Science Fenns K-5Grades K to 5
Four small devices side by side powered by a battery: a lit bulb, a spinning motor, a buzzer and a warm wire.

Science / All lessons / Energy, Circuits and Light

Circuit Outputs

Motion, light, sound and heat from electricity.

Lesson 20 of 41

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Before we start

Today’s story

Circuit Outputs

Flip a switch and a lot can happen. A lamp glows. A fan spins. A buzzer sounds. A heater warms.

Electric energy in a complete circuit can become light, motion, sound or heat. The load decides which one.

Today we match each load to its output. We build circuits and see what each load gives back. Here are the steps.

See it

Five steps. Every time.

    Hands on

    Output Tester

    25 minutes · Do this with a grown-up nearby

    You need

    • Battery
    • Wires
    • Small bulb
    • Small motor
    • Buzzer
    • Paper
    • Pencil

    Do this

    1. Connect the bulb and note the output.
    2. Swap the bulb for the motor.
    3. Swap in the buzzer.
    4. Touch the bulb after a minute to check warmth.
    5. Record each output.
    6. Add a switch to each circuit.
    Write or draw: A table with the load and its output form.

    Watch for: Which loads made more than one output?

    Safety: Use only small batteries and let parts cool.

    Same every time

    Three rules

    Rule 1The load picks the output

    Each device is built for a job.

    Rule 2Heat is often a side effect

    Many devices warm up as they work.

    Rule 3A circuit must be closed

    No loop, no output.

    Grandpa Fenn’s notebook

    Say it like a scientist

    output
    What a device gives out, such as light.
    motor
    A device that turns electrical energy into motion.
    buzzer
    A device that turns electrical energy into sound.
    resistance
    A property that slows current and makes heat.

    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 electric energy changed form?
    • What outputs do you see in your home?
    Did you know

    A modern LED bulb makes far less heat than an old filament bulb for the same light.

    Someone who does this

    A technician fixes appliances by checking their circuits and loads.

    BeforeWhat a Circuit NeedsNext lessonLight Travels Straight