Module 2 Light • Lesson 1: How light travels • Lesson 2: Reflection and Mirrors • Lesson 3: Refraction and Lenses • Lesson 4: Color of Light Module 2 Light: L1 How Light Travels Learning Objectives • Use models to describe light’s path • Describe how objects function to interact with light waves through, reflection, absorption and transmission Traveling Waves p.65 Sound and light waves both travel by waves. In order to hear sound or see light, waves must travel from one place to another and enter either your ears or eyes. How do you think these waves travel? Circle the response that best matches your thinking. A. One needs to travel through matter B. Neither needs to travel through matter C. They both need to travel through matter What is Light? • • • • • Neither matter or energy Light carries energy and travels as a wave. Light waves travel in straight lines. Light is a electromagnetic radiation Light travels at 300 000 000 m/s or 300 000 km/s (much faster than sound). p.70 Electromagnetic Spectrum • HW: p. 71 Properties of Light • nanometers(nm) What is the difference between mechanical waves and electromagnetic waves? Waves and Energy Mechanical Waves • The more energy the wave has, the greater the wave’s amplitude Electromagnetic Waves • The more energy the wave has, the higher the wave’s frequency Higher Frequency= Higher Energy Speed of Light p.74 Questions • What do you observe about the speed of light? • Light waves slows down when they travel through matter. • How many times faster is the speed of light than the speed of sound? • 900,000 times faster Compare Light and Sound Waves p.74 Compare at least 5 characteristics Compare Light and Sound Waves -Ans • Both light and sound are waves • Sound waves require a medium to travel through, and the • They both have wavelengths and denser the medium, the faster frequences. they travel. • The energy of a sound waves is • Light waves require no medium related to its amplitude and the denser the medium is, • The energy of a light wave is the slower they travel related to frequency Light Interactions of Matter • Evidence needed for Light(p.77) • Transmission • Absorption • Reflection Write down what you think the following words mean: Make this into a fill in the blank activity to 1. 2. 3. 4. 5. 6. Transparent Opaque Translucent Transmit Reflect Absorb practice! 1. 2. 3. 4. Transparent: objects that transmit light and you can see through them Opaque: objects that absorb, scatter, or reflect light and do not allow any light to pass through Translucent: Objects that transmit light but diffusing(scattering) light as it passes through Transmit: When light or other radiation passes through an object 5. Reflect: bounce off 6. Absorb: taken into a material Light Pollution • https://www.nationalgeographic. org/video/light-pollution-101/ (Taiwan) EPA to introduce guidelines on light pollution at night • https://en.rti.org.tw/news/view /id/2002102 • https://www.darksky.org/ourwork/conservation/idsp/parks/h ehuanmountain/ Homework • p.82-84