The giant soup can of Hornby Island

Figure 1: The giant soup can of Hornby Island

When trying to answer the question on the actual size of the painted water tank in the photo, it is important to keep in mind that the water tank has the exact same proportions of a Campbell’s Soup can. We can use the dimensions of a can of Campbell’s soup and scale up to estimate the size of the water tank using the bicycle as a reference. 

Figure 2: A can of Campbell’s Vegetable Soup

From Figure 2, the Campbell vegetable soup I will be measuring from has 284mL. For this exercise, I will assume the volume of the can is as the equation for the volume of a cylinder: pi*r^2*h. Taking measurements of our can, I find that it has a diameter of 6.6cm (radius is 3.3cm) and height of 10.2cm. Entering these in our equation for the volume of a cylinder, I get 348.96cm³.

I googled ‘dimensions of a bicycle’ for diagrams and found that most bikes had a length of around 990mm (99cm) to 1080mm (108cm) as the distance between the centre of the rear wheel to hub of front wheel. Bicycle wheels have a diameter ranging between 419mm (41.9cm) to 633mm (63.3cm) according to PandaEbikes. If this bike had a 520mm diameter (52cm) wheel, then the radius would be 260mm (26cm). For this estimate, I will take the length of the bike to be 108cm + 52cm = 160cm (adding 26cm to rear wheel radius and 26cm to front wheel radius). 

Figure 3: Example of bike dimension found on google images

I then imagined how many bikes would fit length-ways across our water tank. Figure 4 shows that approximately 3.5 bikes fit lengthways, giving our height of the water tank; h = (3.5)(160) = 560cm. Comparing this to the height of the Campbells soup can of 10.2cm, this is 54.9 times larger. I can then estimate the radius of the water tank to also be 54.9 times larger, which equates to 181.17cm. Therefore the volume of water that the water tank can hold is pi*(181.17)^2(560) = 57744479.14cm³ or in terms of liquids to be 57744479.14mL or 57744.48 litres of water.  

Figure 4: Estimating height of water tank

An extension I have for an activity similar to this for secondary students, is to estimate the volume of places such as how much water could fill up the classroom, or ask students to scale up objects such as their phones and estimate the surface area it would cover. 

 

Source:

Pandaebikes. Ebike-motor-wheel-rim-size-guide. Accessed November 9, 2020 from https://www.pandaebikes.com/what-is-my-wheel-size/ebike-motor-wheel-rim-size-guide/.