Let's take a look at the inside of an ear. Roll the computer graphics.
If someone says 'hello, hello' that sounds enters my head through the ear canal and hits the ear drum which vibrates when the sound waves hit it. Behind the drum in the middle ear cavity are there tiny bones: stirrup, the anvil and the hammer, they vibrate too and actually amplify the sound. They send the amplified sound vibrations to the cochlea which looks sort of like a snail. The sound waves travel around and around inside the cochlea and bend over tiny nerve endings called hair cells, much like wind pushes around a field of grain. These hair cells are the ends of nerve cells and the movement of the hair cells sends electrical signals to the brain. The brain decodes those signals and, I hear (runs tape backwards) 'hello, it's your mother'. So that's how our hearing works.
But what happens when an ear is subjected to hazardous noise. Let's go back to those hair cells. If those hair cells get bent over to the point they can't spring back, that's when hearing loss occurs.
It's like these blades of grass. Imagine they're the hair cells in your ears. Now here comes a moderately loud sound wave (moderately loud noise) Not bad, the grass bounces back. But when the sound is extremely loud (extremely loud noise) the hair cells don't spring back, extremely loud sounds can cause permanent damage, but so can moderately loud sounds if they continue over an extended period of time.
(Moderately loud classical music plays continuously)
Long exposures to moderately loud sounds can do just as much harm as one really loud sound (sound of car jet engine). Both situations are hazardous. Fortunately for the lawn grass will grow back or can be replaced. Not so for your ears, the hair cells never grow back, EVER! And they can't be replaced.
(Sound of wind blowing)
So, how do you choose what hearing protection is best for you, what are the deciding factors concerning you and your job.
Well, one consideration should be your current hearing ability.
Also your exposure to noise over the whole day.
(Sound of petrol mower)
(Shouts) Your need to communicate on the job.
(Comedy sketch - The Stooges)
Other personal protective equipment you wear (points at safety glasses).
(Howling wind) Temperature (Hawaiian sounds) and climate.
The physical constraints of the work activity. And anatomical differences. Once you've chosen the right hearing protection for you, there's only two things to remember, its fit and its care. It's essential that your hearing protection fits properly, let's go to the demonstration tank.
It's kind of like this, imagine the water is hazardous noise, the drain is your ear and the stopper is your ear plug. If it fits perfectly the noise stays out, but if you put in a plug that's too small. The noise gets through. Remember those hair cells. It's the same with ear muffs, they have to fit snug too. Just like this stopper, if the seal is broken anywhere the water or noise will flow in. Watch!
(Demonstrates with the water tank)
Although it takes a while noise does get through.
With so many choices of styles and sizes it's easy to ensure your hearing protection will be affective and it won't take long to get used to wearing it.
Just look at all those colours.
Taking care of your hearing protection is easy too, it's just a matter of cleaning it regularly and inspecting it for damage. If it's damaged replace it.