what is climate and climate change

8/6/2019 What is Climate and Climate Change

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What Is Climate and Climate Change?

Our weather is always changing and now scientists are discovering that our climate does not stay the

same either. Climate, the average weather over a period of many years, differs in regions of the world

that receive different amounts of sunlight and have different geographic factors, such as proximity to

oceans and altitude.

Climates will change if the factors that influence them fluctuate. To change climate on a global scale,

either the amount of heat that is let into the system changes, or the amount of heat that is let out of the

system changes. For instance, warming climates are either due to increased heat let into the Earth or a

decrease in the amount of heat that is let out of the atmosphere.

The heat that enters into the Earth system comes from the Sun. Sunlight travels through space and our

atmosphere, heating up the land surface and the oceans. The warmed Earth then releases heat back

into the atmosphere. However, the amount of sunlight let into the system is not always the same.

Changes in Earths orbit over thousands of years and changes in the Suns intensity affect the amount of

solar energy that reaches the Earth.

Heat exits the Earth system as the Earths surface, warmed by solar energy, radiates heat away.

However, certain gases in our atmosphere, called greenhouse gases, allow the lower atmosphere to

absorb the heat radiated from the Earths surface, trapping heat within the Earth system. Greenhouse

gases, such as water vapor, carbon dioxide, methane and nitrous oxide, are an important part of our

atmosphere because they keep Earth from becoming an icy sphere with surface temperatures of about0F. However, over the past century or so the amounts of greenhouse gases within our atmosphere

have been increasing rapidly, mainly due to the burning of fossil fuels, which releases carbon dioxide

into the atmosphere. Consequently, in the past one hundred years global temperatures have been

increasing more rapidly than the historic record shows. Scientists believe this accelerated heating of the

atmosphere is because increasing amounts of these greenhouse gases trap more and more heat.

Top Ten Things You Need to Know about Global Warming


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There are a number of widely held misconceptions about climate change, and unfortunately, these are

reflected in some of the educational materials available on the web. It is therefore crucial for teachers to

educate themselves and their students with accurate information and be careful not to reinforce

common but incorrect notions. The

following primer is a good place to

begin.

#1 Global warming is caused

primarily by carbon dioxide from

burning coal, oil and gas.

Certain gases that trap heat are

building up in Earth's atmosphere.

The primary culprit is carbon dioxide,

released from burning coal, oil and

natural gas in power plants, cars,

factories, etc. (and to a lesser extent

when forests are cleared). The

second is methane, released fromrice paddies, both ends of cows,

rotting garbage in landfills, mining

operations, and gas pipelines. Third

are chlorofluorocarbons (CFCs) and

similar chemicals, which are also

implicated in the separate problem

of ozone depletion (see #5 below).

Nitrous oxide (from fertilizers and

other chemicals) is fourth.

#2 Earth's average temperature hasrisen about 1 degree F in the past

100 years and is projected to rise

another 3 to 10 degrees F in the next

100 years.

While Earth's climate has changed

naturally throughout time, the

current rate of change due to human

activity is unprecedented during at

least the last 10,000 years. The

projected range of temperature rise

is wide because it includes a variety

of possible future conditions, such as

whether or not we control

greenhouse gas emissions and different ways the climate system might respond. Temperatures over the

US are expected to rise more than over the globe as a whole because land areas closer to the poles are

projected to warm faster than those nearer the equator.

#3 There is scientific consensus that global warming is real, is caused by human activities, and presents

serious challenges.


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Scientists working on this issue report that the observed global warming cannot be explained by natural

variations such as changes in the sun's output or volcanic eruptions. The most authoritative source of

information is the UN Intergovernmental Panel on Climate Change (IPCC) which draws upon the

collective wisdom of many hundreds of scientists from around the world. The IPCC projects global

temperature increases of 3 to 10 degrees F in the next 100 years and says that human activity is the

cause of most of the observed and projected warming.

#4 There's a difference between weather and climate.

