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illustration of a hydrogen car

Hydrogen car (Beboy_ltd, iStockphoto)

STEM in Context

The History and Uses of Hydrogen

Aaron Granger & Let's Talk Science

Summary

Hydrogen’s tendency towards combustion is what makes it both a dangerous chemical element and a useful energy source.

Name: Hydrogen

Symbol: H

Atomic Number: 1

Relative Atomic Mass: 1.008

Category: Reactive nonmetal

Appearance: colourless, odorless gas

Hydrogen is the simplest and most common of the chemical elements, which are the building blocks of all matter. Other atoms are made up of protons, neutrons, and electrons. But hydrogen has only one electron and one proton. It's also the most abundant element. In fact, hydrogen makes up about three quarters of all matter in the universe.

Did you know?

The United States produces around 85 million cubic metres of hydrogen every year. That’s equivalent to more than 50 times the volume of the Rogers Centre in Toronto!

Hydrogen is a colourless, odourless non-metal. In its most common form, it’s extremely combustible. In other words, it has a tendency to burst into flame. This tendency makes hydrogen both a very dangerous and a very useful resource.

When was hydrogen discovered?

Hydrogen was first discovered in 1671 by British scientist Robert Boyle. He had been experimenting with different metals by dipping them in acid. When a pure metal is placed in acid, a type of reaction called a single-displacement reaction takes place. For example, adding a piece of potassium (K) to a solution of hydrochloric acid (HCl) causes the following reaction to occur:
 

2K + 2HCl → 2KCl + H2

Potassium metal reacting with concentrated hydrochloric acid (2014) by Jeremy Wolf

The solid potassium metal reacts with the acid to form a salt called potassium chloride. Meanwhile, the leftover hydrogen atoms combine to form hydrogen gas.  

In a 1776 paper, a British scientist named Henry Cavendish confirmed that hydrogen is a distinct element. Both Boyle and Cavendish noticed that hydrogen gas is very flammable. Specifically, it quickly and violently undergoes a combustion reaction with oxygen.

2H2 + O2 → 2H2O (+ Heat)

The reaction takes molecules of hydrogen and oxygen and combines them together to form H2O (water). This reaction is exothermic. That means it generates heat energy - in other words, fire. Other scientists would later discover that hydrogen provides the fuel for the nuclear fusion reactions that happen inside stars. Those fusion reactions generate all of the light and heat that the Sun and other stars produce.

Did you know?

Hydrogen melts at 14° above absolute zero (14° Kelvin or -259 C

What has hydrogen been used for in the past?

Along with its flammability, Boyle and Cavendish also observed that hydrogen is less dense (lighter) than air. Hydrogen is great at lifting things like balloons. In this way, it’s similar to the second simplest element, helium. In fact, hydrogen is even better at lifting things than helium. So it was only a matter of time before people started designing hydrogen-filled balloons for transportation. By the early 1900s, large airships that used hydrogen as their lifting gas had become a popular form of air travel.

However, the hydrogen-filled airship craze didn’t last long. In 1937, tragedy struck in the United States. The German airship Hindenburg caught fire and exploded at Lakehurst, New Jersey, killing 36 people. 

Airship designers knew that hydrogen is flammable and that helium was a safer choice. However, helium was rare and expensive. So they went with the cheaper but less safe option. After the Hindenburg disaster, hydrogen was quickly abandoned as a lifting gas. At the same time, airplanes were becoming more common.

Explosion of the zeppelin Hindenburg
The explosion of the zeppelin Hindenburg demonstrates the combustibility of hydrogen (Gus Pasquerella via Wikimedia Commons).

What has hydrogen been used for more recently?

You’ve probably seen videos of a Space Shuttle launch from the Kennedy Space Center or docking at the International Space Station. That program was cancelled in 2011. But until then, the Shuttle was the main way for NASA astronauts to get into space. Ever wonder what powered those impossibly huge engines? It was hydrogen!

