SINTESIS DE PERIODO forth Grade

English, science, Math and Social studies

English

What Is An Adjective?

An adjective modifies a noun or a pronoun by describing, identifying, or quantifying words. An adjective usually precedes the noun or the pronoun which it modifies.

In the following examples, the highlighted words are adjectives:

The truck-shaped balloon floated over the treetops.

Mrs. Morrison papered her kitchen walls with hideous wall paper.

The small boat foundered on the wine dark sea.

The coal mines are dark and dank.

Many stores have already begun to play irritating Christmasmusic.

A battered music box sat on the mahogany sideboard.

The back room was filled with large, yellow rain boots.

CLASSWORK

Simple Present (Present Simple) - Introduction

Simple present is also called present simple.

The simple present expresses an action in the present taking place once, never or several times. It is also used for actions that take place one after another and for actions that are set by a timetable or schedule. The simple present also expresses facts in the present.

WOMAN AND MEN APPAREL PERSONAL DESCRIPTIONSAppearance

I am / You are / He is / She is … tall small overweight, fat slim young old … years old. beautiful / pretty (Mädchen / Frau), handsome (Junge / Mann) sun-tanned paleI have / You have / He has / She has (got) … blue / green / grey / brown eyes

 freckles a beard a full beard a moustache a goatee a stubbly beard blond hair red hair brown hair black hair dyed hair blond highlights short hair long hair straight hair curly hair / curls a bald head a square / round / triangular / oval face

 a big / small / long nose big / small ears

Make your description

Describe your favorite person (your mom, your dad, your brother or sister, etc)

MATH

How to Learn

Your life will be a lot easier when you can simply remember the multiplication tables.

So ... train your memory!

First, use the table above to start putting the answers into your memory.

Then use the Math Trainer - Multiplication to train your memory, it is specially designed to help you memorize the tables.

Use it a few times a day for about 5 minutes each, and you will learn your tables.

Try it now, and then come back and read some more ...

But here are some "tips" to help you even more:

Tip 1: Order Does Not Matter

When we multiply two numbers, it does not matter which isfirst or second, the answer is always the same.

Example: 3×5=15, and 5×3=15Another Example: 2×9=18, and 9×2=18

In fact, it is like half of the table is a mirror image of the other!

So, don't memorize both "3×5" and "5×3", just memorize that "a 3 and a 5 make 15" when multiplied.

This is very important! It nearly cuts the whole job in half.

In your mind you should think of 3 and 5 "together" making 15.

so you should be thinking something like this:

Tip 2: Learn the Tables in "Chunks"

It is too hard to put the whole table into your memory at once. So, learn it in "chunks" ...

A Start by learning the 5 times table.

B Then learn up to 9 times 5.C Is the same as B, except the

questions are the other way around. Learn it too.

D Lastly learn the "6×6 to 9×9" chunk

Then bring it all together by practicing the whole "10 Times Table"

And you will know your 10 Times Table!

(We look at the 12x table below)

Some Patterns

There are some patterns which can help you remember:

2× is just doubling the number. The same as adding the number to itself.

2×2=4, 2×3=6, 2×4=8, etc.

So the pattern is 2, 4, 6, 8, 10, 12, 14, 16, 18, 20

(And once you remember those, you also know 3×2, 4×2, 5×2, etc., right?)

5× has a pattern: 5, 10, 15, 20, etc. It ends in either 0 or 5.

9× has a pattern, too: 9, 18, 27, 36, 45, 54, 63, 72, 81, 90

Now, notice how the "units" place goes down: 9,8,7,6, ...? And at the same time, the "tens" place goes up: 1,2,3,...? Well, your hands can help!

Example: to multiply 9 by 8: hold your 8th finger down, and you can count "7" and "2" ... the answer is 72

10× is maybe the easiest of them all ... just put a zero after it

10×2=20, 10×3=30, 10×4=40, etc.

The Hardest Ones

For me the hardest ones are 6×7=42, 6×8=48 and 7×8=56. I often have to say in my mind:

"six sevens are forty-two", "six eights are forty-eight", "seven eights are fifty-six"

What About the 12 Times Table?

Sounds tough, but once you have mastered the 10× table, it is just a few steps away.

Firstly, 11× is mostly easy: from 11×2 to 11×9 you just put the two digits together. 11×2=22, 11×3=33, ..., 11×9=99.