Weather refers to the conditions at one particular time and place, and can change from hour to hour,

day to day, and season to season. Climate, on the other hand, refers to the long-term average pattern of

weather in a place. For example, we might say that the climate of South Florida is warm, moist and

sunny, although the weather on a particular day could be quite different than that. Long-term data are

needed to determine changes in climate, and such data indicate that Earth's climate has been warming

at a rapid rate since the start of intensive use of coal and oil in the late 1800s.

#5 The ozone hole does not cause global warming.

Ozone depletion is a different problem, caused mainly by CFCs (like Freon) once used in refrigerators

and air conditioners. In the past, CFCs were also used in aerosol spray cans, but that use was banned inthe US in 1978. CFCs deplete the stratospheric ozone layer that protects life on Earth from excess

ultraviolet light that can cause skin cancer and cataracts in humans and other damage to plants and

animals. An international agreement has phased out most uses of CFCs but the ozone layer is only just

beginning to recover, partly because these chemicals remain in the atmosphere for a long time.

(Although ozone depletion is not the cause of global warming, there are a number of connections

between the two. For example, many ozone-depleting compounds are also greenhouse gases. Some of

the compounds now replacing CFCs in order to protect ozone are also greenhouse gases. And ozone

itself is a greenhouse gas. In addition, while greenhouse gas build-up causes temperatures close to

Earth's surface to rise, it cause temperatures higher up, in the stratosphere, to fall. This stratospheric

cooling speeds ozone depletion, delaying the recovery of the ozone hole.)

#6 Global warming will have significant impacts on people and nature.

As temperatures continue to rise, precipitation is projected to come more frequently in the form of

heavy downpours. We can probably expect more extreme wet and dry conditions. In the western US,

where snowpack provides free storage of most of the water supply, reduced snowpack will make less

water available in summer. Coastal areas will become more vulnerable to storm surges as sea level rises.

Plant and animal species will migrate or disappear in response to changes in climate; New England may

lose its lobsters and maple trees as they move north into Canada. Natural ecosystems such as coral

reefs, mangrove swamps, arctic tundra, and alpine meadows are especially vulnerable and may

disappear entirely in some areas. While global warming will have impacts on natural and human systems

all around the world, the largest impacts will be on many natural ecosystems and on people who live in

developing countries and have few resources and little ability to adapt. On the positive side, warmer

winters will reduce cold-related stresses and growing seasons will lengthen. And there will be tradeoffs

in some areas, such as less skiing but more hiking; and fewer killing frosts but more bugs.

#7 Sea level has already risen due to warming and is projected to rise much more.

Many people are under the mistaken impression that only if the polar ice caps melt will sea level rise. In

fact, average sea level around the world has already risen 4 to 8 inches in the past 100 years due to

global warming and is expected to rise another 4 to 35 inches (with a best guess of around 19 inches) by

2100. The primary reason for this rise is that water expands as it warms. The second reason is that


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glaciers all over the world are melting, and when land-based ice melts, the water runs to the sea and

increases its level. Thousands of small islands are threatened by the projected sea-level rise for the 21st

century, as are low-lying coastal areas such as southern Florida. Of course, if there is any significant

melting of the polar ice sheets, the additional rise in sea level would be enormous (measured in feet not

inches). This is projected to occur on a time scale of millennia rather than centuries.

#8 Saving energy and developing alternative energy sources would help.

Each of us can reduce our contribution to global warming by using less greenhouse-gas-producing

energy: driving less, choosing fuel efficient cars and appliances (like refrigerators and water heaters),

and using solar energy where feasible for water and space heat. We can encourage our political and

business leaders to institute policies that will save energy and develop alternative energy sources that

do not release carbon dioxide. We can preserve existing forests and plant new ones. But even if we take

aggressive action now, we cannot completely prevent climate change because once carbon dioxide is in

the atmosphere, it remains there for about a century, and the climate system takes a long time to

respond to changes. But our actions now and in the coming decades will have enormous implications for

future generations.

#9 An international agreement known as the Kyoto Protocol has been negotiated to reduce greenhousegas emissions, but the US is not participating in it.

