Sound

Activity #1: Cannonball! Place 5 marbles along the groove in the ruler as shown on your handout. Now take a 6th marble and flick it against the end of the row. Draw what happens. Describe what happens using complete sentences. Why did this happen? Make sure you are using the correct science vocabulary words.

What is Sound? 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 Sound needs a medium to travel Vibrations create sound. 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.

Sound Vocabulary Amplitude-the distance from crest to rest, trough to rest position of the wave. (VOLUME) 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 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.

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.

Activity #2: Rubber Band Vibrations Stretch the thin long rubber band between your hands as shown in the diagram. Have your partner pluck the center of the rubber band. What do you hear? Now repeat this with the thick rubber band. What do you notice is the difference in sound? What is the medium?

The higher the amplitude the louder the sound. The lower the amplitude the softer the sound.

How loud a sound is depends on the amplitude! HIGH amplitude is LOUD low AMPLITUDE is quiet

The higher the frequency , the higher the pitch. The lower the frequency, the lower the pitch.

High Pitch Low Pitch

Low Pitch High Pitch

Activity #3: Singing Ruler Place a ruler on the counter so that about half of the ruler sticks out beyond the counter’s edge. Hold the ruler down firmly with one hand. With the other hand, press down on the free end of the ruler, then snap up. Did you see the ruler vibrate? Did it make a sound? What is the medium? Move the ruler so that les is hanging off the edge. How does the sound change?

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.

Activity: Tap- Tap- Tap Listen carefully as you tap your finger firmly and loudly against the table/ counter. Now lay your ear on the table/ counter, and tap your finger loudly and firmly again. Questions to think about! Which time did you hear the sound of your tapping finger the loudest? Based on this experiment, does sound travel better through solid materials (table) or gas materials (air)?

How does sound waves travel? Sound waves’ vibrations are parallel to the movement of the wave. Sound travels faster through solids. Sound waves travel in all directions but sound waves travel fastest in a solid. Solid Liquid Gas These vibrations are parallel to the movement of the wave

Sound Travels Through Matter Gases Most of the sounds we hear travel through gases, such as air. Sound waves travel slowly through the air. For example: Sound from a bell, a horn, or an alarm clock travels through the air. Liquids Some sounds that we hear travel through water. Sound waves travel a faster through water than through the air. Sonar is the way to use sounds to locate objects under water. What animals use sonar? Solids Some sounds that we hear travel through solids. Sound waves travel very fast through solids. For example: When you hit a drum, it vibrates, then the sound travels through the air, to your ears.

How do we hear sound?

The Outer Ear: Pinna or Auricle The outer ear also includes the ear canal, where wax is produced. Earwax is that gunky stuff that protects the canal from bacteria and dirt to keep the ear canal clean. The outer ear, pinna, catches the wave This is the part of the ear that people can see. The main job of the outer ear is to collect sounds, whether they're your friend's whispers or a barking dog. It's what people pierce to wear earrings and what your friend whispers into when it's time for a secret.

The Middle Ear: Good Vibrations After sound waves enter the outer ear, they travel through the ear canal and make their way to the middle ear. The middle ear's main job is to take those sound waves and turn them into vibrations that are delivered to the inner ear. To do this, it needs the eardrum, which is a thin piece of skin stretched tight like a drum. The eardrum separates the outer ear from the middle ear and the ossicles Ossicles are the three tiniest, most delicate bones in your body: Malleus- attached to the eardrum Incus- is attached to the malleus Stapes -the smallest bone in the body, which is attached to the incus

The Middle Ear: Good Vibrations When sound waves reach the eardrum, they cause the eardrum to vibrate. When the eardrum vibrates, it moves the tiny ossicles — from the hammer to the anvil and then to the stirrup. These bones help sound move along on its journey into the inner ear.

The Inner Ear: Nerve Signals Start Here Sound comes into the inner ear as vibrations and enters the cochlea Cochlea- a small, curled tube in the inner ear. The cochlea is filled with liquid, which is set into motion, like a wave, when the ossicles vibrate. The cochlea is also lined with tiny cells covered in tiny hairs that are so small you would need a microscope to see them. When sound reaches the cochlea, the vibrations (sound) cause the hairs on the cells to move, creating nerve signals that the brain understands as sound. The brain puts it together and hooray! You hear your favorite song on the radio.

Human hearing is limited to a range of sounds. Humans cannot hear sounds that vibrate: too fast (pitch is too high) too slow (pitch is too low) too large (volume is too loud) too small (volume is too soft)

What causes damage to hearing? Exposure to loud noise. Head trauma. Virus or disease. Autoimmune inner ear disease. Hearing loss that runs in the family. Aging Malformation of the inner ear.

How Sounds Are Made We use our vocal cords to make sounds in our throat. When we speak, our vocal cords vibrate. Place your hand on your throat when you talk, and you can feel the vocal cords vibrate.

Can your vocal cords become damaged? Voice Misuse/ Overuse-excessive talking and screaming Throat Cancer Laryngitis

Group Discussion: Tuning a Fork and Straw Music? What did you observe? What is the medium? Was a sound created? What did you hear? What did you see? What appeared to be vibrating?

Sound is a longitudinal wave

A vibrating object producing a series of compressions (C) and rarefaction (R).

Let’s Review!!!!

Review Sound waves are sent. The outer ear “catches the sound waves”. The middle ear takes the sound waves and “vibrates” the eardrum. The inner ear sends the messages to the brain. Middle Ear Outer Ear Sound Waves Inner Ear The brain puts it together and hooray! You hear your favorite song on the radio.