Placemat Activity: Different Types of Light
description
Transcript of Placemat Activity: Different Types of Light
![Page 1: Placemat Activity: Different Types of Light](https://reader036.fdocuments.us/reader036/viewer/2022062521/568166d6550346895ddaed1b/html5/thumbnails/1.jpg)
![Page 2: Placemat Activity: Different Types of Light](https://reader036.fdocuments.us/reader036/viewer/2022062521/568166d6550346895ddaed1b/html5/thumbnails/2.jpg)
![Page 3: Placemat Activity: Different Types of Light](https://reader036.fdocuments.us/reader036/viewer/2022062521/568166d6550346895ddaed1b/html5/thumbnails/3.jpg)
Placemat Activity: Different Types of Light
![Page 4: Placemat Activity: Different Types of Light](https://reader036.fdocuments.us/reader036/viewer/2022062521/568166d6550346895ddaed1b/html5/thumbnails/4.jpg)
Unit 4: Chapter 10 – Sources and Nature of Light (p.403-410)
Artificial • Genetically modified zebrafish
emit visible light when exposed to UV radiation.
Natural• Algae and bacteria are able to
emit light naturally – Bioluminescence
![Page 5: Placemat Activity: Different Types of Light](https://reader036.fdocuments.us/reader036/viewer/2022062521/568166d6550346895ddaed1b/html5/thumbnails/5.jpg)
Bioluminescence
![Page 6: Placemat Activity: Different Types of Light](https://reader036.fdocuments.us/reader036/viewer/2022062521/568166d6550346895ddaed1b/html5/thumbnails/6.jpg)
What is light? • Light is a form of energy known as electromagnetic
waves
– When energy is absorbed electrons move to an excited state.
– These excited electrons release energy in the form of light.
• In other words, the light that is seen is the light that is emitted, NOT ABSORBED
– E.g. Chlorophyll is green because it does not absorb green light
![Page 7: Placemat Activity: Different Types of Light](https://reader036.fdocuments.us/reader036/viewer/2022062521/568166d6550346895ddaed1b/html5/thumbnails/7.jpg)
Types of Light Emissions• There are three types of light emissions:
– Light from the sun
– Light from incandescent
– Light from electric discharge
![Page 8: Placemat Activity: Different Types of Light](https://reader036.fdocuments.us/reader036/viewer/2022062521/568166d6550346895ddaed1b/html5/thumbnails/8.jpg)
Sun light• Hydrogen atoms in the Sun’s core are moving
at rapid speeds and colliding with one another
• These collisions will sometimes cause two Hydrogen's to fuse together forming Helium.– A fusion reaction
• This reaction releases a ton of energy creating light.
![Page 9: Placemat Activity: Different Types of Light](https://reader036.fdocuments.us/reader036/viewer/2022062521/568166d6550346895ddaed1b/html5/thumbnails/9.jpg)
Sunlight• Sunlight emits white light which is made up of
all light colours.
![Page 10: Placemat Activity: Different Types of Light](https://reader036.fdocuments.us/reader036/viewer/2022062521/568166d6550346895ddaed1b/html5/thumbnails/10.jpg)
Incandescent Light
• Incandescent light occurs when a metal is heated to produce light– Tungsten wire is typically used because of its
brightness when heated
• It is inefficient at producing light since only 5% of the heat used produces light.– The other 95% is lost as heat
![Page 11: Placemat Activity: Different Types of Light](https://reader036.fdocuments.us/reader036/viewer/2022062521/568166d6550346895ddaed1b/html5/thumbnails/11.jpg)
Incandescent Demonstration Copper Penny
• Why might an older penny (1962- 1982) be more effective at producing light when heated?
![Page 12: Placemat Activity: Different Types of Light](https://reader036.fdocuments.us/reader036/viewer/2022062521/568166d6550346895ddaed1b/html5/thumbnails/12.jpg)
Electric Discharge Light• Electric discharge light is produced when an
electric current passes through a gas source• The electrons within the gas become excited causing them
to release light.
• Various gases emit different light sources
![Page 13: Placemat Activity: Different Types of Light](https://reader036.fdocuments.us/reader036/viewer/2022062521/568166d6550346895ddaed1b/html5/thumbnails/13.jpg)
Where might you see various gases being used
to produce light?
Christmas lightsSigns
Traffic lights Fireworks
![Page 14: Placemat Activity: Different Types of Light](https://reader036.fdocuments.us/reader036/viewer/2022062521/568166d6550346895ddaed1b/html5/thumbnails/14.jpg)
Fluorescent Light• Fluorescent lights are commonly found in school,
businesses, and various other industries.
• Fluorescent lights are composed of a phosphor powder coating, mercury, and a noble gas.
