3 iPad apps for volume and surface area investigations


This week, Grade 5 began a unit on Volume, Capacity and Surface Area. On a weekly basis, I take combined groups from the 4 grades consisting of the higher achievers, while the classroom teachers concentrate on the mainstream group and students needing more individual instruction to achieve success. I made a conscious decision this week to focus on using iPads with my group to explore both volume/capacity as well as surface area.

I chose 3 apps to assist me in this learning experience – Think 3D ( free version) and Skitch, which are both free apps and Numbers ($9.99- $4.50 through the Volume Purchasing Program if 20 or more bought). Note: you could substitute the currently free CloudOn app, which is basically a server based Office app, or Google Spreadsheets, a free component of Google Docs/Google Apps for Education.

In the past I would have run this lesson using a limited number of connecting blocks and would have asked the students to record their observations in their exercise books. In using the iPads and the selected apps, I wanted to trial how this type of investigation could be enhanced and improved upon by using technology rather than traditional tools.


The lesson began with the following premise. Each pair of students ( didn’t have enough iPads for 1:1; would probably work in pairs regardless to encourage collaboration and discussion) was to create a cuboid or rectangular prism with a volume of 72 cubes using Think 3D. In the past, students would have used a limited supply of blocks and would only have had enough to make one model. Using the iPad app, they were able to explore multiple ways of making a 72 cube prism with a limitless supply of cubes with a simple touch of the screen adding or deleting  a cube to the prism each time.

Another advantage is that, while there are many benefits in physically seeing and touching a real 3D object rather than a 2D representation of one on a screen, the ability to rotate the prisms on the iPad to view the different surfaces with a simple swipe made for easy investigation and no chance of the object falling apart and needing to rebuild, thus saving time for more analysis.

Using Reflection on my Macbook ( also available for PCs), the children were able to mirror their iPad screens on our interactive whiteboard and share all of the possible prisms and cuboids. This allowed for easy comparison and discussion without having to move our models around as we would have in the past.

The next step was to save the models as images in the Photo library on the iPad so that we could import them into Skitch, (an annotation app linked to Evernote.) As you can see from the image below, the students were able to clearly label the dimensions of their prisms and record surface area measurements as well. The use of this app enables easy collection of data for assessment rather than the rather difficult alternative of taking photos with a camera and writing notes about each photo. It also makes it easy for the children themselves to keep records of their work and thinking, an improvement on the lesson for both teacher and student. They were also able to swipe back to Think 3D to manipulate the prism to investigate the dimensions closely during the annotation stage.


We then opened up Numbers to systematically record and calculate the measurements using spreadsheet formulas. Being capable students, they already knew how to use the L X W for area and L X W X H for volume formulas. I wanted to skill them up in using spreadsheet formulas to make quick calculations so that more time could be used for analysing the measurement data and the 3D models.

The spreadsheet was laid out so all possible dimension combinations discovered by the students were recorded. We then inputted a volume formula to verify each prism had a volume of 72 cubes. We then used formulas of our own creation to calculate the surface area of each prism. Once one formula was created, we were able to copy and paste that formula for each prism to calculate each prism’s surface area. Once we had all of the volumes and surface areas, combined with the 3D models, students were then able to make informed conjectures, observations and proofs about why certain prisms of the  same volume had varying surface areas.

While I am not saying I haven’t taught this lesson successfully in the past, using these apps and the iPad allowed for more direct and focused engagement from all students. Previously, the recording of data would have been a whole class event, which I always feel has the potential for disengagement as children watch others do the work. Having limited resources in terms of blocks, early problem solvers are left waiting for others. With the use of Think 3D, they were able to continue on with their own investigations rather than waiting for another pair to make an alternative model.

With today’s lesson, the children were actively involved in all aspects. They had opportunities to explore as many options as they had time for, they inputted all mesurement data, they annotated all of their images, which enabled them to consolidate and record their thinking more efficiently. The technology used also enabled them to save a permanent record of all the work they did today, whereas in the past, it was lost once the cubes were packed up. I  think this is a good example of how technology, and the iPad in particular, can be used for greater engagement and deeper thinking in Mathematics. Yes, all of the steps in the lessons could have been done without tech or iPad specifically, but I don’t think it is as effective.