Download to read offline
Uploaded byDIAH KOHLER
Light and Shadow
Light is a form of energy that travels in straight lines and allows us to see objects. It can behave as both a particle and a wave. Light sources like the sun emit light, while other objects appear visible when light reflects off of their surfaces. Light can be transmitted through transparent materials, scattered through translucent materials, or blocked by opaque materials. When light hits an object, it can be reflected, absorbed, or transmitted. Shadows are formed when an object blocks light from a source, and their size depends on the distance between the object and light source. Light plays an important role in vision, photosynthesis, and warming the Earth.
More Related Content
More from DIAH KOHLER
Light and Shadow
- 1. TOPIC 3 LIGHTAND SHADOW BY Ms Diah P5
- 2. Today we arelearning ? • what is light ? • How does light travel ? • Porperties of light • Transparent and opaque objects • What is a shadow ? • Properties of shadow • Importance of shadow
- 3. What is lightmade of? • This is not an easy question. Light has no mass and is not really considered matter. • So does it even exist? Of course it does! • We couldn't live without light. Today scientists say light is a form of energy made of photons. Light is unique in that it behaves like both a particle and a wave.
- 4. what is light? • You may see the light from the sun , natural source of light. Light is a form of energy • We are to see light from candle, bulb, tube light (artificial sources of light)
- 5. We can seelight when : • An object gives off its own light (like a sun) • An object reflects light into our eyes • Objects that give off light are called sources of light
- 6. LIGHT SOURCES • Asource of LIGHT make light. THE SUN and other stars, fires, torches, and lamps all make their own light and so are examples of SOURCES OF LIGHT • Some animal, such as FIREFLIES and GLOW- WORMS, are light sources. They make their own light to attract mates.
- 7. Fill in thegaps using the words : source – straight – starts - universe • Something that produces its own light is known as a ............ Of light. • Fire, lamps and ......are all examples. • Light travels is ....... Lines and is the fastest thing in the .......
- 8. Why does lightgo through some things and not others? • Depending on the type of matter it comes into contact with, light will behave differently. • Sometimes light will pass directly through the matter, like with air or water. • This type of matter is called transparent. • Other objects completely reflect light, like an animal or a book. These objects are called opaque. • A third type of object does some of both and tends to scatter the light. These objects are called translucent objects.
- 9. What are theProperties of Light? • Following are the important properties of light – • Light travels in a straight line. • The speed of light is faster than sound. Light travels at a speed of 3 x 108 m/s.
- 10. Can we seethrough ALL objects ? • WE can see lights can pass though GLASS
- 11. BUT WHAT ABOUTTHIS ? • WELL we cannot see clearly frosted glass. • Because light is partially blocked
- 12. • We cannotsee light because is completely blocked
- 13. How does lighttravel ? • Light travel in the street line in the air • This line are called rays • Light travel in wave • Light moves at the fastest known speed in the universe. Nothing moves faster than (or even close to) the speed of light. In a vacuum, where there is nothing to slow it down, light travels 186,282 miles per second! Wow, that's fast! When light travels through matter, like air or water, it slows down some, but it's still pretty fast. To give you an idea as to how fast light is, we'll give you some examples. The Sun is almost 93 million miles from the Earth. It takes around 8 minutes for light to get from the Sun to the Earth. It takes around 1.3 seconds for light to go from the moon to the Earth.
- 15. What is Reflection •Reflection (when light from an object is reflected by a surface, it changes direction. It bounces off surface at the same angle as it hits it. Smooth, shiny surface such a mirror and polished metals reflect light well. Dull and dark surfaces such as dark fabrics do not reflect light well
- 16. When light hitsan object, its transmitted, absorbed, and/or reflected The light on the left is reflected, the light in the middle is absorbed and the light on the right is transmitted. Any object you can see must at least partially reflect light to your eyes. Objects can ALSO absorb and/or transmit light.
- 17. Transmitted Light 1. Transmitted– light that passes through a substance a.Transparent – visible light is transmitted easily and objects are seen clearly b.Translucent – some visible light is transmitted, but some is scattered (or diffused) so that objects are not clearly seen
- 18. Law of Reflection "Normal"is the imaginary line that is perpendicular to the object. Whether a surface is smooth or bumpy, light ALWAYS obeys the Law of Reflection
- 19. The blue incidentlight rays scatter in different directions (red rays) off a rough surface, but STILL obey the Law of Reflection
- 20. Absorbed Light Absorbed –light energy hitting the surface is converted to heat energy a. Dark or black objects absorb more light and feel hotter than lighter or white objects b. Objects that do not transmit or reflect much visible light, absorb it, so the object appears opaque (you can't see through it)
- 21. How Light Reflects •When light reflects off a surface, the angle of incidence (incoming light) is equal to the angle of reflection (outgoing light) – called “Law of Reflection” • i. If you shine a narrow beam at a highly polished surface (like a mirror), you get a narrow beam of light reflected back off it (called specular reflection) • ii. If you shine a narrow beam of light at a rough surface, the light scatters in all directions, (called diffuse reflection) but still obeys Law of Reflection
- 22. Compare light thatreflects off a smooth and rough surface When light reflects off a surface, it obeys the Law of Reflection (the angle of incidence is equal to the angle of reflection), whether or not the surface is smooth. The light is reflecting off the flower to the water and then back to your eye.
- 23. Compare light thatreflects off a smooth and rough surface In the wavy water, the some of the light is scattered so you do not see a perfect reflection. If the water was even more disturbed - for example, stormy and very wavy - you might not see the reflection at all because the light is even more scattered so that it does not reach your eyes.
- 24. When light hitssomething and bounces off it we say it reflects Light is what helps us to see we objects only when light reflects off them when its dark and no light is reflecting we cannot see anything
- 25. • A mirroris very shiny thats why its reflects so much light and we see ourselves in it materials that are dull do not reflect a lot of light
- 26. • When lighttravels through water , glass, plastic or any other thick substance it slow down.
- 27. 1. A pieceofplastic wrap 2. A piece of waxed paper 3. A piece of aluminium foil..
- 28. Let us nowsee what our TRANSPARENT, TRANSLUCENT, and, OPAQUE Objects we can observe objects to find out how much light passes through them. A piece of plastic wrap, a piece of waxed paper, a piece of aluminium foil.. If you held them up to the light to how much light shone through them 1. So the light would pass directly through the plastic wrap light passes easily through clear objects like glass and clear plastic we call these objects TRANSPARENT 2. The light would somewhat shine through the wax paper but not completely. Few objects like stained glass windows and thinly colored plastic let SOME LIGHT THROUGH, but not all. They are TRANSLUCENT 3. The light in the aluminium foil , no light passes. We call objects that BLOCK ALL LIGHT OPAQUE
- 29. • When lighthits an opaque object it is stopped in its tracks it cannot pass behind the object that blocks the light you will see a SHADOW
- 30. What is ashadow ? • How are shadows formed ? • A shadow is formed when an OBJECT BLOCKS THE LIGHT
- 31. Size of SHADOWS •It changes with the distance between the object and the light source: • If we move the light CLOSER to the object, the shadow is BIGGER
- 32. CAN YOU SEEIT ? • If we move the light FURTHER from the object , the shadow is SMALLER
- 33. Light helps usto survive • Without sunlight our world would be a dead dark place. • Sunlight does more than just help us see (which is pretty great, too). • Sunlight keeps the Earth warm, so it's not just a frozen ball in outer space. • It also is a major component in photosynthesis which is how most of the plant life on Earth grows and gets nutrients. • Sunlight is a source of energy as well as a source of vitamin D for humans.