Educational Resources Lets Talk Science Challenge participants

General Motors Place

 General Motors Place, Vancouver, British Columbia (Mister Leung [CC BY-SA 2.0], Wikimedia Commons)

STEM in Context

Keeping the Rink on Ice

Let's talk Science

Summary

Learn about the chemistry of ice skating rinks, and the technology & engineering that lets us enjoy them indoors as well as outside.

Do you play ice hockey? Do you skate? Many Canadians would say yes. Even if you said no, you might have seen an ice sport on TV. But have you ever wondered how ice rinks stay frozen?

Did you know?

As of 2019, the Rideau Canal in Ottawa holds the Guinness World Record for longest naturally-frozen ice rink. It is 7.8 kilometres long.

People skating on the Rideau canal
People skating on the Rideau canal (Source: Saffron Blaze [Resolution restricted-by-sa] via Wikimedia Commons).

 

Why does ice float? 

A scientist named John Dalton suggested a theory called atomic theory. Tiny particles called atoms make up all matter. This theory tries to explain how atoms interact with each other. He based the atomic theory on several laws. For example:

  • The Law of Conservation of Mass states that matter can not be created nor destroyed
  • The Law of Constant Composition states that all atoms of a specific element have the same properties and mass

He used this knowledge to determine two things:

  1. Compounds are made up of combinations of two or more types of atoms
  2. A chemical reaction is a rearrangement of atoms

The three most common states of matter are: solids, liquids, and gases. The atoms of most solids are packed together more densely than those of liquids or gases. This is one of the reasons why solids can maintain their shape. On the other hand, liquids and gases can flow, or be poured. 

Most liquids become more dense when they change from a liquid to a solid. Denser materials usually sink when you place them in a less-dense material. For example, if you throw a copper penny into a fountain of water, it will sink. That’s because the penny is denser than the water. 

Can you think of one solid this does not apply to? Hint: Think back to the beginning of this article.
If you said ice, you’re right!

If ice were denser than water, you’d never get to go skating on frozen ponds or lakes. The frozen water would become denser than the liquid water and sink below the surface. Luckily for us, liquid water is most dense at about four degrees Celsius. It becomes less dense when it becomes a frozen solid. This is why ice cubes float when you put them in your drink!

Why does ice float? (2014) by SciShow (2:46 min.).

What are the two types of skating rinks? 

There are two main types of skating rinks. One type has naturally frozen ice from cold temperatures. The Rideau Canal in Ottawa is an example.

The other type has artificially (or mechanically) frozen ice. The hockey and skating rinks you see on TV are examples. Do you have an indoor skating arena in your community? That’s an example of an artificially frozen ice rink, too.
The first artificial ice rink in Canada was built in 1911 in Vancouver, British Columbia. It was built by two brothers, Lester and Frank Patrick. Artificial ice quickly made its way to Toronto in 1912. By 1920, there were four artificial ice rinks in Canada. 

Did you know?

The earliest record of an organized indoor ice hockey game is a game on March 3, 1875 at the indoor Victoria Skating Rink in Montreal, Quebec. Chilly winter temperatures kept the rink and the spectators cold! 

Victoria Skating Rink in Montreal, 1893
Victoria Skating Rink in Montreal, 1893 (Source: William Notman & Son [Public domain] via Wikimedia Commons).

 

How do you keep an ice rink cold?

An artificial ice rink is a complex piece of engineering. There is a lot going on under the ice that we cannot see. 

Underneath the ice or ‘skating surface’ (A) is a large concrete floor. It is also known as the ‘ice slab’ (B).  The ice slab contains hundreds of metres of pipes (C). Brine (salty water) is pumped through these pipes. The concrete floor sits on a layer of insulation (D). This layer allows the ice to expand and contract as necessary. When the ice expands, the atoms move further apart. When the ice contracts, the atoms move closer together. Underneath the layer of insulation is a layer of heated concrete (E). This layer prevents the natural contraction and expansion of the ground from cracking the layers above. The entire structure sits on a sand and gravel base (F). This base contains a groundwater drain (G).

Parts of an artificial ice surface
Parts of an artificial ice surface (© 2019 Let’s Talk Science using an image by sayu_k via iStockphoto).

 

Infographic - Text Version

An artificial ice surface includes A: skating surface; B: concrete floor; C: pipes containing brine; D: insulating layer; E: heated concrete; F: sand and gravel base; and G: groundwater drain.

So how is the ice made? First, the brine in the pipes cools the concrete base. Brine is water with a high amount of salt. Brine can be cooled to lower temperatures without freezing. It keeps the rink’s ice at a cool -4 degrees Celsius. 

Once the concrete base is cold enough, water is added in layers. This action is called flooding. Once the base of ice is completely frozen, the hockey markings are painted on the ice. These markings might include lines, team logos, and advertisements. Finally, the rink is flooded with several more thin layers of water to protect the paint.

But what if that indoor space is used for another sport? Well, you can remove the ice by pumping hot brine through the same pipes that pumped cold brine. This makes the ice covering the concrete base melt.

As you can see, there’s a lot of physical chemistry behind the ice that we skate and play hockey on! 
 

Starting Points

Connecting and Relating
  • Hockey is often considered to be “Canada’s national pastime.” Why do you think hockey has also become so popular around the world, even in warm climates?
  • Do you like to play hockey or skate? Why/why not?
  • Do you prefer to skate on natural or man-made ice? Explain your choice. 
     
