Have you ever seen the word “pasteurized” on a carton of milk? You might think it means something about pastures – big grassy fields where animals graze. That’s usually how people pronounce it. But while it’s nice to think of the cows that gave us the milk sunning themselves in grassy pastures, the word actually refers to something that happens after the milk is out of the cow. Before milk goes into cartons and then on to the store, it undergoes pasteurization. The milk is heated to a specific temperature in order to kill any harmful microorganisms, or germs, that might make you sick. It has nothing to do with grassy fields! Instead, it’s named after the man who invented the process: Louis Pasteur.  

Educational Background of Louis Pasteur

Louis Pasteur’s background gave no hint that he would become a great scientist later in life. Born in 1822 in Dole, France, he came from a long line of leather tanners. His family was poor, and Louis wasn’t even that interested in school as a child. He preferred fishing and drawing. He actually became very good at drawing portraits of his friends and family using pastels and pencil.

Things began to change when Louis went off to college. He began to study hard, but still struggled. His grades in chemistry – a subject he would later do important work in– were especially bad. He wanted to go to the prestigious Ecole Normale Superieure in Paris, but had to take the entrance exam twice! But even though he had setbacks, his hard work and dedication paid off. 

While he was working to try to get into the Ecole Normale, Louis began attending lectures by a famous chemist, and decided that he wanted to be a chemist too. So, when he finally went to the Ecole Normale, that’s what he studied. After he got his doctoral degree, he got a job at the University of Strasbourg, teaching and doing research in the structure of chemical crystals. 

He also met his wife, Marie, there. She was the daughter of the head of the university. At first, she wasn’t so sure about this serious, somewhat shy man. But after getting to know him better, she fell in love too, and they married. She would support him throughout their lives together, helping in the lab and with his papers. 

Louis Pasteur’s Early Works

Even though Louis started out as a chemist, his most important work is in microbiology, or the study of organisms so small, you need a microscope to see them. This shift happened almost by accident, but as Louis himself reminded people, “In the fields of observation, chance favors the prepared mind.” In 1854, he got a new job at a university in northern France. While there, the owner of a factory came to him with a problem. His factory fermented sugar beets to make alcohol, but sometimes he ended up with a spoiled, sour elixir, instead of alcohol.  

At this time, scientists didn’t know how fermentation worked. Some thought it was just chemicals rearranging themselves spontaneously under the right conditions. Most people just knew that when you left crushed grapes or soggy grain in a covered container for long enough, you got wine or beer. Louis wasn’t satisfied with those answers though, and set about trying to solve the mystery. He got samples of the good alcohol and the sour substance and put them under his microscope. 

What do you think he saw?

He saw different kinds of microorganisms swimming around in them! The alcohol samples had yeast, which is a microscopic type of fungus. The sour stuff had bacteria, which is a completely different kind of microorganism! Both types float around in the air, but Louis was the first to realize that the yeast settled in containers of grapes or mashed grain and caused fermentation. Those tiny yeast ate up the sugars in the beets, used it to make energy, then got rid of the uhhh…waste that they didn’t need. That waste was the alcohol.

Studies in Microorganisms

Louis was hooked. He went on to study the microorganisms in wine and beer, finding new ways to make sure they weren’t contaminated by tiny critters that would spoil them. But he wasn’t just interested in making beverages safer, although this was very important for people’s health and the French economy. Louis wanted to know more about how these tiny microorganisms lived. If so many scientists were wrong about fermentation, what other discoveries were waiting to be made?

One idea that didn’t make much sense to Louis was “spontaneous generation.” Spontaneous generation was the idea that some living creatures just arose from nonliving things. Rotting meat made flies, some people thought, because they’d seen fly larvae on rotting meat. Louis thought that flies must be laying tiny eggs in the meat. He suspected that microorganisms, like the yeast in beer and wine, actually float around in the air, settling on things and, if the conditions are right, growing and multiplying.

