Waves and Their Applications - Unit 1, Module L

Waves and Their Applications - Unit 1, Module L

• Standard MS-PS4-2: Develop and use a model to describe that waves are reflected, absorbed, or transmitted through various materials.

Day 1 - Light Reflection

• Objectives:
  • Define reflection
  • State the law of reflection
  • Draw ray diagrams of light reflection
  • Explain how reflection allows us to see objects
  • Predict the angle of incidence from the angle of reflection

Keywords

• Reflection
• Incident ray
• Reflected ray
• Angle of incidence
• Angle of reflection

Starter Activity

• Use a flashlight or laser pointer and a mirror to demonstrate how light reflects off a surface. Observe how light behaves on a shiny surface.

Reflection

• Reflection is the bouncing of light off a surface.
• Luminous objects emit their own light (e.g., flame, firefly, bulb, sun, stars).
• Non-luminous objects do not emit light but reflect light from a source (e.g., ball, tree, house, cloth, moon, earth).

Luminous Objects

• Firefly
• Torch
• Bulb
• Fire
• Sun
• Stars

Non-Luminous Objects

• Ball
• Moon
• Earth
• Tree
• Cloth
• House

Direction of Light

• Light waves travel from their source in all directions.
• When a light wave hits an object, it may change direction.
• Light travels in a straight line until it hits a surface (light ray).

Group Discussion

• Light rays did not enter the eyes, so the object is not visible

How Do We See Objects?

• Light from a source (like the sun) falls on an object.
• The object reflects light in all directions.
• The reflected light reaches our eyes.
• Our brain receives the information from our eyes, allowing us to see the object.

Checking Understanding

• Describe how you can see any object in your classroom.

Law of Reflection

• When a ray of light reflects off a surface, the angle of incidence is equal to the angle of reflection.

Independent Activity

• Find the angle of reflection

Check Your Understanding

• Calculate angle I and angle r

Peer Assessment

• If the angle of incidence is 20 degrees, the angle of reflection is 20 degrees.
• If the angle of incidence is 45 degrees, the angle between the incident ray and the reflecting surface is 45 degrees.

Day 2- Day 4 Information

• Day 2: Parent-Teacher conference (early dismissal)
• Day 3: Assessment 2
• Day 4: Project - Identifying Waste Issues in the School. Conduct a waste audit, categorizing types of waste and recording their amounts.