The Space Shuttle’s main engine was powered by burning liquid hydrogen and liquid oxygen. How much power does burning hydrogen provide? So much that it’s hard to imagine! Three Space Shuttle engines working together put out roughly the same amount of energy as 120 railroad locomotives. 
 
NASA engineers also understood just how dangerous hydrogen could be. However, they decided they could take advantage of all that raw power as long as they were very careful.

Testing a hydrogen rocket
Testing a J-2X hydrogen-fuelled rocket engine for possible use on NASA’s Space Launch System (SLS). This rocket is designed to send astronauts to the Moon and Mars. Hydrogen burns very cleanly, and the flame is almost invisible (Source: NASA [Public domain] via ResearchGate).

Lately, people have been increasingly interested in reducing their impact on the environment. One way to do this is to stop burning fuel to power cars. There is a lot of interest in developing hydrogen fuel cell-powered cars. The nice thing about using hydrogen to fuel cars is that, unlike with gasoline, the waste product isn't a greenhouse gas - it’s water!

Did you know?

As of 2018, there are three hydrogen-powered cars in production. Honda, Hyundai, and Toyota are each producing a hydrogen-powered car.

How does a fuel cell work? (2011) by Naked Science Scrapbook (4:01 min.).

Unlike the Hindenburg, hydrogen-powered cars don’t need to be super light like balloons so the fuel is compressed and stored in very tough tanks to prevent leaks. The best solution would be to store the fuel as a solid rather than as a gas. The material can still burn as a result of an accident. However, it would be unlikely to explode. The risk of fire in accidents is about the same as with a gasoline-powered car.

But one of the main problems with using hydrogen as a fuel source for cars is storage. Hydrogen has more energy than gasoline by weight, but it has less energy by volume. That means that you need a pretty big tank of hydrogen gas to drive your car a reasonable distance before refuelling. The gas tanks of most cars are too small to store enough hydrogen gas to get around town! 

Scientists have been looking into converting the hydrogen from a gas to a solid. The reason for this is low energy density. When hydrogen is absorbed into a solid chemical, it can gain a higher energy density. Academic, industry, and government researchers are all looking into this innovative way of bringing hydrogen to the forefront of the energy economy.

Human understanding of hydrogen has come a long way since its discovery in 1671. It’s been used to lift zeppelins and get people into space. And it just might be the power source that fuels the cars of tomorrow!
 

Starting Points

Connecting and Relating
  • When you hear the word hydrogen, what does it make you think about?  
  • If you were buying a new car, would you consider purchasing a hydrogen fuel cell-powered vehicle? Why or why not? 
     
Connecting and Relating
  • When you hear the word hydrogen, what does it make you think about?  
  • If you were buying a new car, would you consider purchasing a hydrogen fuel cell-powered vehicle? Why or why not? 
     
Relating Science and Technology to Society and the Environment
  • Why it is important to research and develop alternative fuels?
  • What are some of the ways that governments try to limit the amount of greenhouse gases that are released into the atmosphere? 
  • Should governments provide incentives to manufacturers and consumers to increase the number of hydrogen fuel cell cars being used? Explain.
  • The initial costs of hydrogen fuel cars will be in the luxury car price range. Do you think this will have a negative effect on sales? Explain.
     
Relating Science and Technology to Society and the Environment
  • Why it is important to research and develop alternative fuels?
  • What are some of the ways that governments try to limit the amount of greenhouse gases that are released into the atmosphere? 
  • Should governments provide incentives to manufacturers and consumers to increase the number of hydrogen fuel cell cars being used? Explain.
  • The initial costs of hydrogen fuel cars will be in the luxury car price range. Do you think this will have a negative effect on sales? Explain.
     
Exploring Concepts
  • What other forms of alternative fuels are being researched?
  • How does the hydrogen-fuel cell produce energy?
  • According to the article, solid hydrogen might burn as a result of an accident, but would be unlikely to explode. Explain.
  • Identify other single-displacement reactions in which hydrogen gas is produced.
     
