From what I have learned so far a wave propogates on a string by having the point on the string (that is closest to the wave and in the direction the wave is moving) move upwards or downwards depending on the wave and this point moving due to tension causes the next to move simillarly and thus the wave propogates through the string. My problem comes from when there is lets say an equal yet oppisite wave moving on the string and they meet. According to me at this point because the point in question will have equal reason to move both up and down it will stay in position and the both waves will collapse or be reflected I don't know. I know that I am wrong as the waves do pass through eachother I just want to know why? thanks for your help. PS: This is my first post though google has lead me here for years.