Louis devised an ingenious way to demonstrate that living things didn’t just spring fully-formed from non-living things. He designed a bottle with a long, skinny neck that curved downward like the top of the letter S, opening toward the ground. He then boiled a broth, killing any microorganisms that were already in it. He poured some of the broth into the S-neck bottles, and some into bottles with necks that opened upwards, toward the sky. 

Then he waited. After a few weeks, the bottles with the S-necks hadn’t really changed. But the ones with upward-facing necks had become cloudy. Looking at the liquid under a microscope confirmed that microorganisms had landed from the air and grown in it. But, microorganisms couldn’t land in the S-neck bottles, so that liquid stayed clear!

With all these accomplishments and discoveries to his name, you might be wondering, what else can one scientist do? A lot, it turns out! Louis wanted to study how microorganisms might be involved in causing diseases, and maybe even find ways to prevent or cure those diseases.  Sadly, he was motivated by events in his own life: three of his daughters passed away from typhoid fever when they were young. He started studying two diseases caused by bacteria: chicken cholera and anthrax. 

Chicken cholera is not a serious disease for humans, but is deadly to chickens, which you might have guessed from the name. Louis developed a vaccine for it almost by accident, but as with his study of microorganisms in alcohol, he was prepared to take advantage. Before going on vacation Louis gave an assistant specific instructions for how to infect some chickens with the bacteria they had been growing. But the assistant waited too long, and the cholera bacteria dried up. Lucky chickens!

But Louis didn’t think of himself as unlucky. Instead, he decided to give the chickens a dose of the dried-up, mostly-dead bacteria. These chickens got a little sick, but soon recovered. Later, Louis injected those same chickens with fresh, living cholera bacteria. Louis suspected that the first dose of mostly-dead cholera bacteria might actually protect the chickens from the living bacteria. He was right! The chickens didn’t get sick again!

Next, Louis heard about a vaccine for anthrax that a veterinarian named Jean Jaques Henri Toussaint had invented. Anthrax bacteria was deadly to both farm animals and people. He tested Toussaint’s vaccine, and it worked. In an unfair twist, Louis got credit for creating the vaccine, because his test was more widely covered in newspapers at the time. Sadly, Toussaint died only a few years later.

But Louis wasn’t done working on vaccines. The next disease he studied was truly terrifying: rabies. Rabies is a virus that causes animals, and unfortunate humans they might bite, to get a high fever, behave aggressively, fear water, and eventually die. There was no cure. Louis got to work, trying to develop a weaker version of the disease that could be used to make a vaccine. He tested it out on dogs. It seemed to work, but Louis wanted more time to experiment. 

But the experiment was about to speed up. One summer day in 1885, a mother burst into the lab, gripping the hand of her nine year old son. Both were crying and distraught. The boy, Joseph Meister, had been bitten 14 times by a rabid dog. Louis was worried because he had never tried his vaccine on a human. But without help, Joseph would die. Louis had to try. Just as they had done with the dogs, Louis and his assistants injected Joseph with the vaccine several times over the course of weeks. Louis and the boy’s mother spent this time worrying and waiting. It can take weeks or months for a person to get sick with rabies after they’ve been bitten, so they wouldn’t know if the vaccine had worked for some time. 

But time passed, and Joseph stayed healthy! He went back to school and playing outdoors, though I wouldn’t be surprised if he was afraid of dogs after that. People all over the world heard about the new rabies vaccine, and people came from miles away to receive it if they’d been bitten. Today, almost all pet dogs and cats get the rabies vaccine, though humans usually only get it if they’ve been bitten by a wild animal. Louis’s vaccine saved countless lives.

Louis Pasteur always wanted to use his work to serve others. Thanks to his work, we know a lot more about how microorganisms work, how they cause disease, and how to keep from getting sick from them. But Louis knew that wanting to do good wasn’t the same as actually doing it. He worked tirelessly, sometimes pacing the room late at night while he thought through a problem. He was careful and methodical in his work, trying to be sure he’d gotten it right, before he made any exciting announcements. But he also knew when to take advantage of an opportunity. If he didn’t, he never would have studied the yeast in fermented drinks, or how to make vaccines from weakened germs. He never would have saved Joseph Meister’s life with his rabies vaccine. Your milk wouldn’t be as safe to drink. So next time you notice something unexpected, or find something didn’t work the way you thought, think of Louis Pasteur, and keep examining it. Look at it carefully. You might discover something amazing!