Because of its high energy consumption, the US has long emitted more carbon dioxide than any other

country. Because carbon dioxide remains in the atmosphere for about 120 years, it accumulates,

becomes equally distributed around the world, and has global effects. Thus, while using large amounts

of energy to achieve economic growth, the US and other wealthy nations have unintentionally burdened

the rest of the world with a long-term problem. And many negative impacts of climate change are likely

to be more severe for poorer countries that lack the resources to adapt. The US has more technological

and financial resources than other nations. The role of the US in reducing its own emissions and sharing

its technologies with other nations will thus be critical to the success of international efforts to limit

climate change. Meanwhile, we do not have to wait for the government to take action. Some

companies, governments and individuals have already committed to reducing their emissions ofgreenhouse gases without laws or treaties requiring them to do so.

#10 Protecting the world's climate by stabilizing atmospheric concentrations of greenhouse gases will

require enormous reductions in current emissions.

Even if ratified, the Kyoto Protocol in its present form is only a start and would not be nearly enough to

stabilize climate. It is estimated that greenhouse gas emissions would have to be reduced to less than

one third of current levels to stabilize atmospheric concentrations. This would require a major

transformation of the energy sector. A mix of new and existing energy technologies will be needed to

achieve this, including large increases in energy efficiency and renewable energy. Researchers are also

developing technology to capture and bury carbon dioxide thousands of feet underground. Major

increases in public and private research and development are needed to make the necessary

technologies available as rapidly and economically as possible.

What Happens When Climate Changes?

The Intergovernmental Panel on Climate Change (IPCC) is a group of scientists from around the world,

brought together by the United Nations to assess our understanding and the potential impacts of

climate change. Every five years they do a follow-up study to assess recent findings. Most important,


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they are identifying our options for lessening the rate of change and describing how societies can adapt

to it.

According to the IPCCs current findings, the worlds surface air temperature has increased an average of

0.6C (1.0 F) during the 20th Century. That may not sound like very much, but even one degree can

cause changes around the world. Additionally, given the accelerating rate of temperature rise, the IPCC

projects that during the 21st century, temperatures will rise much more than they did during the past

century. Since temperatures will likely continue to climb, it is important to understand how the Earth

has responded to climate change during the past century and to be able to better predict how it may

respond in the future.


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Sea-Level Rise

Sea level has risen 10-20 cm (4-8 inches) during the 20th century. The increased volume of water is a

result of both the melting of glaciers and the expansion of water with heat. Mountain glaciers have

become much smaller during the past century, especially those in low latitude locations like Mount

Kenya in Africa and the Andes in South America. Models predict that sea level may rise as much as 85cm (33 inches) during the 21st century. This would have dramatic effects on low-lying coastal

communities as shoreline erosion threatens houses and freshwater supplies are contaminated with salty

water. Certain natural ecosystems such as wetlands and coral reefs would also be in jeopardy as sea

level rises so rapidly.

Melting Arctic Sea Ice

Today, summer sea ice in the Arctic is about half as thick as it was in 1950. Just like an ice cube melting

in a glass of water, melting Arctic sea ice does not contribute to sea-level rise, except by the expansion

of seawater with heat. However, melting Arctic sea ice may eventually lead to global changes in water

circulation. The water from melted ice forms a layer at the sea surface that is less dense than the

underlying water because it is less salty, potentially preventing the pattern of deep ocean currents from

rising to the surface. Additionally, melting sea ice speeds up warming of the Arctic because water

absorbs 80% of sunlight, about the same amount that the cover of sea ice used to reflect.

Warmer oceans

Although a swim in a warm ocean sounds pleasant enough, dont be deceived! Warmed sea-surface

temperatures have been responsible for major destruction and will continue to wreak havoc as global

temperatures climb. About a quarter of the worlds coral reefs have died in the last few decades, many

of them affected by coral bleaching, a process tied directly to warming waters which weakens the coral

animals. Future warming may have consequences for other communities of marine life as well.Additionally, as tropical oceans continue to warm, stronger hurricanes might stir up trouble in the

future.

Floods

Warmer temperatures cause more evaporation of water, which, as part of thewater cycle, eventually

leads to more precipitation. In fact, the world has seen a 5-10% increase in precipitation over the past

century. However, the frequency of heavy rainfall events generally is likely to rise with global warming,

increasing the potential for flooding.

