Preconceptions Summary
Student preconceptions (misconceptions, naïve understandings) are important for teachers to uncover, address, challenge and extend. These are commonly held (but not always scientifically accurate) ideas that children bring to the classroom. Students come to school with ideas about the world and science principles because of experiences and observations that have helped to shape those beliefs. Learners hang onto those ideas until multiple experiences cause them to question previously-held beliefs and to form new explanations.
Educators need to discover student preconceptions and be aware of the related scientifically accurate ideas. It is the teacher’s role to facilitate learning experiences that challenge inaccurate ideas, solidify developing ideas, and reinforce and extend scientifically accepted ideas. Knowing student preconceptions helps educators to ask probing questions and craft experiences to move students along to greater science understanding.
Below is a summary of the preconceptions and scientifically accurate ideas related to the Physics of Sound:
Preconceptions about Sound:
Sound is a thing. There is no relationship between vibration and sound.
Sound is invisible and can only be heard. We need to see vibration to know it’s there.
Scientifically Accepted Ideas:
Sound is a vibration, a disturbance in the medium around it.
Preconceptions about Sound:
Reflected sound is when sound waves hit an object and then go back to the source. Ambient sound fills the spaces as if it were a fluid of sound. Sound only bounces off solids.
Scientifically Accepted Ideas:
Sound waves move out from a vibrating object. If obstructed by an object it is reflected and turned back to yours ears.
Ambient sound is made up of reflections from walls and other obstacles that can produce a complex network of sound signals from a single source.
Preconceptions about Sound:
Students may think that sound cannot harm them.
Scientifically Accepted Ideas:
Loud sounds (sound waves with large amplitude) can damage ears permanently. Sound at levels over 90 decibels have been found to permanently damaged human ears. (i.e., heavy trucks – 100bd, power saw - 110db, thunder – 130db)
Preconceptions about Sound:
Only living things are associated with energy, in particular with growing, fitness, exercise, and food.
Scientifically Accepted Ideas:
Some forms of energy, such as light, sound and chemical energy, can be used to make things happen.
Preconceptions about Pitch:
Pitch and volume are the same. If the pitch changes, volume has to change too.
Scientifically Accepted Ideas:
Frequency of vibration determines pitch.
Preconceptions about Pitch and Volume:
Bigger vibrations are slower than small vibrations.
Scientifically Accepted Ideas:
Length of vibrations determine volume, not pitch.
Preconceptions about Sound Waves:
Students may not think that waves are in musical instruments.
Scientifically Accepted Ideas:
Standing waves are set up in many musical instruments.
Preconceptions about Sound Travel:
The sound travels from the ear to the source and/ or that the sound travels back and forth from the source to the hearer.
Scientifically Accepted Ideas:
Sound travels from the source to hearer.
Preconceptions about Sound Travel:
Sound doesn’t travel through solids, it only travels through the air. Air isn’t a medium, it’s “nothing.”
Scientifically Accepted Ideas:
Sound travels through mediums: solid, liquid, gas.
Preconceptions about Sound and Light speed:
That thunder is not related to lightning. You’re safe if you can detect a time period between thunder and lightning. Sound travels at only one speed.
Scientifically Accepted Ideas:
The speed of sound (about 700 miles/second) is much slower than the speed of light. (about 186,000 miles/seconds)
Preconceptions about Hearing:
The ears look for the sound and pick it up just the way we hear it, and/or that there is a hearing ray that comes out of the ears to find the sound.
Scientifically Accepted Ideas:
Ears are receivers that convert vibrations to an electrical signal to our brain.
|
|