Sources

Curtis, Robert H. (1993) Great Lives: Medicine. Macmillan, New York.

Dickman, Nancy (2016) Louis Pasteur: Germ Destroyer. Gareth Stevens Publishing, New York.

https://www.khanacademy.org/science/ap-biology/cellular-energetics/cellular-respiration-ap/a/fermentation-and-anaerobic-respiration

https://www.nature.com/articles/d42859-020-00008-5

https://pubmed.ncbi.nlm.nih.gov/20527335/

http://thispodcastwillkillyou.com/wp-content/uploads/2021/10/TPWKY-Episode-82-Anthrax.pdf

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Take a look around the room you’re in right now…

Do you see many things that you or a family member made with their own hands? Maybe you have a special baby blanket that someone knitted for you, or a few art projects hanging on the wall, but I’m guessing that most of the things in the room were made far away in factories. 

250 years ago, things would have been very different. Most of the items in your house would have been made by someone you knew. Either you or a family member would make them, or you would have traded or bought them from someone in your community who made them. Other things might have been handed down from your grandparents.

Back then, people had to know how to do many things to survive and keep themselves comfortable. A man would have a trade, but would also be able to grow food, chop wood, and build and fix things in his house. Women knew how to cook, sew, spin, and weave cloth, keep a garden, and churn butter. A few might have traded too. Children would also do a variety of jobs and chores to keep the household or farm going. A boy would become an apprentice to learn a trade around 13. Most labor was done by people, not machines. The machines that did exist were powered by livestock, like horses and oxen. 

Industrial Revolution

All this would change with the Industrial Revolution. No single invention or person set off the industrial revolution. In fact, the industrial revolution was happening for about 100 years. It’s also important to know that in this time period, these changes started in England, and then spread to the United States and Europe, so that is where we’ll focus in this episode. There were several important inventions and ideas that would change the world and make it look a lot more like it does now. These innovations would drastically change how people worked, and how they bought and made things. Three big types of things happened:

1. New machines were invented.
2. People figured out how to power those machines. At first, they used steam power, then later electricity, oil, and gas.
3. People started building factories, where they could make large quantities of products in one place, instead of having individuals make things in small workshops

But why did people suddenly start inventing all these new machines and ways of doing things? One reason was a population explosion in Britain in the 18th century. All the new babies being born meant that people needed more clothing, and they didn’t want to pay too much. The tradespeople who made cloth and clothing couldn’t keep up. So some of these tradespeople started to invent ways to make more thread and cloth in less time and with less work. They invented machines for spinning thread and weaving cloth.

Water Power

At first, the factories that did this spinning and weaving were located next to rivers. The river’s current would turn a giant wheel, which would power the moving parts of the machinery inside. As you can imagine, this could be inconvenient if you wanted to set up a factory but didn’t live near a river. It wouldn’t be long before people began to invent new ways of powering machines, so they wouldn’t need to be near rivers anymore. You’ve probably heard of engines, like the ones in cars and planes. But did you know that an engine is any machine that generates energy? Engines were about to change how people made things once more.

Steam Power

The first new source of power was the steam engine. When you think of a steam engine, you probably imagine a big train with smoke pouring out of its stack. That is one type of steam engine, but the first steam engines didn’t power trains. They were used in mines. Miners have to dig deep into the earth to find minerals or metals, and often, the mines would flood. The first steam engines were used to pump water out of mines, but they weren’t very powerful. 

A man named James Watt would change that. In 1765, he redesigned the steam engine to be much more powerful and efficient. This made it better at pumping water, but also made it useful for running machinery in factories. And of course, it paved the way for the train steam engine, which would make travel easier and faster!

Steam engines required wood or coal to operate. I won’t go into the details, but wood or coal would be burned in order to heat water to create steam, which in turn powered the machinery. Burning wood and coal, of course, creates a lot of smoke, and this caused a lot of air pollution. In areas with many factories, such as around Birmingham, England, tree trunks even turned black from the smoke! 

