Sound

What is sound energy?

• Energy produced by vibrations

• Energy produced by light

• Energy produced by heat

• Energy produced by electricity

Answer explanation

Sound energy is the energy produced by vibrations. When objects vibrate, they create sound waves that travel through a medium, making this the correct choice. Other options relate to different forms of energy.

Vibrations (sound waves) are what cause sound to happen.

• true

• false

Answer explanation

True. Vibrations, or sound waves, are the physical phenomenon that produce sound. When objects vibrate, they create pressure waves in the air, which we perceive as sound.

What is a sound wave?

• A transfer of energy that travels away from the vibrating source

• A type of light wave

• A solid object

• A type of gas

Answer explanation

A sound wave is a transfer of energy that travels away from a vibrating source, creating pressure variations in a medium, unlike light waves, solids, or gases.

What is necessary for sound waves to be heard?

• A vacuum

• A medium (substance) like air, water, or metal

• Complete silence

• Darkness

Answer explanation

Sound waves require a medium, such as air, water, or metal, to travel through. In a vacuum, there are no particles to transmit the sound, making it impossible to hear. Therefore, a medium is necessary for sound to be heard.

Match the picture of the sound waves to the proper description.

• Quiet sound

• 
• Loud sound

• 
• Low/deep sound

• 
• High sound

• 

What can cause sound besides your voice?

• Moving your chair

• Waving your hands

• Smiling at your friend

• Reading a book

Answer explanation

Moving your chair can create sound due to friction and movement against the floor, while waving your hands, smiling, or reading a book typically do not produce sound.

What is the effect of extra energy from vocal cords?

• Smaller sound waves

• Larger sound waves

• No sound waves

• Light waves

Answer explanation

Extra energy from vocal cords increases the amplitude of sound waves, resulting in larger sound waves. This is why the correct answer is 'Larger sound waves'.

Why can't you hear sound in outer space?

• Because there are no particles

• Because it's too loud

• Because it's too quiet

• Because it's too bright

Answer explanation

Sound requires a medium, like air or water, to travel through. In outer space, there are very few particles, making it impossible for sound waves to propagate. Thus, you can't hear sound in outer space.

What is needed for vibrations to travel?

• A medium

• A vacuum

• A light source

• A magnet

Answer explanation

Vibrations require a medium, such as air, water, or solids, to travel through. Unlike light, which can move through a vacuum, sound waves need a medium to propagate, making 'A medium' the correct choice.

What happens to particles in a medium when sound waves move through it?

• They vibrate forwards and backwards

• They stop moving

• They change color

• They disappear

Answer explanation

When sound waves travel through a medium, they cause the particles to vibrate forwards and backwards. This vibration allows the sound energy to propagate through the medium, making 'They vibrate forwards and backwards' the correct choice.