Science Fenns K-5Grades K to 5
A cross-section of layered rock under a Texas field showing a pump above an oil layer and a well reaching water.

Science / All lessons / Energy and Earth Resources

Rocks That Store Resources

Pores, gaps and the oil and water in them.

Lesson 33 of 40

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Before we start

Today’s story

Rocks That Store Resources

Think of a bucket of sand and a bucket of marbles. Pour water in. Water fills the spaces between the sand grains.

Rocks can have tiny gaps called pores. Sandstone and limestone often do. Oil, natural gas and water can fill those pores deep underground.

Other rocks, like shale, have few connected pores. They block the flow. Together these rocks trap the resource. Follow the steps.

See it

Five steps. Every time.

    Hands on

    Which Holds More?

    25 minutes · Do this with a grown-up nearby

    You need

    • Sand
    • Gravel
    • Clay soil from outside
    • Three clear cups
    • Measuring cup
    • Water
    • Paper towels

    Do this

    1. Fill each cup to the same line with one material.
    2. Measure a cup of water.
    3. Pour slowly into the first cup until the water reaches the top of the material.
    4. Record how much water it took.
    5. Repeat with the other two.
    6. Compare the amounts.
    7. Rank them from most to least.
    Write or draw: A table with the amount of water each material held.

    Watch for: Gravel and sand hold water and let it move. Clay soil holds some but lets little through.

    Safety: Keep spills off the floor and wash hands after clay.

    Same every time

    Three rules

    Rule 1More pores store more.

    Gaps are the storage.

    Rule 2Connected pores let fluid move.

    Wells reach the fluid that flows.

    Rule 3Tight rock traps.

    It acts like a lid.

    Grandpa Fenn’s notebook

    Say it like a scientist

    pore
    A tiny gap in a rock.
    porous
    Having many pores.
    permeable
    Letting fluids pass through.
    reservoir
    A rock layer that holds oil, gas or water.

    Poppy’s quiz

    Six questions

    Tap an answer. Green means right. You will see why.

    Talk about it

    Say it out loud

    • How do you know a rock is porous?
    • Where might water be stored under your town?
    Did you know

    The Ogallala Aquifer under the Texas Panhandle stores water in sand and gravel.

    Someone who does this

    A hydrogeologist finds underground water.