1. Marcos Sánchez Herrero, 6ºB
Abril 2013

2. What is light?
• Light is a form or energy.
• We can see objects because they reflect light.
• Light can be: natural or artificial.
How does light travel?
o Light travels in straight lines and in
all directions from the source of light.
o Light travels at 300.000 km/sc.

3. The effect of light of materials.
Light passes Only part of the light passes Light does not pass

4. The properties of light.
 Reflection.
Reflection lets us see objects that do not emit light.
 Refraction.
- When a ray of light goes from air to water,
its speed changes and its path.
- Light reflects when it passes through a lens.
- Lenses can be converging an diverging.
Diverging lenses make rays separate. Converging lenses make rays come together.

5. The uses of lenses.
Glasses and contact lenses. Projectors.
Telescopes and binoculars. Magnifying glasses and microscopes.

6. What is sound?
Sound is a form of energy produced by vibrations.
The characteristics of sound
1. Intensity: Sounds can be soft or loud.
2. Pitch: Can be high or low.
3. Timbre: Is the quality of a sound.
How does sound travel?
Sound travels in all directions and in a straight line.
Sound is slower than light. It travels at 340 m/sc.

7. Echo and reverberation.
Sound travels in waves. When the sound waves reach an obstacles, they
reflect in two different ways:
1. Echo happens when the obstacle is more than 17 metres away. We hear
a different in time between the sound and its reflection.
2. Reverberation happens when the obstacle is a shorter distance away.
The reflected sound mixes with the emitted sound.