Activity: Reef Break/Beach Break

On SCOPE's Surfing Science episode, a group of friends investigated what sort of break produced the best surf for a surfer, a beach break or a reef break. There is a third fairly common break that they did not test, and it is a point break. You could use the same method to see how a point break compares to one of the others. But first here's what they did:

The girls on the beach working out who will do which job.

What you need

• Someone to surf the waves (and a surfboard).
• A time recorder to time the rides.
• Someone to count the number of tricks.
• Finally someone to bring all the numbers together (they might want to bring a calculator).

What to do

1. Try and pick a day when you have fairly constant weather conditions.
2. At each break, have your surfer catch 5 waves.
3. For each ride, count the number of tricks and time the length of the ride from the shore.
4. The surfer can then give you a signal from 1 - 5 for wave speed after each ride.
5. Find an average for each of the 3 lots of data (length of ride, tricks and wave speed)
• To do this for 5 numbers, simply add them all together and divide by 5.
6. Head off to the second break and repeat the experiment.

What's happening?

A reef break is where waves break on rocks on the bottom of the ocean floor and a beach break is where a wave breaks over the shallow sandy bottom. A point break is a little different. It is when a wave breaks as it hits a point of land jutting out from the coastline.

Waves break because of the friction between the sea floor and the wave. This friction slows down the bottom of the wave and gradually the top of the wave overtakes it until it begins to topple over, or break. Even though a point break doesn't directly refer to the type of sea floor (as with the beach and reef breaks), the shape of the coast is also crucial in shaping the way the wave breaks. For more information visit this website.

The first requirement of this experiment is to try and have constant weather conditions. This is because the weather (mainly the wind) has a large effect on the surf too. So if you are testing how the coastline and sea floor effect surf conditions, you don't want the wind interfering with your results.

As an additional experiment, and just to be really scientific, it would be a good idea to repeat the experiment under several different conditions (on-shore and off shore winds, high and low tides) to see which break is best under which conditions, and which is best overall. Gee, that's a lot of surfing, in the name of science.