WAVES: SOUND & LIGHT © 2000 Microsoft Clip Gallery Attaullah Leghari DA Model High School Ph.VII

© 2000 Microsoft Clip Gallery “The difference between school and life? In school, you're taught a lesson and then given a test. In life, you're given a test that teaches you a lesson.In life, you're given a test that teaches you a lesson.”

OBJECTIVES To understand the following topics by using specific action plan: What are waves? How do these propagate? What do you know about Electromagnetic Waves and Spectrum? What do you know about the following characteristics of the waves: i. Reflection and Refraction ii. Interference and Diffraction

Using Bloom’s Taxonomy to develop higher order thinking in students. To relate 21 st century approaches with 21 st century skills in order to promote student centered learning. 4/29/20154 Long Term Goals

4/29/20155 Short Term Goals ANALYSING By the end of this lesson students will make a group discuss about the topic and write a report on it EVALUATING By the end of this lesson students will evaluate the their concepts through Q/A CREATING At the end of this lesson students will form a group and will present on the topic.

21 ST CENTURY APPROACHES TECHNIQUES\MODES21 ST CENTURY SKILLS Direction skills, Questioning skills, Monitoring skills Investigation, Tables, Worksheet Self direction, Critical thinking, social responsibility, communication skills, information and media literacy skills

7 I ‘ll focus on questioning skills I’ ll focus encouragement rather then praise I’ll work on creating collaborative groups or pairs I’ll successfully adopt 21 st century teaching approached in my class room November September January March

NATURE OF WAVES Waves (Def.) – A wave is a disturbance that transfers energy. Medium – Substance or region through which a wave is transmitted. Speed of Waves – Depends on the properties of the medium.

Electromagnetic Waves Speed in Vacuum –300,000 km/sec –186,000 mi/sec Speed in Other Materials –Slower in Air, Water, Glass © 2000 Microsoft Clip Gallery

Electromagnetic Spectrum Visible Spectrum Invisible Spectrum

Electromagnetic Spectrum Visible Spectrum – Light we can see –Red, Orange, Yellow, Green, Blue, Indigo, & Violet. –Largest to Smallest Wavelength.

Electromagnetic Spectrum Invisible Spectrum –Radio Waves Def. – Longest wavelength & lowest frequency. Uses – Radio & T.V. broadcasting. © 2000 Microsoft Clip Gallery

Short Wavelength Microwave Invisible Spectrum (Cont.) –Infrared Rays Def – Light rays with longer wavelength than red light. Uses: Cooking, Medicine, T.V. remote controls

Electromagnetic Spectrum Invisible spectrum (cont.). –Ultraviolet rays. Def. – EM waves with frequencies slightly higher than visible light Uses: food processing & hospitals to kill germs’ cells Helps your body use vitamin D.

Electromagnetic Spectrum Invisible Spectrum (Cont.) –X-Rays Def. - EM waves that are shorter than UV rays. Uses: Medicine – Bones absorb x-rays; soft tissue does not. Lead absorbs X-rays.

Electromagnetic Spectrum Invisible spectrum (cont.) –Gamma rays Def. Highest frequency EM waves; Shortest wavelength. They come from outer space. Uses: cancer treatment.

Refraction of Light Refraction – Bending of light due to a change in speed. –Index of Refraction – Amount by which a material refracts light. –Prisms – Glass that bends light. Different frequencies are bent different amounts & light is broken out into different colors.

Reflection Reflection – Bouncing back of light waves –Regular reflection – mirrors smooth surfaces scatter light very little. Images are clear & exact. –Diffuse reflection – reflected light is scattered due to an irregular surface.

Diffraction Diffraction – Bending of waves around the edge of a barrier. New waves are formed from the original. breaks images into bands of light & dark and colors. Refraction – Bending of waves due to a change in speed through an object.

OUTCOME Waves carry energy from one place to another Waves can bounce back (reflect) and change their path (refract) if these pass through any transparent medium. Waves also bend around the edges of the barrier (diffract)..

OUTCOME Radio waves, light, and x-rays are different wavelength bands in the spectrum of electromagnetic waves. Sound is a longitudinal wave whose speed depends on the properties of the medium in which it propagates.

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