Eli Whitney

So far, all the inventions we’ve talked about were created in England, but inventiveness was spreading! In 1793, a tinkerer named Eli Whitney would invent the machine that would bring the industrial revolution to America. Whitney had traveled to South Carolina to work as a tutor. But, while he was visiting a friend’s plantation, he learned about a big problem that southern farmers had with their cotton crops: the white fluff was full of sticky seeds that had to be picked out by hand. It took one person a full day to pick the seeds out of one pound of cotton! 

In about 10 days, Whitney invented the cotton gin. The “gin” part is short for “engine.” It used a system of combs, rollers, and wire sieves to pull the seeds out of the fluff. One person operated the machine with a simple crank. The cotton gin made the work much faster, which meant farmers could make more money by growing cotton.

Unfortunately, many cotton growers decided to buy more slaves in order to process even more cotton using the new machine. Whitney didn’t expect this. He thought his machine would actually reduce slavery, since it did the same job that enslaved people had been doing. But instead, growers just decided to grow even more cotton. That meant more enslaved humans picking the cotton and operating the gins. 

The industrial revolution had some other unexpected results when it came to workers. Many tradespeople didn’t want things to change. They thought that the new machines would take away their work, and then they wouldn’t be able to support themselves. Some got so angry that they attacked the new factories and mills, smashing machinery and even burning some factories to the ground!

Child Labor

Once it became clear that the factories weren’t going away, many of these skilled workers didn’t want to work in them. So, instead of hiring grown-ups, some factory owners began to hire children instead. Children, some as young as five years old, went to work in factories for long, exhausting days. Factory owners paid them only a fraction of what they paid adults for dangerous, difficult work. It would be a long time before countries made laws saying that children need to be allowed to go to school and play, instead of working in factories for very little pay.

Some people, though, welcomed the opportunity to work in a factory. The factories also hired women. In the old system, most women didn’t learn a trade. They got married and did household and farm work to support the family. Working in factories allowed young women in some areas to earn and control their own money, instead of having to get married at a young age and rely on their husbands.

Before the industrial revolution, most people lived in rural areas or small towns, where they could grow food for themselves. As more and more products were made in factories, instead of small workshops, many more people moved from rural areas and farms into the cities where they could work in factories. Cities became crowded and dirty, with many people living in poverty. 

What were working conditions like during the Industrial Revolution?

The factories themselves were also crowded and dirty. On top of that, they were often poorly lit and stuffy. Some were so loud that workers went deaf. Workers were often exposed to materials that could make them sick, and machines that could injure them.  Unlike independent tradespeople, factory workers did the same task over and over again, and they didn’t have much say in how or when they worked. Workdays were long–often 12 hours–and many bosses were very strict. They would only allow workers a few short breaks throughout the day. Many would take away pay if a worker made a mistake or didn’t work fast enough.

The industrial revolution changed just about everything about how people lived and worked.  People went from being skilled craftspeople who had a lot of control over their work, to factory laborers forced to endure harsh, unfair conditions. It changed where people live, as they moved from rural areas to cities. This trend has continued all the way until today, as cities are still growing.

But even though it resulted in pollution, bad working conditions, and child labor, the industrial revolution also made many other innovations possible. We’ve only had time to talk about a few of the innovations of the early industrial revolution, but it wasn’t all about steam power and cloth manufacturing. By the late nineteenth and early twentieth century, we had cars, airplanes, and refrigeration. 

People also started to work together in new ways. Workers began to talk to each other. They formed labor unions and insisted that their bosses make factories safer. The idea of the weekend was born, and laws were passed to require better working conditions. Child labor was eventually outlawed. 

Conclusion

It’s important to remember that events in history often have good and bad consequences. We have to look at both in order to understand the full impact they had on the world. Knowing about the unintended consequences of past events can help us avoid similar results in the future. When we see things in the world today that might cause people, animals, or the planet to suffer, we can ask what we can do to help make things better. That way, we can keep building a better future, bit by bit.

