Sound is made by vibrations

When an object makes a sound, something is vibrating: moving back and forth very quickly. The vibration transfers sound energy into the surroundings.

Sometimes the vibration is easy to see, such as a ruler wobbling over the edge of a desk. Sometimes it is easier to feel, such as touching your throat gently while you hum.

The action matters because it changes how the object begins to vibrate. The sound-making part—not simply the whole object—should be identified where possible.

Loudness describes how loud or soft a sound seems. Pitch describes how high or low it sounds. These are not the same property.

For a useful investigation, change one feature at a time and keep the rest the same.

Materials can reduce how much sound reaches us. A fair muffling test compares the same sound source using different materials while keeping the distance and sound-making action the same.

An echo is a sound heard again after it reflects from a surface. Humans and other animals can use reflected sound information; the curriculum invites age-appropriate discussion of echolocation, including how some people with vision impairment and animals such as bats and dolphins use returning sound cues to help locate objects.

A simple instrument design should answer three questions:

1. What will vibrate? For example, a string, skin, air column or loose material.
2. What action starts the vibration? Strike, shake, pluck, blow or rub.
3. How can the sound be changed? Change one feature such as tension, length, material or strength of action.

Students should describe both the action and the vibrating part, not only name the instrument.

• “Sound appears without movement.” Look, touch safely or observe indirectly; the sound source is vibrating even if the movement is tiny.
• “Loud means high.” Loud/soft is loudness; high/low is pitch.
• “Blowing is the sound.” Blowing starts vibrations in part of the instrument; the vibration produces the sound.
• Changing several features at once. Change one feature so you can tell what caused the difference.
• “The whole instrument vibrates in exactly the same way.” Identify the main sound-producing part where possible.

• Sound sources vibrate.
• Actions that can start vibrations include striking, shaking, plucking, blowing and rubbing.
• Loudness = loud/soft.
• Pitch = high/low.
• Change one feature at a time when comparing sounds.
• Materials can muffle sound.
• Echoes are reflected sounds heard again.

Mastery check: Explain what vibrates when you pluck an elastic band and how changing the way you pluck it could change the sound.

When exploring traditional musical instruments used by First Nations Australians, use specific, reliable and community-approved sources. Identify the relevant Nation, People or community where known. Avoid treating diverse instruments, practices and cultural meanings as one generic tradition, and follow cultural and intellectual property protocols before reproducing cultural material.

The science question can be framed respectfully: What part of this particular instrument vibrates, and what action produces its characteristic sound?

• E1: build vocabulary for loudness and pitch and compare sounds.
• E2: explore sound-making actions such as striking, blowing, scraping, plucking and shaking.
• E3: explore, in culturally appropriate specific contexts, how First Nations musical instruments produce characteristic sounds.
• E4: explore the unique sounds of voices.
• E5: observe and change ruler vibrations to produce different sounds.
• E6: investigate how sound energy causes vibration using voices, tuning forks or speakers.
• E7: investigate materials that muffle sound.
• E8: design and make simple instruments that produce different sounds.
• E9: discuss echoes and age-appropriate examples of echolocation.