And of course 2×, 5× and 10× just follow their simple rules you know already, so it just leaves these to remember:

3×12=36, 4×12=48, 6×12=72, 7×12=84, 8×12=96, 9×12=108

And the "Big 3":

11×11=121, 11×12=132 and 12×12=144

More Help

I also have a longer list of multiplication tips and tricks if you are interested.

You can test yourself using the times tables test.

You can try out Speed Math.

Learn Long Multiplication.

And if you are really good, see if you can beat the high scores at Reaction Math.

Division BasicsWhat is division? 

Division is breaking a number up into an equal number of parts. 

Example: 

20 divided by 4 = ? 

If you take 20 things and put them into four equal sized groups, there will be 5 things in each group. The answer is 5. 

 

20 divided by 4 = 5. 

Signs for Division 

There are a number of signs that people may use to indicate division. The most common one is ÷, but the backslash / is also used. Sometimes people will write one number on top of another with a line between them. This is also called a fraction. 

Example signs for "a divided by b": 

a ÷ ba/bab 

Dividend, Divisor, and Quotient 

Each part of a division equation has a name. The three main names are the dividend, the divisor, and the quotient.

Dividend - The dividend is the number you are dividing up

Divisor - The divisor is the number you are dividing by Quotient - The quotient is the answer

Dividend ÷ Divisor = Quotient 

Example: 

In the problem 20 ÷ 4 = 5 

Dividend = 20Divisor = 4Quotient = 5 

Special Cases 

There are three special cases to consider when dividing. 

1) Dividing by 1: When dividing something by 1, the answer is the original number. In other words, if the divisor is 1 then the quotient equals the dividend. 

Examples: 

20 ÷ 1 = 2014.7 ÷ 1 = 14.7 

2) Dividing by 0: You cannot divide a number by 0. The answer to this question is undefined. 

3) Dividend equals Divisor: If the dividend and the divisor are the same number (and not 0), then the answer is always 1. 

Examples: 

20 ÷ 20 = 114.7 ÷ 14.7 = 1 

Remainder 

If the answer to a division problem is not a whole number, the "leftovers" are called the remainder. 

For example, if you were to try and divide 20 by 3 you would discover that 3 does not divide evenly into 20. The closest numbers to 20 that 3 can divide into are 18 and 21. You pick the closest number that 3 divides into that is smaller than 20. That is 18. 

18 divided by 3 = 6, but there are still some leftovers. 20 -18 = 2. There are 2 remaining. 

We write the remainder after an "r" in the answer. 

20 ÷ 3 = 6 r 2 

Examples: 

12 ÷ 5 = 2 r 223 ÷ 4 = 5 r 318 ÷ 7 = 2 r 4 

Division is the Opposite of Multiplication 

Another way to think of division is as the opposite of multiplication. Taking the first example on this page: 

20 ÷ 4 = 5 

You can do the reverse, replacing the = with a x sign and the ÷ with an equal sign: 

5 x 4 = 20 

Examples: 

12 ÷ 4 = 33 x 4 = 12 

21 ÷ 3 = 77 x 3 = 21 

SCIENCEMatter is the Stuff Around You

Matter is everything around you. Matter is anything made of atoms and molecules. Matter is anything that has mass and takes up space. If you are new to the idea of mass, it is the amount of stuff in an object. We talk about the difference between mass and weight in another section. Matter is sometimes related to light and electromagnetic radiation. 

Even though matter can be found all over the Universe, you only find it in a few forms. As of 1995, scientists have identified five physical states of matter. Each of those states is sometimes called a phase. They may even discover one more state by the time you get old. 

Five States of MatterYou should know about solids, liquids, gases, plasmas, and one state called the Bose-Einstein condensate (BEC). Scientists have always known about solids, liquids, and gases. Plasma was a new idea when it was noticed by William Crookes in 1879. 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 the molecules and atoms. Think about solids. They are often hard and brittle. Liquids are all fluidy at room temperature. Gases are there, but you usually smell them before you can see them. You don't see them because their molecules are really far apart. The BEC is all about molecules that are really close to each other (even closer than atoms in a solid). 

