LIGHT AND SOUND (6º)

LIGHT:

Form of energy that makes us see.

Light speed: 300,000 km/sec

It always travels in a straight line, in all directions.

                    LIGHT ==========ètttttttttttttttuuuuuu

If an object blocks the light, a shadow is formed:

LIGHT ==========èshadow

TRANSPARENT OBJECTS OR SUBSTANCES: glass, air… allow light to pass

TRANSLUCENT OBJECTS: paper, plastic, water… allow just some light to pass

OPAQUE OBJECTS: a book, a door… don´t let the light pass

REFLECTION:

When the light hits an object it is REFLECTED and changes its direction. We can see the Moon because the light of the sun is reflected in its surface.

REFLECTION OF THE LIGHT: same angle in opposite direction

COLORS:

We usually see the light white, but it is actually made up of millions of colors.

The rainbow is formed by the 7 primary colors: red, orange, yellow, green, blue, indigo, violet.

                                     The seven primary colours

The color of an object is the color of the light which the object reflects: a red bag absorbs all the colors of light except red, and reflects red light into our eyes.

REFRACTION:

The light passes through a transparent object or medium and it BENDS and CHANGES direction is called REFRACTION.

REFRACTION OF LIGHT: the light bends and changes direction

SOUND

Is a form of mechanical energy produced by the vibration of an object.

sound travels in waves through solids, liquids and gases.

SPEED OF SOUND: 340 metres per second.

REFLECTION OF SOUND:

Echo: is the reflection of sound. When echo is repeated it is called reverberation.

QUALITIES OF SOUND:

Intensity: depends on the amplitude of the sound

LOUD SOUND: large amplitude

SOFT SOUND: small amplitude

Pitch: the frequency of the sound waves

HIGH sound

LOW sound

Tone: to identify the source of the sound