Shark Investigation

By Michael Minas

In term two of 2016, the year 2, 3 and 4 students who I was working with were studying animals.  During this time, they became interested in a number of current events related to this topic.  One of these was the death of a 60 year old diver in Western Australia after a shark attack and the subsequent decision to catch and kill the shark that was responsible.  We watched some news clips about the attack and in one, a police officer reported that the shark in question was estimated to be longer than 5.3 metres.  Given that we were also focussing on length, area and perimeter in our maths classes, it seemed like a good idea to connect the two topics in an attempt to make the learning more meaningful for the students.      

Students were first asked what tool they would use if they wanted to measure the length of a shark.  Numerous suggestions were made, including measuring tapes, rulers and trundle wheels.  The students were then placed in pairs and given a handout with the name, length and picture of a particular species of shark, which they were asked to keep secret from the rest of the class.

Each pair was then instructed to make a model that showed the length of their shark, using scrolls of paper.  They were free to use whatever tool they felt was best suited for measuring their shark accurately.  The lengths of the sharks ranged from 17 centimetres to 12 metres, so a variety of measuring devices were used, with some pairs starting with one tool and then deciding to switch to a more appropriate one midway through the activity.  At the end of the session, the students labelled the scrolls with their own names (e.g. Tom and Magnus’ shark) and they were collected by the teacher.

The next session, each pair was given a scroll that was made by another group, as well as a sheet which showed all of the different types of sharks and their average lengths.  Before doing any measuring, students were asked to estimate the length of their mystery shark and guess what species it might be.  Next, they measured the shark model, using the same range of equipment from the previous day.  Finally, they were asked to record what shark they now thought the model represented, based on their measurement.  Pairs were given a table to record this information and they tried to estimate and measure as many different sharks as they could in the allotted time.

One unintended, positive aspect of the activity was that it emphasised the importance of accuracy when measuring.  Some models were longer or shorter than they should have been, which caused great confusion for pairs who were working with these strips on day two.  This in turn lead to a really good class discussion about how these mistakes occurred and situations where we need to be extremely careful when measuring length.  The students were able to list a variety of examples where inaccurate measurement could lead to problems (e.g. being fitted for a suit or purchasing carpet for their bedroom). 

The level of engagement was very high throughout the two sessions, as the students could see a connection to the real-world and a clear purpose for the activity.  As part of our initial discussion on the moral issues involved in trying to catch and kill sharks, we discovered that only sharks that were longer than 3 metres were eligible to be put down under current West Australian law.  As many students were strongly opposed to this policy, they were extremely interested to discover which sharks could be killed and which breeds were safe. 

At the conclusion of the second session, students were asked to write a reflection on the activity.  Their responses indicated that they found the task interesting because of the clear connection between the maths and a current issue that many of them were passionate about.  A sample of some of the students’ reflections is included below. 

I really enjoyed it because I really like animals and measuring, so combining the 2 was fun.  I also enjoyed that it challenged me because I needed to work on my estimating, so it made me aware of that.  It was hard to make sure that we got it correct and measured exactly the right way. 

Phoebe

I found this activity fun because we got to measure sharks.  It was pretty easy at first, then it got harder because we had to estimate the length.  Me and my partner estimated the length by stepping one step and calling that a metre. 

Lachlan

I liked this activity because we got to learn about different species of sharks.  I thought our first shark was hard because we had to do the biggest shark.  It was almost bigger than the room.

Maddy

This activity was fun because we got to use lots of different equipment, like the metre ruler, measuring tape and also chalk. 

Demi

(This article originally appeared in Prime Number- Term 4, 2016.)