• At each end of a fluorescent light there is an electrode.
![Page 15: Placemat Activity: Different Types of Light](https://reader036.fdocuments.us/reader036/viewer/2022062521/568166d6550346895ddaed1b/html5/thumbnails/15.jpg)
Fluorescent Light (Fig 10.5) • When an electric current is applied to a fluorescent
light bulb, electrons collide with mercury atoms.
• The mercury will then release UV radiation (not visible) which is absorbed by the phosphor coating
– The phosphor coating emits visible fluorescent light
![Page 16: Placemat Activity: Different Types of Light](https://reader036.fdocuments.us/reader036/viewer/2022062521/568166d6550346895ddaed1b/html5/thumbnails/16.jpg)
Demonstration: Blacklight Applications
• Ask students for cash money, tell them thank you, I have just demonstrated how easy it is to get people to give you money.
![Page 17: Placemat Activity: Different Types of Light](https://reader036.fdocuments.us/reader036/viewer/2022062521/568166d6550346895ddaed1b/html5/thumbnails/17.jpg)
Literacy Check: Fluorescent Applications
• In the same group as the placemat, read page 406 (Figure 10.7)
• Create a short scenario (4-5 sentences) where fluorescence may be used. Explain how fluorescence helped resolve the problem.
![Page 18: Placemat Activity: Different Types of Light](https://reader036.fdocuments.us/reader036/viewer/2022062521/568166d6550346895ddaed1b/html5/thumbnails/18.jpg)
Types of Luminescence• Luminescence:– Is the light produced without heating an object
– Fluorescence is a type of luminescence because it does not use heat to produce light
– Phosphorescence, chemiluminesence, and bioluminescence are all prime examples of luminescence.
![Page 19: Placemat Activity: Different Types of Light](https://reader036.fdocuments.us/reader036/viewer/2022062521/568166d6550346895ddaed1b/html5/thumbnails/19.jpg)
1. Phosphorescence• Phosphorescence:– Is similar to fluorescent light because it uses UV
light to create light
– However, the major difference is that phosphorescence glows long after the UV light has been absorbed
![Page 20: Placemat Activity: Different Types of Light](https://reader036.fdocuments.us/reader036/viewer/2022062521/568166d6550346895ddaed1b/html5/thumbnails/20.jpg)
2. Chemiluminescene• Chemiluminescence is light that is generated
by the energy released in a chemical reaction.
![Page 21: Placemat Activity: Different Types of Light](https://reader036.fdocuments.us/reader036/viewer/2022062521/568166d6550346895ddaed1b/html5/thumbnails/21.jpg)
3. Bioluminescence• Bioluminescence is a form of chemiluminescence– Occurs where energy is released by a chemical
reaction in the form of light.
![Page 22: Placemat Activity: Different Types of Light](https://reader036.fdocuments.us/reader036/viewer/2022062521/568166d6550346895ddaed1b/html5/thumbnails/22.jpg)
Homework• Answers questions #1-4 (p. 407)• Notes: Question number one discuss the
“excited atom”. In this lesson we have focused on the “excited electron” which is part of the atom.
![Page 23: Placemat Activity: Different Types of Light](https://reader036.fdocuments.us/reader036/viewer/2022062521/568166d6550346895ddaed1b/html5/thumbnails/23.jpg)
The Nature of Light• Light is energy that travels like a wave through
empty space. – Electromagnetic waves
• Electromagnetic waves function as ocean waves as they have a crest and a trough
![Page 24: Placemat Activity: Different Types of Light](https://reader036.fdocuments.us/reader036/viewer/2022062521/568166d6550346895ddaed1b/html5/thumbnails/24.jpg)
Light as Waves• The wavelength of light is the distance
between troughs or between crests.
• Electromagnetic waves are made of both a magnetic and a electric field.
![Page 25: Placemat Activity: Different Types of Light](https://reader036.fdocuments.us/reader036/viewer/2022062521/568166d6550346895ddaed1b/html5/thumbnails/25.jpg)
The Electromagnetic Spectrum• Waves exist along a continuum of various wavelengths
• The smaller the wavelength, the higher in energy the light
• The longer the wavelength, the lower in energy is the light
![Page 26: Placemat Activity: Different Types of Light](https://reader036.fdocuments.us/reader036/viewer/2022062521/568166d6550346895ddaed1b/html5/thumbnails/26.jpg)
Homework Questions
• Read pages 403-410• Answer questions #1-7 (page 410)
![Page 27: Placemat Activity: Different Types of Light](https://reader036.fdocuments.us/reader036/viewer/2022062521/568166d6550346895ddaed1b/html5/thumbnails/27.jpg)