Comparative adjectives

COMPARATIVE ADJECTIVES

Comparative adjectives are used to compare differences between the two objects they modify (larger, smaller, faster, higher). They are used in sentences where two nouns are compared, in this pattern:

Noun (subject) + verb + comparative adjective + than + noun (object).

The second item of comparison can be omitted if it is clear from the context (final example below).

EXAMPLES

• My house is larger than hers.
• This box is smaller than the one I lost.
• Your dog runs faster than Jim's dog.
• The rock flew higher than the roof.
• Jim and Jack are both my friends, but I like Jack better. ("than Jim" is understood)

SUPERLATIVE ADJECTIVES

Superlative adjectives are used to describe an object which is at the upper or lower limit of a quality (the tallest, the smallest, the fastest, the highest). They are used in sentences where a subject is compared to a group of objects.

Noun (subject) + verb + the + superlative adjective + noun (object).

The group that is being compared with can be omitted if it is clear from the context (final example below).

EXAMPLES

• My house is the largest one in our neighborhood.
• This is the smallest box I've ever seen.
• Your dog ran the fastest of any dog in the race.
• We all threw our rocks at the same time. My rock flew the highest. ("of all the rocks" is understood)

FORMING REGULAR COMPARATIVES AND SUPERLATIVES

Forming comparatives and superlatives is easy. The form depends on the number of syllables in the original adjective.

ONE SYLLABLE ADJECTIVES

Add -er for the comparative and -est for the superlative. If the adjective has a consonant + single vowel + consonant spelling, the final consonant must be doubled before adding the ending.

Adjective	Comparative	Superlative
tall	taller	tallest
fat	fatter	fattest
big	bigger	biggest
sad	sadder	saddest

TWO SYLLABLES

Adjectives with two syllables can form the comparative either by adding -er or by preceeding the adjective with more. These adjectives form the superlative either by adding -est or by preceeding the adjective with most. In many cases, both forms are used, although one usage will be more common than the other. If you are not sure whether a two-syllable adjective can take a comparative or superlative ending, play it safe and use moreand most instead. For adjectives ending in y, change the y to an i before adding the ending.

Adjective	Comparative	Superlative
happy	happier	happiest
simple	simpler	simplest
busy	busier	busiest
tilted	more tilted	most tilted
tangled	more tangled	most tangled

THREE OR MORE SYLLABLES

Adjectives with three or more syllables form the comparative by putting more in front of the adjective, and the superlative by putting most in front.

Adjective	Comparative	Superlative
important	more important	most important
expensive	more expensive	most expensive

IRREGULAR COMPARATIVES AND SUPERLATIVES

These very common adjectives have completely irregular comparative and superlative forms.

Adjective	Comparative	Superlative
good	better	best
bad	worse	worst
little	less	least
much	more	most
far	further / farther	furthest / farthest

What is Physics ? || Indian Science

What is Physics ?

Energy

                                       Energy

What is Energy? 

The simplest definition of energy is "the ability to do work". Energy is how things change and move. It's everywhere around us and takes all sorts of forms. It takes energy to cook food, to drive to school, and to jump in the air. 

Different forms of Energy 

Energy can take a number of different forms. Here are some examples:

• Chemical - Chemical energy comes from atoms and molecules and how they interact.
• Electrical - Electrical energy is generated by the movement of electrons.
• Gravitational - Large objects such as the Earth and the Sun create gravity and gravitational energy.
• Heat - Heat energy is also called thermal energy. It comes from molecules of different temperatures interacting.
• Light - Light is called radiant energy. The Earth gets a lot of its energy from the light of the Sun.
• Motion - Anything that is moving has energy. This is also called kinetic energy.
• Nuclear - Huge amounts of nuclear energy can be generated by splitting atoms.
• Potential - Potential energy is energy that is stored. One example of this is a spring that is pressed all the way down. Another example is a book sitting high on a shelf.

Units of Measure for Energy 

In physics, the standard unit of measure for energy is the joule which is abbreviated as J. There are other units of measure for energy that are used throughout the world including kilowatt-hours, calories, newton-meters, therms, and foot-pounds. 

