and put off great amounts of heat
How can you conserve energy at home and at school?
The 3 Rs: Reduce the amount of products we use
Reuse the materials we might throw away
Recycle by taking materials to places where they can be made
into something else.