Exploring Concepts
  • What other forms of alternative fuels are being researched?
  • How does the hydrogen-fuel cell produce energy?
  • According to the article, solid hydrogen might burn as a result of an accident, but would be unlikely to explode. Explain.
  • Identify other single-displacement reactions in which hydrogen gas is produced.
     
Nature of Science/Nature of Technology
  • How have our opinions, of what is considered to be a “good” fuel source, changed over time?
  • What role does scientific research play in the production of technology that may help reduce greenhouse gas emissions?
     
Nature of Science/Nature of Technology
  • How have our opinions, of what is considered to be a “good” fuel source, changed over time?
  • What role does scientific research play in the production of technology that may help reduce greenhouse gas emissions?
     
Media Literacy
  • What are some strategies that advertisers use when trying to sell fuel-efficient cars?
  • Do media reports of advances in alternative energy create expectations for products that may not materialize in the near future? Explain.
  • How do you think an advertising campaign for a hydrogen-powered car would differ from that of a regular car?
  • Create a media campaign for a hydrogen-powered car.
     
Media Literacy
  • What are some strategies that advertisers use when trying to sell fuel-efficient cars?
  • Do media reports of advances in alternative energy create expectations for products that may not materialize in the near future? Explain.
  • How do you think an advertising campaign for a hydrogen-powered car would differ from that of a regular car?
  • Create a media campaign for a hydrogen-powered car.
     
Teaching Suggestions
  • This article and embedded video can be used for Chemistry teaching and learning related to chemical elements, combustion, endothermic & exothermic reactions, fuel cells and energy sources. Concepts introduced include, electrons, protons, non-metals, combustibility, acids, single-displacement reactions, potassium chloride, combustion reactions, exothermic reactions, heat energy, helium, airships, the Space Shuttle, hydrogen fuel cells and energy density.
  • Before reading this article, teachers could provide students with a Vocabulary Preview to engage prior knowledge and introduce new terminology.  Ready-to-use reproducibles using the Vocabulary Preview learning strategy for this article are available in [Google doc] and [PDF] formats.
  • After reading the article and watching the embedded video, students could explore the pros and cons of hydrogen-powered vehicles using a Pros & Cons organizer. Ready-to-use reproducibles using the Pros & Cons Organizer learning strategy for this article are available in [Google doc] and [PDF] formats.
Teaching Suggestions
  • This article and embedded video can be used for Chemistry teaching and learning related to chemical elements, combustion, endothermic & exothermic reactions, fuel cells and energy sources. Concepts introduced include, electrons, protons, non-metals, combustibility, acids, single-displacement reactions, potassium chloride, combustion reactions, exothermic reactions, heat energy, helium, airships, the Space Shuttle, hydrogen fuel cells and energy density.
  • Before reading this article, teachers could provide students with a Vocabulary Preview to engage prior knowledge and introduce new terminology.  Ready-to-use reproducibles using the Vocabulary Preview learning strategy for this article are available in [Google doc] and [PDF] formats.
  • After reading the article and watching the embedded video, students could explore the pros and cons of hydrogen-powered vehicles using a Pros & Cons organizer. Ready-to-use reproducibles using the Pros & Cons Organizer learning strategy for this article are available in [Google doc] and [PDF] formats.

Learn more

Fuel Cell vehicles

The US Department of Energy provides information on how (hydrogen) fuel cell cars compared to conventional cars and some of the pluses and minuses

References

Aerojet Rocketdyne. (2019). RS-25 engine.

Barbir, F. (n.d.). Safety issues of hydrogen in vehicles. University of Illinois.

Cavendish, H. (1766). Three papers, containing experiments on factitious air. Philosophical Transactions of the Royal Society. 56,141-184. DOI: 10.1098/rstl.1766.0019

JLab Science Education. (n.d.). It's elemental - The element hydrogen.

Los Alamos National Laboratory. (n.d.). Periodic table of elements.

Royal Society of Chemistry. (n.d.). Hydrogen - Element information, properties and uses.

Aaron Granger

Aaron has a PhD in chemistry. He's done research in academia and industry, but prefers teaching science to upcoming students. He loves getting people excited about science by doing hands-on weekend science projects.