3 Snakes - fun in the jungle

A Rationale for using the app

When children first meet the idea of measuring, we tend to use informal ways of describing how long an object is. For example, we could measure with hand spans and use them as a way of describing how long the object is. The more hand spans, the longer the object; the fewer the hand spans, the shorter the object. Well, with snakes in the jungle, measuring with hand spans is NOT a good idea! Instead, we can count the humps that the snakes make as they wriggle along. Counting humps is an informal measure of length that is a completely natural way in which the introduce children to the concepts of long, longer and longest as well as short, shorter and shortest.

If you want to find out if the green snake is longer than the blue snake, count humps and the snake with the most humps will be the longest, while the snake with the least humps will be the shortest. So when we ask the child how they know which of two snakes is the longer, or whether two snakes are the same length, we can also show them how to check a visual impression by actually counting humps. In doing this we are giving them the right tools for comparing lengths in many other contexts and are building a natural understanding of length concepts.

In the classroom

Although 3 Snakes is an app that can be used by individual players, it is also a resource that can be used in the classroom. The following lesson plan and activity may help you to make the most of this app with a group of students or the whole class.

Origins of 3 Snakes

When we first had the idea for this app, it was in the form of a flipper book in which two halves of the snakes (the left half and the right half) could be changed independently. Thanks to the wonders of the iOS coding language, the book has been replaced by a screen in which the left and right halves can be manipulated independently. When you press the arrows on the left, the head parts of the 3 snakes change in length and similarly for the buttons on the right.

Now for the maths of it all!

Going from top to bottom, the left halves of the 3 snakes can be long (L), middling (M) or short (S) and the same applies to the right halves. All in all, think of having 6 pages of the flipper book on the left in which the top, middle and bottom snakes are:

LMS, LSM, MLS, MSL, SLM, SML

Each page can be matched with the six options for the right halves, which are also:

LMS, LSM, MLS, MSL, SLM, SML

This means that there are 36 different combinations of left and right halves, and we make snakes that are very long (L on the left and L on the right), very short (S on the left, S on the right) and all possible lengths in between. That's how we are able to suggest so many different instructions.

With each instruction comes a learning opportunity, as the child hears and applies the language of measurement.