Droughts

While some parts of the world are treated to more precipitation as global warming persists, other parts

may experience increased levels of drought as temperatures rise. This is because places that are

typically dry, such as the centers of continents, will experience even more evaporation as global

temperatures climb. Scientists are still deciphering whether drought is currently increasing.


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Heat Waves

Heat waves are a great health risk. For example, a 1995 heat wave in Chicago caused 514 heat-related

deaths. As global temperatures warm, there is likely to be an increase in the number of heat waves and

their intensity, leading to an increase in the number of heat related deaths.

Warmer Winters

A possible upside to global warming, warmer winters mean that many deaths related to cold

temperatures might be avoided and that the growing season will last longer. There is already evidence

in Europe that the growing season has extended several days since the 1960s, with spring plants now

blooming about 6 days earlier and fall colors coming about 5 days later

Ecosystems change

Scientists believe that ecosystems will probably respond to climate change in one of two ways. Either

ecosystems will move, migrating to new locations that are more like their current climate, or they willchange, adapting to the changed climate, with some species becoming less abundant or locally extinct

and others thriving under the new conditions.

Agriculture

With drought affecting some areas and heat intensifying in the tropics, many areas are becoming

unsuitable for agriculture. In tropical areas that are already dry and hot, the amount of food harvested

will likely decrease with even small amounts of climate change. Less agriculture means less food.

Scientists predict that by the 2080s, about 80 million people, mostly within Africa, will be hungry

because of climate change.

Matter is the Stuff Around You

Matter is everything around you. Matter is anything made

of atoms and molecules. Matter is anything that has a mass.

Matter is also related to light and electromagnetic radiation.

Even though matter can be found all over the universe, you

usually find it in just a few forms. As of 1995, scientists have

identified five states of matter. They may discover one more

by the time you get old.

You should know about solids, liquids, gases, plasmas, and a

new one called Bose-Einstein condensates. The first four have

been around a long time. The scientists who worked with

the Bose-Einstein condensate received a Nobel Prize for their

work in 1995. But what makes a state of matter? It's about the physical state of molecules and atoms.


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Changing States of Matter

Elements and compounds can move from onephysical state to

another and not change. Oxygen (O2) as a gas still has the same

properties as liquid oxygen. The liquid state is colder and

denser but the molecules are still the same. Water is another

example. The compound water is made up of two hydrogen

(H) atoms and one oxygen (O) atom. It has the same molecular

structure whether it is a gas, liquid, or solid. Although its

physical state may change, its chemical state remains the

same.

So you ask, "What is a chemical state?" If the formula of water

were to change, that would be a chemical change. If you added

another oxygen atom, you would make hydrogen peroxide (H2O2). Its molecules would not be water

anymore. Changing states of matter is about changing densities, pressures, temperatures, and other

physical properties. The basic chemical structure does not change.

Atoms Around Us


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If you want to have a language, you will need an alphabet. If you want to build proteins, you will


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need amino acids. Other examples in chemistry are not any different. If you want to build molecules,


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you will need elements. Each element is a little bit different from the rest. Those elements are the


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alphabet to the language of molecules.


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Why are we talking about elements? This is the section on atoms.


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Let's stretch the idea a bit. If you read a book, you will read a

language. Letters make up that language. But what makes

those letters possible? Ummm... Ink? Yes! You need ink to

crate the letters. And for each letter, it is the same type of ink.

Confused? Don't be. Elements are like those letters. They have

something in common. That's where atoms come in. All

elements are made of atoms. While the atoms may have

different weights and organization, they are all built in the

same way. Electrons, protons, and neutrons make the universe

go.

If you want to do a little more thinking, start with particles of matter. Matter, the stuff around us, is

used to create atoms. Atoms are used to create the elements. Elements are used to create molecules. It

just goes on. Everything you see is built by using something else.

You could start really small...

