Henry's dives

We have provided some graphs for you to view here which provide an insight into the depth (in metres, down the graph) and time (in minutes, across the graph - left to right) that Henry has been under water. The top of each graph is the surface of the sea, the bottom of each graph is 65 m below the sea surface (quite an amazing depth don't you think?) The graph on the right is a record of all Henrys dives. The white spaces are the time that Henry has spent ashore, or at least not diving. The dives are indicated by the blue lines, so as they reach the bottom of the graph they indicate the deeper Henry went on that particular dive. The deepest dive shown on the right has been used on this page so that we can investigate more about the type of dives Henry makes. The red line (with arrows) shows what part of the graph is shown in the next image as an enlargement, so you can see more and more details.

In this first graph there are a lot of dives. It covers a day and a half of Henrys time diving at sea. If you notice the number of blue lines over this day and a half you will note that he hardly stopped diving! The almost sold blue lines means that he was almost constantly diving to the seafloor, only coming to the sea surface to breathe for a minute or two between dives.

 

Now we have taken a section of the above graph, marked with the red line, and enlarged it. The graph below now shows a period of eighteen hours of Henrys diving. Now you can really start to see the shape of each dive that Henry made over this period. In these eighteen hours, Henry made almost one hundred dives, and it shows some of the depths he went too to catch his fish and squid. Remember the bottom of the graph indicates a depth of 65 metres.

We have now taken another section from the graph above end enlarged it to show a series of about fifteen dives. Now you can clearly see the exact shape of each dive. The dives indicate that Henry travelled from the sea surface very quickly (the line from the top to the bottom is almost straight), until he reached the seafloor, where he stopped and searched around for fish and squid that live on the seafloor. If you look at each dive in this graph, you can see that Henry swam into a more shallow area, because his dives got shallower and shallower. This is when Henry was on his way back to North Page Island, so as he got closer and closer to land, the depth of the water got shallower and shallower!

The bottom graph shows one dive in the middle, enlarged from the above graph, but also the amount of time that Henry spent at the sea surface before and after the dive. The dive in the middle went to 65 metres and before and after this dive Henry spent about two minutes at the sea surface, breathing deeply to get ready for the next dive and recovering from the previous dive. This graph also shows what Henry was doing on the seafloor. You can tell that the seafloor is almost flat (no big rocks around) because the bottom part of the graph is almost flat, which shows us that Henry did not have to swim up and over any deep crevices in search of his food, at least not on this dive.