Changing States of Matter

Elements and compounds can move from one physical state to another and not change their basic atomic parts. Oxygen (O2) as a gas still has the same properties as liquid oxygen. The liquid state is colder and denser, but the molecules (the basic parts) are still the same. Water (H2O) is another example. A water molecule 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're asking, "What is a chemical change?" Let's start with a glass of pure water. If the formula of water were to change, that would be a chemical change. If you could just add a second oxygen atom, you would have hydrogen peroxide (H2O2). The molecules in your glass would not be water anymore. The reality of creating hydrogen peroxide is more difficult. 

A chemical change happens when the atoms in a molecule are moved around or when atoms are added or taken away. Chemical changes happen when bonds between atoms are created or destroyed. Changing physical states of matter is about changing densities, pressures, temperatures, and other physical properties. The basic chemical structure does not change when there is a physical change. 

Related ActivitiesGeneralChemistryQuiz - Take the Quiz

GeneralMatterQuiz - Take the Quiz

Keywords to ReviewStates: States of matter are the different forms in which matter exists. The easy states to remember are solid, liquid, gas, and plasma. Although you might not find it around you every day, there is more plasma in the Universe than any state of visible matter. Remember that plasma is found in stars and between planets, stars, and systems of every galaxy. As you learn more, you will discover several other states of matter. Some of these states are still theoretical. 

Atoms: The basic unit of matter. Atoms are not the smallest pieces of matter you will find. They are made of protons, neutrons, and electrons. There are other smaller particles of matter as well. However, your studies will focus on atoms and the different types of atoms that make up each element of the periodic table. There are also variations of atoms called ions and isotopes. As the number of atoms increases, you have more matter. As you have more matter, you have more mass. 

Mass: Mass is the amount of matter in a thing. Usually, when a thing is heavier, it has a greater mass. If you have a piece of iron the size of a marble and a piece of iron the size of a bowling ball, the bowling ball will have more mass. That example looked at similar substances. If you have a balloon the size of a bowling ball, it may be the same size, but will definitely have a smaller mass. There is less matter in the balloon. When you use a scale, you measure weight. Weight is dependent on gravity while mass is not. Mass is measured in kilograms. 

Volume: The amount of space than an object can occupy. A balloon will have a volume similar to a bowling ball, but it will have a much different mass. You will usually encounter the idea of volume when you learn about gases and liquids. Gases and liquids can change their shape easily, but still take up the same volume. The concept of volume is also related to pressure. As pressure goes up or down, the volume of a gas changes as the distance between the molecules changes. Volume is measured in cubic meters or liters. 

Dark Matter: A theoretical form of matter that we cannot see. It does not emit electromagnetic radiation, so we are not able to see or detect it. Astronomers believe it may make up 84.5% of all matter in the Universe. When they studied the visible matter of the Universe, they found that something was exerting a gravitational effect on the visible matter. However, the source could not be found. That hidden source of gravity has been described as dark matter. 

ENERGY

Energy is Ability to do work. 

The energy can take a wide variety of forms - heat (thermal), light (radiant), mechanical, electrical, chemical, and nuclear energy. There are two types of energy - stored (potential) energy and working (kinetic) energy.  For example, the food you eat contains chemical energy, and your body stores this energy until you release it when you work or play.

All forms of energy are stored in different ways, in the energy sources that we use every day.  These sources are divided into two groups -- renewable (an energy source that we can use over and over again) and nonrenewable/conventional (an energy source that we are using up and cannot recreate in a short period of time).  Renewable energy sources include solar energy (which comes from the sun and can be turned into electricity and heat), wind energy,geothermal energy (from inside the earth), biomass from plants, and hydropower from water are also renewable energy sources.

However, we get most of our energy from nonrenewable energy sources, which include the fossil fuels -- oil, natural gas, and coal.  They're called fossil fuels because they were formed over millions and millions of years by the action of heat from the Earth's core and pressure from rock and soil on the remains (or "fossils") of dead plants and animals.  Another nonrenewable energy source is the element uranium, whose atoms we split (through a process called nuclear fission) to create heat and ultimately electricity.

We use all these energy sources to generate the electricity we need for our homes, businesses, schools, and factories. Electricity "energizes" our computers, lights, refrigerators, washing machines, and air conditioners, to name only a few uses.

We use energy to run our cars.  The gasoline we burn in our cars is made from oil.  We use energy to cook on an outdoor grill or soar in a beautiful hot-air balloon.  The propane for these recreational activities is made from oil and natural gas.