- Particles of matter

- Atoms

- Elements

- Molecules

- Macromolecules

- Cell organelles

- Cells

- Tissues

- Organs

- Systems

- Organisms

- Populations

- Ecosystems

- Biospheres

- Planets

- Planetary Systems with Stars

- Galaxies

- The Universe

.And finish really big.

Wow. All of that is possible because of atoms.

ATOMS = BUILDING BLOCKS


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Atoms are the basis of chemistry. They are the basis for

everything in the Universe. You should start by remembering

that matter is composed of atoms. Atoms and the study of

atoms are a world unto themselves. We're going to cover basics

like atomic structure and bonding between atoms. As you learn

more, you can move to the biochemistry tutorials and see how

atoms form compounds that help the biological world survive.

SMALLER THAN ATOMS?

Are there pieces of matter that are smaller than atoms? Sure

there are. You'll soon be learning that atoms are composed of

pieces like neutrons, electrons, and protons. But guess what?

There are even smaller particles moving around in atoms. These super-small particles can be found

inside the protons and neutrons. Scientists have many names for those pieces, but you may have heard

of nucleons and quarks. Nuclear chemists and physicists work together with particle accelerators to

discover the presence of these tiny, tiny, tiny pieces of matter.

Even though those super tiny atomic particles exist, there are three basic parts of an atom. The parts are

the electrons, protons, and neutrons. What are electrons, protons, and neutrons? A picture works best.

You have a basic atom. There are three pieces to an atom. There are electrons, protons, and neutrons.

That's all you have to remember. Three things! As you know, there are over 100 elements in the periodic

table. The thing that makes each of those elements different is the number of electrons, protons, and

neutrons. The protons and neutrons are always in the center of the atom. Scientists call the center of

the atom the nucleus. The electrons are always found whizzing around the center in areas called

orbitals.

You can also see that each piece has either a "+", "-", or a "0."

That symbol refers to the charge of the particle. You know

when you get a shock from a socket, static electricity, or

lightning? Those are all different types of electric charges.

There are even charges in tiny particles of matter like atoms.

The electron always has a "-" or negative charge. The proton

always has a "+" or positive charge. If the charge of an entire

atom is "0", that means there are equal numbers of positive

and negative pieces, equal numbers of electrons and protons. The third particle is the neutron. It has a

neutral charge (a charge of zero).

Molecules, Mixtures & Compounds


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The universe is made up of atoms, the tiny building blocks of matter. This computer screen is made up

of atoms and so are your eyes and the rest of your body! In the last 110 years, scientists have discovered

that atoms themselves are made up of even smaller particles: an atom has a central nucleus made up of

protons and neutrons, and surrounded by electrons. These parts are so incredibly small that scientists

can only believe that they are there, based on the behaviors that atoms display. Electron microscopes

allow scientists to "see" highly magnified images of some atoms, but not the smaller particles that form

the atom.

Elements are the simplest substances in nature that cannot be broken down into smaller parts by

normal chemical means. They contain only atoms of the same type, ones that have identical chemical

properties. There are at least 90 naturally-occurring elements, plus man-made ones. If you look at

a periodic table, you'll see the names of each of these elements and some of their properties (such as

mass, or how heavy the atom is).

Molecules & Compounds

When atoms from different elements are joined together in groups, they formmolecules. The atoms in

molecules bind together chemically, which means that the atoms cannot be separated again by physicalmeans, such as filtration. The molecule has different properties from the elements from which is was

made. A water molecule is not three separate atoms, two hydrogen (H) and one oxygen (O), but it is

actually a unique H2O molecule with its own set of distinct properties.

Like elements that are formed of atoms of the same sort, compounds are formed of molecules of the

same sort. The elements can be combined into about 2 million different compounds! Did you know that

eggshells are made up of a calcium carbonate compound? And citric acid, which is found in oranges and

other citrus fruit, is a compound of carbon, hydrogen, and oxygen atoms. Your kids might find it helpful

to do a science research project finding other common compounds around your house. Make

hypotheses and do research using a chemistry reference book, web site, or text book to find out the

answers.

There are more carbon compounds than compounds of any other element. Organic compound is the

name for the carbon compounds found in all living things.

