Luminous, non-luminuos, how do we see things

Ray model of Light Luminous and non-luminous, How we see t hings Teacher: Đặng Thái Nhật Sour ces of Light ? Are the following pictures all sources of light? I f not, why and where does the light come from? AND is it natural or artificial Natural light: Ánh sáng tự nhiên Artificia l light: Ánh sá ng nhâ n tạo Photo courtesy of Bonsoni.com(@flickr.com) - granted under creative commons licence – attribution Photo courtesy of Andrew Kuchling(@flickr.com) - granted under creative commons licence – attribution Tor ch Photo courtesy of mjtmail (tiggy) (@flickr.com) - granted under creative commons licence – attribution Can you t hink of any ot her s? Fun Fact ! Some creatures are natural sources of light Jellyfish Fir efly Glow-wor m Nat ur al Ar t ificial Light that nature makes Light we cannot turn on and off Light that people make We can turn these lights on and off What is Light sour ce? A light source (or Luminous object) is anything that makes light, whether natural and artificial Object: vật thể Natural light: Ánh sáng tự nhiên Artificial light: Ánh sáng nhân tạo Non Luminous object s: - Do not emit their own light - Examples: Moon, Mirror, Pencils, a dog, … Luminous object s: - Emit their own light - Examples: Sun, Fire, Firefly, torch, candle, lightning, … Torch: đèn Object: vật thể Firefly: đom đóm Lightning: tia chớp How we see object s? Because of Light How Does Light Help Us See? Rays of light travel from a light source and hit objects around us The rays of light reflect, off an object, and then travel into our eyes This reflection of light allows us to see the object Reflect: dội lại, phản xạ lại Light from the light bulb travels in a straight line and hits the chair The ray of light is reflected off the chair and travels in a straight line to the girl’s eyes, enabling her to see the chair Can you describe how you can see some objects right now? Summar y: Light source (or Luminous objects): are anything that can emit their own light Non – luminous objects: are anything that cannot emit their own light Light travels in straight line We see things because Light hits to the objects then reflected to our eyes ... … Torch: đèn Object: vật thể Firefly: đom đóm Lightning: tia chớp How we see object s? Because of Light How Does Light Help Us See? Rays of light travel from a light source and hit objects around... the chair and travels in a straight line to the girl’s eyes, enabling her to see the chair Can you describe how you can see some objects right now? Summar y: Light source (or Luminous objects):... luminous objects: are anything that cannot emit their own light Light travels in straight line We see things because Light hits to the objects then reflected to our eyes