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Blue whale swimming

A blue whale swimming (eco2drew, iStockPhoto)

STEM in Context

Can Whales Really Explode?

Craig White & Let's Talk Science

Summary

When deceased whales wash up on shore, people fear they might explode. Gas laws, decomposition reactions and organic chemistry can help us understand this fear.

WARNING: This resource contains graphic images and links to videos of deceased whales. 

Have you ever noticed that some events seem to capture everyone’s attention? Stories of whales washing up on shore are among these. 

Here’s an example, in April 2014, when nine blue whales were crushed to death in heavy ice off the western coast of Newfoundland and Labrador in April 2014. A few weeks later, a couple of them washed up on shore in neighbouring communities. Within a few days of being reported in the local media, this was a top news story around the world. Why? Because people were concerned about the future of this fascinating endangered species? Not entirely. People were mainly concerned that these whales might explode. 

Why were they worried about this? Let’s look at the chemistry of a dead whale to find out.

Large Blue whale as seen from above off the southern coast of California
Large Blue whale as seen from above off the southern coast of California (Source: D Ramey Logan [CC BY-SA 3.0] via Wikimedia Commons).

Blue whales in danger

The majestic blue whale is the largest animal that has ever existed on Earth. It can be found in the open seas around the world - for now. At the end of the 19th century, there were 180 000 of them. But  industrial whaling through the 20th century brought them and many other whale species to the edge of extinction. The International Whaling Commission banned commercial whaling in 1982. But by then there were few whales left to catch anyway. There are fewer than 250 blue whales in the North Atlantic now. There are 5 000 left overall. Given these numbers, you can imagine why the loss of the nine whales in 2014 was upsetting.  

Can whales explode? 

The idea is that as these huge mammals begin to rot, gases build up inside their bodies. Eventually, these gases might cause the bodies to explode, like an overinflated balloon would. 

**GRAPHIC VIDEO** Dead sperm whale explodes as biologist cuts open carcass (2013) by euronews (1:23 min.).

Did you know?

A blue whale's heart is about the size of a Volkswagen Beetle. The heart beats about 10 times a minute and pumps about 270 litres of blood with each beat.

But is there any scientific evidence supporting this fear?

Well, there is some basis for it.When animals die, their bodies begin to decompose (break down). This happens in two ways. First, the body's own enzymes begin to decompose it. This process is called autolysis. Meanwhile, bacteria decomposes the animal's internal organs and tissues, as well as any remaining food in their gut. This step is called putrefaction.

During the  bloat stage of decomposition, gases like methane (CH4), hydrogen sulphide (H2S) and ammonia (NH3) are produced  You may have heard of dead bodies having a pungent smell. That smell is produced at the bloating stage. It comes  mainly from putrescine (1,4-Butanediamine) and cadaverine (1,5-pentanediamine). These chemicals are produced when amino acids in the body undergo decomposition reactions as part of autolysis.

Let’s look more closely at what is going on with these gases during the bloat stage.

Why are dead whales an “ideal” case of gas laws in action?

As early as the 18th century, scientists observed a relationship between the volume, temperature and pressure of gases inside a container. 

Jacques Charles, a French physicist, noted in 1787 that heating a gas will cause it to expand and take up more space - in other words, have a greater volume. Charles’s Law states that for a given pressure of gas, the volume (V) will be proportional to the temperature (T). 

V ∝ T

Charles’s law comes into play when a whale carcass is warmed in the sun. The increasing temperature causes the gases to expand and increase in volume. Unless these gases have somewhere to go, they will build up inside the dead animal, causing parts of the body to inflate.

Similarly, the volume of a gas is also proportional to that amount of molecules in that gas. This amount is measured in moles (n). This is Avogadro's Law, named for the Italian physicist Amedeo Avogadro. In 1811, he noted that if the temperature and pressure of a gas are kept constant, the volume and amount (moles) of that gas are directly proportional.

V ∝ n

Let's imagine that the whale carcass is lying on the shore for hours. The temperature remains consistent for several hours that day. As the bacteria break down tissue and put more and more molecules of gas into the carcass, the volume will increase. 

Since the whale’s skin and blubber are so thick, the body can only inflate so much. Once it cannot inflate any more, it becomes more like a closed container. That is when Gay-Lussac’s Law kicks in.