Energy is in everything.  We use energy to do everything we do, from making a jump shot to baking our favorite cookies to sending astronauts into space -- energy is there, making sure we have the power to do it all.

Read the brief biographies of individuals who have made significant contributions to energy and science.We get most of our energy from nonrenewable energy sources, which include the fossil fuels - oil, natural gas, and coal.  They're called fossil fuels because they were formed over millions and millions of years by the action of heat from the Earth's core and pressure from rock and soil on the remains (or "fossils") of dead plants and animals.  Another nonrenewable energy source is the element uranium, whose atoms we split (through a process called nuclear fission) to create heat and ultimately electricity.

Oil (Petroleum) 

Oil was formed from the remains of animals and plants that lived millions of years ago in a marine (water) environment before the dinosaurs.   Over the years, the remains were covered by layers of mud.  Heat and pressure from these layers helped the remains turn into what we today call crude oil.  The word "petroleum" means "rock oil" or "oil from the earth."

Where does Oil come from? Crude oil is a smelly, yellow-to-black liquid and is usually found in underground areas called reservoirs.  Scientists and engineers explore a chosen area by studying rock samples from the earth.  Measurements are taken, and, if the site seems promising, drilling begins.  Above the hole, a structure called a 'derrick' is built to house the tools and pipes going into the well.  When finished, the drilled well will bring a steady flow of oil to the surface.

Natural Gas 

Where does Natural Gas come from? Millions of years ago, the remains of plants and animals decayed and built up in thick layers.  This decayed matter from plants and animals is called organic material -- it was once alive.  Over time, the mud and soil changed to rock, covered the organic material and trapped it beneath the rock.  Pressure and heat changed some of this organic material into coal, some into oil (petroleum), and some into natural gas -- tiny bubbles of odorless gas.  The main ingredient in natural gas is methane, a gas (or compound) composed of one carbon atom and four hydrogen atoms.

How coal was formed?Coal is a combustible black or brownish-black sedimentary rock composed mostly of carbon and hydrocarbons. It is the most abundant fossil fuel produced in the United States.

Coal is a nonrenewable energy source because it takes millions of years to create. The energy in coal comes from the energy stored by plants that lived hundreds of millions of years ago, when the earth was partly covered with swampy forests. For millions of years, a layer of dead plants at the bottom of the swamps was covered by layers of water and dirt, trapping the energy of the dead plants. The heat and pressure from the top layers helped the plant remains turn into what we today call coal.

Uranium (nuclear) 

Nuclear energy is energy in the nucleus (core) of an atom. Atoms are tiny particles that make up every object in the universe. There is enormous energy in the bonds that hold atoms together. Nuclear energy can be used to make electricity. But first the energy must be released. It can be released from atoms in two ways: nuclear fusion and nuclear fission.

In nuclear fusion, energy is released when atoms are combined or fused together to form a larger atom. This is how the sun produces energy. 

In nuclear fission, atoms are split apart to form smaller atoms, releasing energy. Nuclear power plants use nuclear fission to produce electricity.

Electricity 

Electricity is the flow of electrical power or charge. It is a secondary energy source which means that we get it from the conversion of other sources of energy, like coal, natural gas, oil, nuclear power and other natural sources, which are called primary sources. The energy sources we use to make electricity can be renewable or non-renewable, but electricity itself is neither renewable or non-renewable.

Electrical phenomena have been studied since antiquity, though advances in the science were not made until the seventeenth and eighteenth centuries. Practical applications for electricity however

remained few, and it would not be until the late nineteenth century that engineers were able to put it to industrial and residential use. The rapid expansion in electrical technology at this time transformed

industry and society.

Electricity's extraordinary versatility as a source of energy means it can be put to an almost limitless set of applications which include transport, heating, lighting, communications, and computation. The backbone of modern industrial society is, and for the foreseeable future can be expected to remain,

the use of electrical power.

In general usage, the word "electricity" is adequate to refer to a number of physical effects. In scientific usage, however, the term is vague, and these related, but distinct, concepts are better identified by more precise terms:

Electric charge – a property of some subatomic particles, which determines their electromagnetic interactions. Electrically charged matter is influenced by, and produces, electromagnetic fields.

Electric current – a movement or flow of electrically charged particles, typically measured in amperes.

Electric field – an influence produced by an electric charge on other charges in its vicinity. Electric potential – the capacity of an electric field to do work on a electric charge, typically

measured in volts. Electromagnetism – a fundamental interaction between the magnetic field and the presence

and motion of an electric charge.

