Exploring Wave Properties What happens to the water when you drop a pebble into a pond? ACTIVITY 1: WAVE IT! Direction: Listen to the instruction of the teacher and the procedure to do. ACTIVITY 1: WAVE IT! Hold the Slinky between your hands—it will be horizontal and will sag. Move both of your hands up and down together. Grab the ends of the slinky in your hands. Stretch the slinky to between 1 and 2 meters long. Move your hands together and then apart, just as if you were clapping. Notice the motion of the slinky. Your hands move a lot while the center of the slinky moves very little. ACTIVITY 1: WAVE IT! GUIDE QUESTION: 1. What did you observe while doing the activity? 2. What is the direction of the wave in the slinky? 3. What is the direction of the wave in the rope? What is a Wave? •A wave is a disturbance that moves through matter or space. •Waves carry energy from one place to another. •Waves Carry Energy, not Matter Did you know? Olympic divers try to enter the water without making splashes or waves when they do high dives. Minimal splashing or disturbances in the water mean the diver is demonstrating excellent technique, body control and synchronization of movements. Mechanical Wave •Mechanical waves are waves that must travel through some form of matter to carry their energy. •The matter that carries a wave is called the medium and includes matter such as air, water, rock, metal, etc. •Mechanical waves can be either transverse or longitudinal waves. Electromagnetic Wave •EM waves are waves that can travel through empty space. They do not require a medium. •EM waves are transverse waves. •EM waves travel through space at the speed of light. Types of Waves Transverse waves move up and down or side to side waves in which the vibration of the medium is parallel to the direction the wave travels Parts of a Wave Crest Wavelength Amplitude Rest Position Trough Crest The highest point of a wave Trough The lowest point of a wave Amplitude The height or size of a wave Wavelength The distance from one wave to another Normal Line / Resting line Line through the center of the wave. Parts of a Wave Rarefaction A rarefaction is a region in a longitudinal wave where the particles are furthest apart. Compression A compression is a region in a longitudinal wave where the particles are closest together. Wave Frequency Number of complete cycles or waves that occur in a given amount of time, measured in hertz (Hz). Frequency is the number of waves that pass a point in a certain period of time. High-frequency music has lots of quick changes in the sound waves, and it feels fast and energetic. Low-frequency music has slower changes in the sound waves, and it feels calm and soothing. Wave Frequency • Frequency and wavelength are inversely proportional with each other. • High Frequency, short wavelength • Low Frequency, long wavelength Wave Velocity How fast a wave moves from one place to another, measured in meters per second (m/s) or kilometers per hour (km/h) Distance Speed= Time If a wave travels 10 meters in 2 seconds, its speed would be 5 meters per second. 5s= 10m 2s Wave Velocity The formula for the wave velocity; speed equation: wave speed= wavelength x frequency Wave speed (v) = m/s Wavelength (λ) = m Frequency = Hz/hertz Wave Velocity Sample Problem 1: A wave has frequency of 50 Hz and a wavelength of 10 m. What is the speed of the wave? Given: Frequency = 50 Hz Wavelength (λ) = 10 m Wave speed (v) = ? Formula: v = wavelength (λ) x frequency = 10 m x 50 Hz (s) Wave speed (v) = 500 m/s Wave Velocity Sample Problem 2: A wave with a frequency of 14 Hz has a wavelength of 3 meters. At what speed will this wave travel? Given: Frequency = 14 Hz Wavelength (λ) = 3 m Wave speed (v) = ? Formula: v = wavelength (λ) x frequency = 3 m x 14 Hz (s) Wave speed (v) = 42 m/s Wave Velocity Try Problem 1: A wave has a frequency of 46 Hz and a wavelength of 1.7 meters. What is the speed of this wave? Given: Frequency = Wavelength (λ) = Wave speed (v) = Formula: v = wavelength (λ) x frequency = Wave speed (v) = m/s Wave Velocity Try Problem 2: A wave has a wavelength of 0.5 meters and a frequency of 120 Hz. What is the wave’s speed? Given: Frequency = Wavelength (λ) = Wave speed (v) = Formula: v = wavelength (λ) x frequency = Wave speed (v) = m/s Do This! Research and define the following words and we will be having a recitation next meeting. 1. Sound 2. Loudness 3. Pitch THANK YOU FOR LISTENING! Light Wave The distance of one wavelength is measured in nanometers (nm). The period is measured in seconds (s). In waves, like sound or light waves, the period is the time it takes for one complete up-and-down motion of the wave. Fun Fact Did you know that dolphins use sound waves in the ocean to navigate the ocean? When dolphins make sounds, these sounds travel through the water and bounce off objects like fish or rocks. Then, the dolphins listen for the echoes or the bouncing sounds that come back to them. By using echolocation, dolphins can determine the location, size, and shape of objects around them.