Connecting and Relating
  • Hockey is often considered to be “Canada’s national pastime.” Why do you think hockey has also become so popular around the world, even in warm climates?
  • Do you like to play hockey or skate? Why/why not?
  • Do you prefer to skate on natural or man-made ice? Explain your choice. 
     
Relating Science and Technology to Society and the Environment
  • How are science and technology combined to create indoor ice rinks? Explain.
  • How might environmental changes, such as those associated with climate change, have economic and cultural impacts on winter recreational activities? Explain.
  • Besides cooling/refrigeration technology, what other technologies help people play hockey?
     
Relating Science and Technology to Society and the Environment
  • How are science and technology combined to create indoor ice rinks? Explain.
  • How might environmental changes, such as those associated with climate change, have economic and cultural impacts on winter recreational activities? Explain.
  • Besides cooling/refrigeration technology, what other technologies help people play hockey?
     
Exploring Concepts
  • What happens to the density of most liquids as they change from a liquid to a solid? How is water different? 
  • What happens to water molecules when the temperature drops to around 4° C? Why does solid water float? What about its molecular structure makes solid water float? 
  • What law of physics states that matter cannot be created or destroyed? 
  • What is an artificial ice rink? 
  • What is the purpose of brine under the concrete of an artificial ice rink? How does it cool the concrete surface? 
  • Have you watched the Zamboni going around on the ice at your local arena? What task is it doing as it circulates? 
     
Exploring Concepts
  • What happens to the density of most liquids as they change from a liquid to a solid? How is water different? 
  • What happens to water molecules when the temperature drops to around 4° C? Why does solid water float? What about its molecular structure makes solid water float? 
  • What law of physics states that matter cannot be created or destroyed? 
  • What is an artificial ice rink? 
  • What is the purpose of brine under the concrete of an artificial ice rink? How does it cool the concrete surface? 
  • Have you watched the Zamboni going around on the ice at your local arena? What task is it doing as it circulates? 
     
Teaching Suggestions
  • This article can be used to support teaching and learning of Chemistry, Earth & Environment and Math & Physics related to changes of state, states of matter and engineering. Concepts introduced include atomic theory, atoms, matter, Law of Conservation, Law of Composition, compounds, chemical reaction, flow, engineering, brine, expand, contract and flooding.
  • The teacher could introduce this article and generate interest by having a classroom discussion which relates to winter recreational activities.
  • Before reading this article and viewing the embedded video, teachers could also have students complete a Vocabulary Preview learning strategy to engage prior knowledge and introduce new terminology. Ready-to-use Vocabulary Preview reproducibles are available in [Google doc] and [PDF] formats. 
  • After reading the article and watching the video, teachers could have students use a Print-Video Venn Diagram learning strategy to organize and compare the information presented in each of these resources. Ready-to-use Print-Video Venn Diagram reproducibles are available in [Google doc] and [PDF] formats. 
  • To go further after reading the article and watching the video, teachers could lead a discussion about how technologies relating to winter recreation activities have changed over time and may need to further evolve given climate change. Other examples include: snow-making for ski hills, artificial ice surfaces, luge tracks, ski jumps and half pipe constructions for snowboarding, etc.
Teaching Suggestions
  • This article can be used to support teaching and learning of Chemistry, Earth & Environment and Math & Physics related to changes of state, states of matter and engineering. Concepts introduced include atomic theory, atoms, matter, Law of Conservation, Law of Composition, compounds, chemical reaction, flow, engineering, brine, expand, contract and flooding.
  • The teacher could introduce this article and generate interest by having a classroom discussion which relates to winter recreational activities.
  • Before reading this article and viewing the embedded video, teachers could also have students complete a Vocabulary Preview learning strategy to engage prior knowledge and introduce new terminology. Ready-to-use Vocabulary Preview reproducibles are available in [Google doc] and [PDF] formats. 
  • After reading the article and watching the video, teachers could have students use a Print-Video Venn Diagram learning strategy to organize and compare the information presented in each of these resources. Ready-to-use Print-Video Venn Diagram reproducibles are available in [Google doc] and [PDF] formats. 
  • To go further after reading the article and watching the video, teachers could lead a discussion about how technologies relating to winter recreation activities have changed over time and may need to further evolve given climate change. Other examples include: snow-making for ski hills, artificial ice surfaces, luge tracks, ski jumps and half pipe constructions for snowboarding, etc.

Learn more

Boundless Biology: Water 

Informative article by Lumen about the properties of water; contains interactive demonstrations to show how water reacts in response to changes in temperature. Note that this resource was also used as a reference.


Hockey Rink Time-Lapse (2011)

A time-lapse video (2:49 min.) from the Langley Events Centre demonstrating the process of adding ice to an indoor rink


How to build the perfect backyard ice skating rink (2016)

Tips and tricks from Laura Marchand of CBC New on how to create the perfect skating rink in your own backyard!

References

HowStuffWorks.com. (2000, April 1). How do they make the ice at an ice skating rink?

Khan Academy. (2015). Dalton's atomic theory.

Russell, R. (2008, June 25). Solid state. Windows to the Universe.

Schrodt, B. (2015, March 4). Ice skating. The Canadian Encyclopedia.

United States Geological Survey. (n.d.). Water density.