Final answer:
As waves approach the shore, their speed and wavelength decrease, while their height and steepness increase. The steepness of the beach influences how the waves break, with steeper beaches potentially causing more erosion due to the sudden breaking of waves with more energy.
Step-by-step explanation:
As waves travel towards the shore, they undergo a series of changes, resulting from their interaction with the gradually shallowing sea floor. The speed of the wave decreases because the energy of the wave is spread over a shorter vertical column of water. Consequently, the wavelength also decreases, as the waves bunch closer together. As the depth of the water decreases, the height of the wave increases, which is often referred to as wave shoaling. The wave becomes steeper due to the increase in height and the decrease in wavelength. If the steepness reaches a certain critical level, the wave becomes unstable, and it starts to break, creating the 'grand finale' on the shore that surfers might ride.
When considering the impact on the shore, waves with higher amplitude cause more erosion and therefore have the potential to be more damaging. The frequency and amplitude of the waves, the beach slope, and the type of seabed all influence the exact nature of the break. A steeper beach can cause waves to break more suddenly and with greater energy, which can lead to increased erosion.