Sources

https://www.britannica.com/summary/Industrial-Revolution-Key-Facts

https://www.eliwhitney.org/7/museum/about-eli-whitney/inventor

https://www.loc.gov/collections/america-at-work-and-leisure-1894-to-1915/articles-and-essays/america-at-work/

  March 14: Eli Whitney Patents the Machine He Thought Would Help End Slavery. Office of the State Historian, Connecticut. https://todayincthistory.com/2020/03/14/march-14-eli-whitney-patents-the-cotton-gin-2/ 

Major, Kenneth (1980) Pre-industrial Sources of Power: Muscle Power. History Today, 30:3.

https://cpb-us-w2.wpmucdn.com/voices.uchicago.edu/dist/a/1299/files/2019/07/sti2014_the-pre-industrial-sources-of-power_-muscle-power-_-history-today.pdf

Mooney, Carla (2011) The Industrial Revolution: Investigate How Science and Technology Changed the World. Nomad Press, Vermont.

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Imagine you are in Europe. The year is 1895 and you live in Poland. Life is changing quickly at this time. Many people have been moving to cities for work or to America to start a new life. But you are a happy child, loving life with your four older siblings. Your father is a math and science teacher and from him, you have come to love math and science as well. However, you do not yet realize that one day you will become one of the most famous scientists in the world. You are Marie Curie.

Marie Curie was born in Warsaw, Poland in 1867. She was the youngest daughter of five children. When she was born, her name was Marie Sklodowska. She changed her name to Marie Curie later when she got married.

Marie had a happy child and she became interested in science at a young age. She was very smart and got good grades in school. Sadly when Marie was only 10, her mother died. She had become sick with tuberculosis. 

Marie was raised by her father and became more and more interested in math and physics. Physics is the branch of science concerned with the nature and properties of matter and energy. Even though Marie got the top grades in her high school, she was not able to go to university when she graduated. The reason was because the university in Warsaw was a men’s-only university at the time.

Marie was very disappointed, but she continued to learn about the subjects she loved however she could. One way was through a secret school that taught university type courses at different locations around the city. Marie’s older sister Bronya also loved learning. Together the two girls dreamed of going to America to study at university there.

However Marie and Bronya were not rich. So they could not pursue this dream of studying in America together. To pursue means to seek to accomplish a goal over a long period of time. Despite this problem, Marie and Bronya did not give up in their hope of going to university. The two girls made a deal with each other. They would attend university in Europe. However, they would not go together. They decided that Marie would work and pay for Bronya to live and attend university in Europe. Afterwards, Bronya would work and pay for Marie to attend. 

For five years, from the age of 19-24, Marie worked as a tutor and nanny for children. She sent most of the money she made to her sister. And in her spare time, Marie would study and read about science and math. 

When she was 24, Marie moved to Paris and started attending university at the Sorbonne, a famous university in France. Marie received money every month from Bronya, however, it was not enough to live and eat well. Marie mostly ate bread and butter. Because she was not eating a healthy diet, Marie got sick often. 

Despite these hardships, Marie finished a master’s degree in physics and a degree in math. 

Shortly after Marie graduated from the Sorbonne, she met a man named Pierre Curie. Pierre was a professor of physics. A professor is a teacher and researcher in a college or university. Marie and Pierre were introduced by a friend of Marie’s in order for Marie to try to find lab space for an experiment she was going to conduct. 

Marie and Pierre fell in love and they were married in 1895. They both loved science and physics. They worked together investigating radioactivity. Radioactivity is a process in which parts of matter break down and create energy.

In 1898, the Curies discovered two new chemical elements, polonium and radium. This was an amazing discovery…

They were awarded the Nobel Prize for Physics in 1903.

In 1906, Pierre had an unfortunate accident. He was knocked down by a carriage while crossing the road and he died. 

Marie took over his work after his death, including his teaching post at the Sorbonne. In doing so, she became the first woman to teach at the Sorbonne. She devoted herself to continuing the work that she and Pierre had started together.