Mixtures - A Bit of This and That

All matter can be classified into two categories: pure substances and mixtures. Apure substance consists

of a single element or compound. Iron is formed only of iron (Fe) atoms; table salt is formed only of

sodium chloride (NaCl) molecules. A mixture, however, is made up of different compounds and/or

elements. When salt is added to water to make saltwater, it becomes a mixture. The salt and water

molecules do not combine to form new molecules, but only "mix" together while still retaining theiridentities. Air is also a mixture, containing just the right amounts of nitrogen, oxygen, and other gases

for life on Earth.

Not all mixtures have the same composition throughout. Salt water does, but Italian salad dressing does

not--the parts separate and are not perfectly blended orhomogenous. Mixtures of metals are

called alloys (bronze is an alloy of copper and tin); liquid mixtures (such as saltwater) are

called solutions.


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Some atoms have more protons, neutrons, and electrons, and some have fewer. Depending on how many

protons and electrons an atom has, the atom behaves differently. The simplest atoms have just one

proton and one electron - that's a hydrogen atom. A bunch of these atoms together make hydrogen gas.

More complicated atoms have more protons, more neutrons, and more electrons. A bunch of them

together make the other elements - helium, oxygen, copper,iron, gold, mercury, lead, and so on. The more

protons, neutrons, and electrons an atom has, the more mass it has, and the heavier it will be in

Earth's gravity. Hydrogen and helium are very light, and people use them to inflate balloons. Gold, which

has 79 protons, is very heavy, and lead, which has 82 protons, is even heavier, so people use lead to

make weights. The heaviest atom that occurs naturally is uranium.

Because protons have a positive electrical charge, the protons tend to push away from each other. This

would make atoms fall apart, except that another force, thestrong nuclear force, pulls them back

together. It's this balance of forces that makes atoms possible, and since everything is made out of

atoms, that's what makes everything possible.

But most things are not made out of just one kind of atom. Instead, different kinds of atoms get

together to form larger clumps of atoms called molecules.

A molecule is a group of two or moreatoms that stick together. Molecules (MOLL-uh-cyools) are so small

that nobody can see them, except with an electron microscope. Pretty much everything on Earth and

otherplanets is made of molecules, and so is some of the dust in space.

The first molecules formed about 300,000 years after the Big Bang, or just under 15 billion years ago.

They were the smallest kind of molecule - two hydrogen atoms joined together. As time went on,

and supernovas from exploding stars shot out different kinds of atoms, different kinds of molecules

formed and floated around in space. Because most of the atoms in space were hydrogen atoms, many of

these molecules combined hydrogen with another kind of atom. So hydrogen combined with oxygen to

make water molecules. Hydrogen combined with carbon to make hydrocarbons (what living things are built

out of). Even before there were any planets, water and hydrocarbons were floating around in space on

their own. Other molecules were made of heavier atoms, like silicon orgold. Still out in space, some

hydrocarbons got together and formed bigger molecules called amino acids.

When the planets did form, the ones that were further away from stars, likeJupiter and Neptune, were

made mostly of lighter molecules like water and hydrocarbons. Earth, which formed about 4.5 billion

years ago, was closer to the Sun, and made mostly of heavier molecules like iron. A lot of silicon and

other minerals also got to Earth, where they make up the rocks of the Earth's crust.


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We're not sure how or when the water, hydrocarbons, and amino acids got to Earth. But once they were

on Earth, the amino acids got together to make more and more complicated molecules - maybe

first ribonucleic acids, then proteins. The biggest organic molecule today is DNA. Each molecule of DNA has

more than two billion carbon atoms in it (plus a lot of other kinds of atoms too).

All molecules need some way to hold their atoms together. The two main ways that atoms hold together

are

y covalent bonding (a stronger kind, like in carbon dioxide and water)y ionic bonding (a weaker kind, like in most rocks)

Today people can make new kinds of molecules in laboratories and factories. Some of the biggest

molecules that people make are plastics, like what plastic garbage bags or plastic Legos are made of.

Plastics are also hydro-carbon molecules. People also make new molecules for medicines.

what is climate and climate change

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