Joseph Louis Gay-Lussac was a French chemist and physicist. In 1808, he noted that if you keep the volume of a gas constant (such as in a closed container) and you apply heat, the pressure (P) of the gas will increase. Mathematically, you can say that pressure is proportional to temperature (when volume is kept constant). 

P ∝ T

So, when the temperature goes up but the volume does not, the pressure goes up. Eventually, if the pressure inside a container gets too high, it can cause the container to break and release the built-up gases instantly. In other words, this can cause it to explode.  

Did you know?

An explosion is a rapid expansion of a gas. It is the impact of the shock waves that cause the damage.

Do whales often explode?

Such extreme cases of exploding whales are few and far between. Most scientists agree that whale explosions are unlikely. That’s because a dead whale’s skin will gradually form small tears, which will release some of the built-up gas. Whale explosions are more likely to happen if humans interfere with the corpse. For example, the skin could be punctured by an object. The skin might also break at a weak spot if someone walks on the carcass.

So, if you come upon a dead whale rotting on a beach, you might want to consider staying away. The smell is very persistent (long-lasting)! In a 2001 case of a dead beached whale, people removed the meat. Scientists reported that some tools used to remove the meat still reeked of whale 10 years after the job was done. The danger of a whale explosion may be slim. But you certainly would not want to risk getting sprayed by rotten, liquid tissues!

Did you know?

In 2017 the Royal Ontario Museum (ROM) in Toronto opened an exhibit of the reassembled skeleton of one of the whale carcasses that washed up on the Newfoundland shores in 2014. The exhibit makes use of the skeleton as part of an education program to help people understand a bit more about the world’s largest, and most mysterious, animals.

See the whale virtually using this interactive exhibit walkthrough from the Royal Ontario Museum.
See the whale virtually using this interactive exhibit walkthrough from the Royal Ontario Museum.

 

Starting Points

Connecting and Relating
  • Have you ever come across a dead animal? If so, how did it look and smell?
  • Is there anything you’ve chosen not to buy or do to try to save an endangered species?
     
Connecting and Relating
  • Have you ever come across a dead animal? If so, how did it look and smell?
  • Is there anything you’ve chosen not to buy or do to try to save an endangered species?
     
Relating Science and Technology to Society and the Environment
  • When an issue such as the washing up of dead whales near a town involves different levels of government, what rules and plans should be in place to ensure it is addressed quickly and to the satisfaction of all concerned?
  • Aside from the smell from the rotting carcasses, much of the initial concerns were related to the possibility that the carcasses might explode due to a buildup of gases related to decomposition. What actions could be taken to minimize the potential of this occurring?
     
Relating Science and Technology to Society and the Environment
  • When an issue such as the washing up of dead whales near a town involves different levels of government, what rules and plans should be in place to ensure it is addressed quickly and to the satisfaction of all concerned?
  • Aside from the smell from the rotting carcasses, much of the initial concerns were related to the possibility that the carcasses might explode due to a buildup of gases related to decomposition. What actions could be taken to minimize the potential of this occurring?
     
Exploring Concepts
  • What are the sources of the gases inside of a decaying whale carcass?
  • Which compounds are responsible for the smells produced during decomposition reactions? 
  • How does the gas pressure change inside a sealed container as temperature increases? 
  • Which of the gas laws provide the greatest scientific evidence for the claims that dead whales could explode? Explain your answer.
     
Exploring Concepts
  • What are the sources of the gases inside of a decaying whale carcass?
  • Which compounds are responsible for the smells produced during decomposition reactions? 
  • How does the gas pressure change inside a sealed container as temperature increases? 
  • Which of the gas laws provide the greatest scientific evidence for the claims that dead whales could explode? Explain your answer.
     
Nature of Science/Nature of Technology
  • Scientists have been studying the blue whale for more than 100 years, but still know very little about these huge mammals. Why do you think this is the case? Do you think we will ever know all there is to know about blue whales? Why or why not?
  • What role could technology play in helping scientists learn more about blue whales? Give specific examples to support your answer.
  • Were you surprised to learn that individuals from the ROM were interested in collecting tissue samples from the carcasses in addition to acquiring the skeleton for display at the museum? Do you normally think of scientific research taking place at museums?
     