In 1911, she received a second Nobel Prize, this time in Chemistry. 

The work that the Curies did was important in the development of x-ray technology. X-rays are electromagnetic wave of high energy and very short wavelength. They are able to pass through many materials that light cannot. X-rays are used for surgeries and other medical procedures, as they are able to help create images of what is inside of our bodies. Doctors can then use these X-ray images to figure out what is wrong with someone and where to operate, if necessary. 

During World War I, Marie helped ambulances have x-ray machines. She also volunteered with the ambulances and drove to the front lines to help wounded soldiers. 

Marie became the head of the International Red Cross’s radiological service. The International Red Cross is an organization dedicated to protecting victims of international wars.

In the 1920s, when Marie was in her 50s, she developed leukaemia, which is a type of cancer.  This was due to her exposure to radiation from her research. She died on July 4, 1934.

Marie Curie’s determination and hard work during her lifetime brought about amazing scientific developments that impact us all still today. As a woman physicist, she was a trailblazer in her field and faced backlash for her participation. But Marie was strong and determined. And she persisted in doing the work that she loved anyways. As a result, our medical and scientific world was changed. 

Is there something that you are passionate about? With hard work and determination, like Marie Curie, you can also make a difference in the world and in the things you are interested in. The key is to carry on despite times that are hard or backlash from others that you face to your efforts. If you believe in something and want to make a difference, you can do it!

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Close your eyes and imagine that you’re living in a futuristic city. Looking at the horizon, you can see towering wind turbines gently rotating in the wind. On the other side, you can see a whole field of solar panels. A nearby dam uses river water to produce even more electricity. The air you breathe is clean and fresh. The cars and other vehicles don’t give off any smoke or pollution. Your surroundings are clean and green, with plants growing all around you. Far away, you can see an old power plant, which is being demolished to make way for new, alternative energy sources. You can also see several large factories nearby, but none of them are emitting black smoke! This is what a city looks like where alternative energy rules the world .

So, what actually is alternative energy? As you may know, today we rely almost completely on petroleum and coal-based energy sources which are called fossil fuels. Energy companies obtain these resources from deep inside the earth’s surface and refine it to produce different fuels, like gas, gasoline, diesel and kerosene. These fuels are burned in power plants to produce electricity. Petroleum was formed by the remains of tiny plants and animals that died millions of years ago. Coal, on the other hand, was formed by larger plants like ferns. These dead materials were covered by layers of mud, rock, and soil over the years. Because of the pressure caused by all the top layers and the heat from earth’s core, the plant and animal remains transformed into petroleum and coal.  Because it took millions of years for petroleum and coal to form, this means that the amount of fossil fuel resources in the world are limited and won’t last forever. Since the number of people in the world  and businesses  in the world keep increasing and advancing, the need  for energy is also rising.  This is why finding new ways to harness energy is so important! Luckily, the world already has a lot of alternative energy sources and smart scientists and engineers are always working on finding new ways to harness energy and improve the technology we already have.

The alternative sources of energy include solar power, wind power, hydro power, tidal energy, geothermal energy, and biomass energy. These are called renewable energy, because they are naturally replenished in a short amount of time unlike petroleum. For example, there’s always more sun and wind! 

First let’s talk about solar energy. Solar energy is the energy we get from the sun. The sun is an incredibly huge, ball of energy which lights Earth with its rays we receive as sunlight. For thousands of years, people have used the sun’s energy to cook food, dry clothes, and keep warm. In our day, people have invented technologies to transform sunlight or solar energy into electrical power. This is done by solar cells, which are also called “photovoltaic” cells. “Photo” means “light” in Latin and “voltaic” stands for “electricity”. So, it’s basically turning sunlight into electricity! Pretty amazing, right? Solar panels are made by putting together many solar cells. If you’ve ever seen shiny panels on rooftops, those are solar panels. A few of my neighbors have them. In Arizona, solar panels are popular because we get LOTS of sunshine. It can also save people money, because the panels capture the light energy from the sun and turn it into electricity that can be used to power all the electric equipment in their house. Solar panels are sometimes used to power boats, food trucks, buildings, and satellites. Although solar energy IS renewable, how much energy they can produce depends on the time of day, season of the year and location in the world. For example, Arizona is much better for solar panels than a place like England that is often cloudy.

