Science Fenns K-5Grades K to 5
A pond with ripples spreading from a dropped pebble and a guitar string vibrating beside it.

Science / All lessons / Energy on the Move

Sound and Water Waves

Energy that travels without carrying the water or the air.

Lesson 18 of 40

Try this first

Before we start

Today’s story

Sound and Water Waves

Dee drops a pebble in the stock tank and watches rings spread out. A leaf on the water bobs up and down. It does not float to the edge with the ripples. The wave moves. The leaf mostly stays.

Waves carry energy from one place to another without carrying the water along. Sound is a wave too. When a drum is hit, it shakes. The shaking pushes on the air. The air passes it along. Your ear gets the shaking and you hear a sound.

Sound needs something to travel through, like air, water or a wall. It cannot travel through empty space. Bigger waves carry more energy. A loud sound has a big wave. Here are the steps.

See it

Five steps. Every time.

    Hands on

    Ripples and Rubber Band Sounds

    25 minutes · Do this with a grown-up nearby

    You need

    • A shallow pan of water
    • A small cork or a leaf
    • An eyedropper or a pebble
    • A rubber band
    • An empty box or tub
    • Notebook

    Do this

    1. Fill the pan and let the water settle.
    2. Place the cork near the middle.
    3. Drop one drop of water near the edge and watch the ripples.
    4. Drop from higher up and compare ripple size.
    5. Stretch a rubber band across the box and pluck it softly.
    6. Pluck it harder and listen.
    7. Touch the band lightly and feel it shake.
    Write or draw: A drawing of the ripples and a table of Soft or Hard pluck, what you heard.

    Watch for: Notice that the cork bobs and stays. Notice that a harder pluck made a louder sound.

    Safety: Keep water on the table and not near outlets, and do not pull the band toward your face.

    Same every time

    Three rules

    Rule 1A wave carries energy.

    It does not carry the water.

    Rule 2Sound is a vibration.

    Shaking air carries it.

    Rule 3Bigger waves have more energy.

    Loud sounds are bigger waves.

    Grandpa Fenn’s notebook

    Say it like a scientist

    wave
    A way energy travels from place to place.
    vibration
    A fast back and forth shaking.
    sound
    Energy from vibrations that you can hear.
    ripple
    A small wave on 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 wave moves energy but not water?
    • When have you felt sound, such as a loud speaker or thunder, shake something?
    Did you know

    Sound travels about four times faster in water than in air.

    Someone who does this

    A sound engineer sets up speakers so everyone can hear.

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