To accurately measure the wavelength between crests on a pier, you can follow these steps:
Set up a stable and fixed observation point: Find a location on the pier where you can have a clear and unobstructed view of the waves. Make sure you can maintain a consistent position throughout the measurement process.
Choose a reference point: Select a distinct feature or point on the pier, such as a post or a marking, as your reference point. This will help you maintain consistency in your measurements.
Start a timer: Begin timing when a crest passes your reference point. Use a stopwatch or a timer with high precision.
Count the number of crests: As the waves propagate, count the number of wave crests that pass your reference point. It is essential to maintain accuracy and focus while counting.
Stop the timer: Stop the timer when a specific number of wave crests has passed your reference point, or after a predetermined time duration that you want to measure.
Calculate the time interval: Divide the total time recorded by the number of wave crests counted. This will give you the time interval between successive wave crests.
Repeat the measurements: To improve accuracy, repeat the measurement process several times and calculate an average value for the time interval.
Measure the distance between crests: While observing the waves, use a ruler, measuring tape, or any suitable measuring device to measure the distance between two adjacent wave crests. Ensure that you measure from the corresponding points on each crest, such as the highest point or the lowest point.
Calculate the wavelength: The wavelength can be calculated by multiplying the time interval (from step 6) by the speed of the wave. The speed of the wave can be estimated if you know the depth of the water and the wave speed formula for that particular body of water. The formula generally used is v = √(gλ/2π), where v is the wave speed, g is the acceleration due to gravity, and λ is the wavelength.
Remember, this method assumes that the waves are regular and consistent, and that they are traveling in a straight line towards the pier. If the waves are irregular or if there are other factors affecting their behavior, the measurements may not be entirely accurate.