Now, let’s talk about wind energy. Wind energy is made from the wind, which is freely available to us just like sunlight. During the middle ages, people used wind power to pump water or grind grains. They built windmills to do that. Nowadays, people use a large structure called a wind turbine to make electricity using wind power. You may have seen these wind turbines as very tall structures that have long blades to capture the wind. Wind turbines can be around 400 feet tall, because the turbine blades need to reach high up into the atmosphere where the wind is faster than on the ground. The power of the wind is transformed into electricity by a small machine called a turbine generator which is connected to the turbine blades. Energy companies build hundreds of wind turbines in large fields where there are a lot of wind. These areas covered with wind turbines are called “wind farms”. When our family drives to California we pass through a huge wind farm. If you’ve never seen a wind farm look up pictures of San Gorgonio Pass. It’s pretty amazing.

The next form of alternative energy is hydropower or hydro energy and is made by using the power of moving water. In the past, people have used the power of water by making water wheels in rivers. Ancient Egyptians used hydro energy to grind grains and early Americans used it to saw wood. In the 1800’s, scientists discovered how to make electrical energy using hydro energy by turning the turbines of a generator. So, it works a little bit like wind power. To harness hydro energy today, people build a dam across a river which creates a water reservoir, which is like a man-made lake. By making a reservoir, we can have a controlled flow of water which can be used to generate electricity. That is, powerplant workers can control the amount and speed of the water flowing out of the dam. So, unlike solar or wind energy, hydro power is more constant and controllable. In Arizona we have the Hoover Dam and Glen Canyon Dam that generate a ton of electricity using hydro power. Be sure to lookup pictures of these impressive dams.

Tidal power is another type of hydro power. But instead of using inland waters like rivers and reservoirs, the energy of seawater is used to make electricity from tidal energy. Ocean tides usually occur twice daily, and tidal powerplants use turbine generators to convert that energy into electricity. Tidal turbines are placed in the path of the tidal waves. When the waves hit the turbine blades, they begin to spin. This movement is transformed into electric power using the turbine generators. So, you can see that the design of wind turbines and hydro turbines are very similar. However, tidal power can change based on the season. We cannot control it like how we control the power generated from a reservoir.

Geothermal energy is a form of alternative energy, that is obtained from the earth’s core. You may already know that the core of the earth is packed with heat. You can sometimes see this heat coming out of volcanoes and geysers. Geothermal energy can be used for heating, cooking and in electricity generation. We get it by circulating water or other liquids through underground tubes. The liquids absorb the geothermal heat and bring it back up. The captured heat can be directly used for heating. It can also be used to produce electricity using steam turbines.

Another really interesting form of alternative energy is biomass. Biomass is  biological materials such as sugar cane, straw, wood chips and many other plant materials. These can be burned to generate electricity instead of burning fossil fuels. Biomass can also be used to make other types of fuel such as diesel and biogas that can replace petroleum-based fuels. This makes biomass different and more important than the other types of alternative energy we discussed. That’s because biomass can be used to produce solid, liquid and gaseous forms of energy instead of just electricity. 

It’s pretty exciting to consider all of the new forms of energy that have been developed over the last 100 years and the improvements that are happening every day. Does alternative energy interest you? If so, do an internet search to watch videos of some of the amazing things people are doing to use renewable energy and what is being done at places like wind and solar farms. Also, more and more engineers and inventors are needed to solve the energy problems we have. Does engineering interest you? If so, math and science are important subjects to improve at. Also, being creative and coming up with lots of ideas. Can you think of an interesting way to use alternative energy to power something you use everyday?

With all of the new inventions, we have more and more options and not one of them is perfect, so many people believe a combination of technologies will solve the problems of pollution while sustaining all of our energy needs. There are over 7 billion people on this planet, so we need to find ways we can all live here and have enough energy without polluting this precious gift we can be given. 

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