SOUND
Vibrations cause all sounds.
Sounds have to travel through a medium. Ex: air, water, solid object (door, etc.)
Sound travels faster through materials that have more closely packed particles.
Quiet: soft "whaps"
Low Pitch: infrequent vibrations, bigger things
Loud: hard "whaps"
Amplitude or Intensity: loudness or softness of a sound
Vibrations cause all sounds.
Sounds have to travel through a medium. Ex: air, water, solid object (door, etc.)
Sound travels faster through materials that have more closely packed particles.
- air= 1 mile in 5 seconds
- ocean water= 4 times faster than in air
- steel= 15 times faster than in air
Quiet: soft "whaps"
Low Pitch: infrequent vibrations, bigger things
Loud: hard "whaps"
Amplitude or Intensity: loudness or softness of a sound
- depends on the strength with which the sound producing object is vibrating
- depends on the rate (frequency) at which the object is vibrating (more vibrations per second, higher the pitch)
- Ex: trumpet vs. flute
Demonstrations:
1. Used a slinky to represent vibrations in air molecules that cause sound.
1. Used a slinky to represent vibrations in air molecules that cause sound.
- Have students hold the ends of the slinky and stretch it out across the floor.
- One student then proceeds to move the slinky in a back forth motion, demonstrating different frequencies and force
- This allows them to see the "sound waves" while listening to the high and low pitches, and loud and quiet sounds
2. Blow in 2 glass bottles.
- Fill 1 bottle 2/3 full of water
- Blow in the bottles and listen to the difference in sound
- The smaller the space in which the vibrations can travel, the higher the pitch
3. Blow into a straw.
- Cut the end of a thick straw into a V shape.
- While you blow into the straw, cut sections of it off so the students can hear the pitch getting higher.
4. Vibrations seen through salt.
- Lay plastic wrap on top of an open aluminum can. Sprinkle salt on top of the plastic wrap.
- Using metal prongs, tap the table. Hold the prongs close to the salt and watch the vibrations bounce off the prongs and make the salt particles move around.
5. Oven rack experiment.
- Tie strings, with loops on both ends, to an oven rack.
- Have student put fingers through the loops and into ears.
- Let oven rack hang loosely.
- Have another student run objects down the oven rack, like an instrument.
- The noise is very loud to the person with fingers in their ears.
6. Guess what's inside the plastic eggs.
- Fill eggs with objects such as: sand, baking soda, marbles, tacks, coins, macaroni, toothpicks, beans, cork, etc.
- Have students shake the eggs and write down what they think is inside of them.
7. Rubber bands on a cup.
- Have students explore different sized rubber bands by placing them around plastic cups.
- They will then be able to decipher ways in which to make different sounds with these two materials.
- Examples:
- Thicker bands have deeper sound.
- The closer to the middle of the cup the bands are placed, the deeper the sound will be.
- Squeezing the cup changes the sound.
- Sound is louder when you pull with fingers and quieter if you tie two rubber bands together and pull with the second band.
- If you flip the cup upside down, the pitch changes because the band is hitting the cup, not just air.
- Harder pulls result in louder sounds.
- The tighter the band is, the higher the pitch will be.