Hydrogen 

Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. At standard temperature and pressure, hydrogen is a colorless, odorless, nonmetallic, tasteless, highly flammable diatomic gas with the molecular formula H2. With an atomic weight of 1.00794 u, hydrogen is the lightest element.Hydrogen is the simplest element known to man. Each atom of hydrogen has only one proton. It is also the most plentiful gas in the universe. Stars are made primarily of hydrogen.

SOCIAL STUDIES

The United States of AmericaWelcome to the United States of America, the "land

of the free and home of the brave".

The USA's PeopleThe people of the United States are very diverse.  The people come from many different cultures and backgrounds and practice many different religions.  The American people are dedicated to the pursuit of happiness and freedoms of speech and religion.

Children go to public school from age 5 to 18.  The average school day is seven hours long with a 45 minute lunch and recess break.  Most high school graduates go on to study at a college or university.

The USA's HomesThere are many different types of houses in the United States.  People live in single family homes, apartments, townhouses (or rowhouses), mobile homes, and even igloos in Alaska.

The USA's CultureThe United States, which is also referred to as America, is made up of many diverse cultures, religions, and races.  In recent years it has become especially important to celebrate these differences in the cultures and to acknowledge that it is these distinct differences that make America unique and special.

Music is everywhere in the United States.   One special kind of music that is typically American is called Jazz.    Jazz music has been strongly influenced by the music of Africa.

Electronic media is an important part of culture in the United States.  Television, movies, music, and video games take up a great amount of American's free time.

Native Americans had lived in America for many centuries before it was discovered. Gradually, settlers from mostly Europe and Mexico populated the lands and drove off the Native Americans from the lands where they had lived for many thousands of years.  Even though Native Americans were the first people to live on the land of The United States, the Native American population is only 1% of the total population of the country.   Many state and city names come

from Native American words.   For example, Mississippi comes from the word misi which means big and sipi which means river.

The USA's Foods Some favorite foods that Americans like to eat include hamburgers, French fries, and a soda such as Coca-Cola or Pepsi.  In some areas of the United States people refer to Coke or Pepsi as a soft drink or soda pop.   Pizza is another favorite among Americans.  Ethnic foods such as Mexican and Chinese are also very popular.  The diverse population of people living in the United States has brought many different foods to this country.

The USA's ActivitiesBaseball is often referred to as the American National pastime.   Many Americans also play or enjoy watching football, soccer, hockey and basketball.   Girls as well as boys are involved in many sports in the United States.

The USA's AnimalsThe northwestern states are home to grizzly bears, elk, and deer.   Southern states are home to crocodiles and snakes.  Northeastern states have many opossum, raccoon, rabbits, skunk and deer in the forests.  There are many different climates and ecosystems in the United States that each hold a unique variety of animals and plants.

The USA's Holidays and Celebrations  Thanksgiving is celebrated on November 29th.   It is a time to give thanks for the harvest.  The holiday was started in the 1600's with the Pilgrims who first came to America.  President Lincoln declared Thanksgiving a national holiday in 1863.

On Thanksgiving it is tradition to celebrate with a big meal.  Most Americans serve turkey or ham, cranberry sauce, potatoes, corn, and pumpkin pie as well as many other foods.  Families usually try to have Thanksgiving together.

The USA's LandThe United States is made up of many cities, suburbs, and smaller towns.  Big cities can be found in every state.  The cities, states, and regions of the United States often have unique landmarks, foods, celebrations, and dialects that make them different from other areas of this vast nation.

It is usually cooler in the north and warmer in the south.  Most of the United States goes through four seasonal changes: winter, spring, summer, and fall.

The USA's Cities and LandmarksThe Statue of Liberty was a special gift that was given to the United States by the country of France.  The statue is located on a small island off the coast of New York and New Jersey.  The statue has been a symbol of freedom to Americans since it welcomed many immigrants on their way in to Ellis Island.

The USA's Facts:Area: 3,536,341 sq. milesCapital City: Washington, DC Population: 272 millionMain Language: EnglishCurrency: US DollarIndustries: leading industrial power in the world, highly diversified and technologically advanced; petroleum, steel, motor vehicles, aerospace, telecommunications, chemicals, electronics, food processing, consumer goods, lumber, mining