Now, when our mechanical wave travels through this region, through the ear canal, inside the ear canal, we have many air molecules. And as these air molecules vibrate back and forth, they eventually cause their eardrum, also known as our tympanic membrane, which is basically a membrane of a sort, the vibrations of the air molecules inside the ear that causes our membrane, the eardrum, to vibrate as well. So at the end of the ear canal, the mechanical wave hits and vibrates the eardrum, our tympanic membrane. Now, notice that the area of the eardrum is much smaller than the area of the pinna, this outside covering of our ear. Now, we know from physics that the pressure outside the ear is exactly the same, that the pressure is inside this region. But what is different is our area, because the area inside our eardrum, the area of the eardrum, is so much smaller than the area of the pin.