Sound and Light Chapter 17. Lesson 1: What is Sound? Lesson 2: What is Light?. Lesson One Vocabulary. Vibration- a back-n-forth movement of matter Volume- the loudness of a sound Pitch- how high or low a sound is Frequency- the number of vibrations per second. Lesson 1: Sound.
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Lesson 1: What is Sound?
Lesson 2: What is Light?
Volume is measured in decibels (dB).
A high decibel sound is loud and has a lot of energy.Lesson 1: Sound
Some sounds are high while other sounds are low.
A sound’s pitch is how high or low the sound is.
The number of vibrations in a second is the frequency of a sound.
Frequency and pitch are related.
A sound with high frequency has a high pitch and a low pitch has a low frequency.Lesson 1: Sound
hard surface bounces
back and it called an
echoes in caves
but the particles stay in the
Matter that carries sound is called a medium.
Sound waves need a medium to travel.
The speed of sound depends on the medium.
Sound travels fastest in solids and slowest in gases.
Sound also moves faster when it’s warm that when it’s cold.Lesson 1: Sound
Dogs can hear high pitched sounds.
Bats have excellent hearing and when they fly they produce sound which bounces off objects.
The bat can hear its echoes and this allows the bat to fly in the dark. Cool!Lesson 1: Sound
we can see is called
the spectrum have different
Light waves move like ocean waves because they move up and down.
Light waves can travel through matter or through empty space.
Light moves thousands of times faster than sound.
It only takes 8 minutes for light travel from the sun to Earth.Lesson 2: Light
You can also feel the heat from a light bulb.
The sun and the light bulb both send out light in all directions.
But a laser gives off light in a narrow beam which is very powerful because the waves are close together.Lesson 2: Light
Reflection occurs when light bounces off a surface.
In most cases, light spreads out when it is reflected.
But a smooth surface does not spread out and this is why you can see yourself in a mirror.Lesson 2: Light
Opaque materials do not let any light pass through them.
You cannot see through opaque objects.
Most objects around you are opaque, like you shoes, your desk, and a book.Lesson 2: Light
Transparent materials let light pass through. Most kinds of glass are transparent.
Translucent materials only let some light pass through.
Stain glass windows are translucent.
The difference between transparent and translucent is how they spread out light.
Translucent materials spread more light.Lesson 2: Light
This bending is called refraction.
Refraction changes the angle at which you see things.
Have you ever looked at a straw in a glass of water?
It seems to bend where the straw enters the water. This is refraction.Lesson 2: Light
A convex lens is thicker at the center that it is at the edges.
It bends light waves to bring them together.
A convex lens makes images bigger.Lesson 2: Light