Nature of Science/Nature of Technology
  • Scientists have been studying the blue whale for more than 100 years, but still know very little about these huge mammals. Why do you think this is the case? Do you think we will ever know all there is to know about blue whales? Why or why not?
  • What role could technology play in helping scientists learn more about blue whales? Give specific examples to support your answer.
  • Were you surprised to learn that individuals from the ROM were interested in collecting tissue samples from the carcasses in addition to acquiring the skeleton for display at the museum? Do you normally think of scientific research taking place at museums?
     
Media Literacy
  • Do you think the media’s initial fixation on the potential that the whales could explode was justified? Should they have focused more on the ecological tragedy that the death of these nine whales actually represented? Explain.
  • What role(s) should reporters play in identifying the parts of a whale-related story they want to tell to their audience? Is there a minimum level of “scientific accuracy” that should be included? Should it be up to the audience to extract the scientific and/or ecological relevance of the story? Explain.
     
Media Literacy
  • Do you think the media’s initial fixation on the potential that the whales could explode was justified? Should they have focused more on the ecological tragedy that the death of these nine whales actually represented? Explain.
  • What role(s) should reporters play in identifying the parts of a whale-related story they want to tell to their audience? Is there a minimum level of “scientific accuracy” that should be included? Should it be up to the audience to extract the scientific and/or ecological relevance of the story? Explain.
     
Teaching Suggestions
  • This article and embedded video can be used in Biology and Chemistry to support teaching and learning related to decomposition reactions and the ideal gas laws. Concepts introduced include bacteria, decompose, methane, ammonia and hydrogen sulfide, volume, temperature, pressure, proportional, explode, Charles Law, Avogadro’s Law and Gay-Lussac’s Law. 
  • Before reading the article, teachers could have students preview the reading vocabulary using a Vocabulary Preview learning strategy. Download ready-to-use reproducibles using the Vocabulary Preview learning strategy in [Google doc] and [PDF] formats. 
  • After reading the article and viewing the video, students could discuss an STSE issue question from the Starting Points using a Think-Discuss-Decide learning strategy. Download ready-to-use reproducibles using the Think-Discuss-Decide learning strategy in [Google doc] and [PDF] formats. 
  • To consolidate and/or assess learning, teachers could have students complete an Exit Slip. Download ready-to-use reproducibles using the Exit Slip learning strategy in [Google doc] and [PDF] formats.
     
Teaching Suggestions
  • This article and embedded video can be used in Biology and Chemistry to support teaching and learning related to decomposition reactions and the ideal gas laws. Concepts introduced include bacteria, decompose, methane, ammonia and hydrogen sulfide, volume, temperature, pressure, proportional, explode, Charles Law, Avogadro’s Law and Gay-Lussac’s Law. 
  • Before reading the article, teachers could have students preview the reading vocabulary using a Vocabulary Preview learning strategy. Download ready-to-use reproducibles using the Vocabulary Preview learning strategy in [Google doc] and [PDF] formats. 
  • After reading the article and viewing the video, students could discuss an STSE issue question from the Starting Points using a Think-Discuss-Decide learning strategy. Download ready-to-use reproducibles using the Think-Discuss-Decide learning strategy in [Google doc] and [PDF] formats. 
  • To consolidate and/or assess learning, teachers could have students complete an Exit Slip. Download ready-to-use reproducibles using the Exit Slip learning strategy in [Google doc] and [PDF] formats.
     

Learn more

Why a dead whale is so important to science (2013)

This article Kate Allen for The Star discusses the scientific uses of a dead whale, and what information we can find out about its life, its health, its environment, and how it died.

References

Bhatia, A. (2014, January 5). What’s the pressure inside an exploding whale? Wired.

Huffington Post Canada. (2014, May 31). Dead blue whale in Newfoundland might not explode: Expert.

Logan, N. (2014, April 28). Dead blue whales washing ashore in western Newfoundland. Global News.

National Oceanic and Atmospheric Administration. (n.d.). Protecting marine life.

Craig White

Craig White is former junior and senior high school biology and chemistry teacher and science curriculum consultant. He has always been interested in science, particularly biology and ecology. As a child Craig was always asking “why?”, taking things apart to see how they worked (sometimes getting them back together), and exploring his local environment. He teaches undergraduate science education courses where one of his academic interests is how we address the Nature of Science in classrooms to ensure students develop a true understanding of what science “is”, and the role science plays in our lives.