Presentation on theme: "1. Place 5 marbles along the groove in the ruler as shown on your handout. 2. Now take a 6 th marble and flick it against the end of the row. 3. Draw."— Presentation transcript:
1. Place 5 marbles along the groove in the ruler as shown on your handout. 2. Now take a 6 th marble and flick it against the end of the row. 3. Draw what happens. 4. Describe what happens using complete sentences. 5. Why did this happen? Make sure you are using the correct science vocabulary words.
Sound is a type of energy made by vibrations. When an object vibrates, it cause movement in the air particles. These particles bump into the particles close to them, which causes them to vibrate too. This causes them to bump into more air molecules This movement, as energy is passed from one molecule to another is called sound waves. If your ear is within range of the vibrations, you hear the sound.
Sound needs a medium to travel Sound is a mechanical wave and needs a medium for propagation or transmission. Sound travels through solids, liquids and gases. Sound does not travel in vacuum. Vibrations create sound. Vibrations are created from molecules moving back and forth.
Pitch-the highness or lowness of a sound Sound- a series of vibrations that you can hear Intensity-the measurable amount of a property, such as force, brightness, or a magnetic field. Amplitude-the distance from crest to rest, trough to rest position of the water. Vibration- the back and forth movement of a molecule vocal chords- are part of your throat that vibrates when you speak Echo- a sound reflection
1. Stretch the thin long rubber band between your hands as shown in the diagram. 2. Have your partner pluck the center of the rubber band. What do you hear? 3. Now repeat this with the thick rubber band. What do you notice is the difference in sound? 4. What is the medium?
Sound needs a medium to travel Sound is a mechanical wave and needs a medium for transmission. Sound travels through solids, liquids and gases. Sound does not travel in vacuum.
Compressions are the regions of high pressure and density where the particles are crowded and are represented by the upper portion of the curve called crest. Rarefactions are the regions of low pressure and density where the particles are spread out and are represented by the lower portion of the curve called trough.
1. Place a ruler on the counter so that about half of the ruler sticks out beyond the counter’s edge. 2. Hold the ruler down firmly with one hand. With the other hand, press down on the free end of the ruler, then snap up. 3. Did you see the ruler vibrate? 4. Did it make a sound? 5. What is the medium? 6. Move the ruler so that les is hanging off the edge. How does the sound change?
Pitch and loudness of sound :- The pitch of sound (shrillness or flatness) depends on the frequency of vibration. If the frequency is high, the sound has high pitch and if the frequency is low, the sound has low pitch. Wavelength, Frequency, and Pitch Since the sounds are travelling at about the same speed, the one with the shorter wavelength will go by more frequently; it has a higher frequency, or pitch. In other words, it sounds higher.
Reflection- occurs when a wave strikes an object and bounces off it- all types of waves can be reflected (ex. Sound, water, & light)
Refraction- bending of a wave caused by a change in its speed as it moves from one medium to another. Refraction occurs when waves pass through an object. Pencil in water looks broken due to refraction
Diffraction- an object causes a wave to change direction and bend toward it. Diffraction occurs when waves pass around an object The greater the speed the more the wave bends
Electromagnetic Waves- made by vibrating electric charges and can travel through space. Electromagnetic Spectrum- the entire range of electromagnetic wave frequencies
Electromagnetic Spectrum includes: Radio waves-low frequency waves with wavelengths of about 1-10 cm (radio stations, microwaves, radar) Infrared waves-have slightly higher frequency than radio waves (remote control, warmth of fire, satellites) Visible light- range of electromagnetic waves you can detect with your eyes (ROYGBIV- different colors from different wavelengths) Ultraviolet waves-frequencies slightly higher than visible light (sunburns, fluorescent materials absorb it, vitamin D production, kills bacteria) X-rays & Gamma Rays- ultra high frequencies that can travel through matter, damage cells (bones images, radiation therapy)