Law of Conservation of Energy 

This law states that energy is never created or destroyed, it is only changed from one state to another. One example is the chemical energy in food that we turn into kinetic energy when we move. 


Renewable and Nonrenewable 

As humans we use a lot of energy to drive our cars, heat and cool our houses, watch TV, and more. This energy comes from a variety of places and in a number of forms. Conservationists classify the energy we use into two types: renewable and nonrenewable. Nonrenewable energy uses up resources that we cannot recreate. Some examples of this are gas to run our car and coal burned in power plants. Once they are used, they are gone forever. A renewable energy source is one that can be replenished. Examples of this include hydropower from turbines in a dam, wind power from windmills, and solar power from the sun. 

The more renewable power we use the better for our planet and for future generations as they won't run out of resources someday. 

Fun Facts about Energy

• In 2008 about 7% of the energy used in the United States was from renewable sources.
• A modern windmill or turbine can generate enough electricity to power around 300 homes.
• People have used waterpower to grind grain for over 2,000 years.
• Geothermal power uses energy from geysers, hot springs, and volcanoes.
• The entire world could be powered for a year from the energy from the sun that falls on the Earth's surface in one hour. We just need to figure out how to harness it!

Motion Glossary and Terms

                         Motion Glossary and Terms

 Acceleration - Acceleration is the measurement of the change in an object's velocity. It is equal to the change in velocity over the change in time. Acceleration is a vector. 

Collision - A collision in physics occurs when any two objects bump into each other. 

Displacement - In physics, displacement refers to an object's overall change in position. It is a vector quantity. 

Energy - Energy is the ability to do work. The standard unit of measure for energy is the joule. 

First law of motion - The first law of motion states that any object in motion will continue to move in the same direction and speed unless external forces act on it. 

Force - Force is the measurement of a push or pull on an object. Force is a vector measured in newtons. 

Friction - Friction is the resistance of motion when one object rubs against another. It is a force and is measured in newtons. 

Gravity - Gravity is a force caused when the mass of physical bodies attract each other. On Earth gravity pulls at objects with an acceleration of 9.8 m/s². 

Impulse - An impulse is a change in momentum. 

Joule - The joule is the standard unit of measure for energy and work. 

Kinetic energy - Kinetic energy is the energy an object has due to its motion. It is a scalar quantity calculated using the formula KE = ½ * m * v², where m = mass and v = velocity. 

Mass - Mass is a measurement of how much matter is in an object. It is usually measured in kilograms. 

Momentum - Momentum is a measurement of mass in motion. Momentum is equal to the mass times the velocity of an object. It is a vector measured in newton-seconds. 

Newton - The newton is the standard unit of measure for force. 

Pascal - The pascal is the standard unit of measure for pressure. 

Potential energy - Potential energy is the energy stored by an object due to its state or position. It is measured in joules. 

Power - Power is a measurement of the rate at which energy is used. Power is calculated by dividing work over time. The standard unit for power is the watt. 

Pressure - Pressure is the force over a given area. Pressure is measured in pascals. 

Scalar - A scalar is a measurement that only measures the magnitude. Unlike a vector, a scalar does not have direction. 

Second law of motion - The second law of motion states that the greater the mass of an object, the more force it will take to accelerate the object. 

Simple machine - A simple machine is a basic mechanical device for applying a force and doing work. Some examples of simple machines include the lever, pulley, inclined plane, wedge, and screw.

Speed - Speed is the measurement of how fast on object moves relative to a reference point. It is a scalar quantity measured by distance over time. 

Third law of motion - The third law of motion states that for every action there is an equal and opposite reaction. 

Vector - A vector is a quantity that has both a magnitude and a direction. 

Velocity - Velocity is the rate of change in an object's position. Velocity is a vector quantity. The magnitude of velocity is the object's speed. 

Watt - The watt is the standard unit of measure for power. 

Weight - Weight is the force of gravity on an object. In physics, weight is measured in newtons. 

Work - Work occurs in physics when a force acts on an object to move it some distance. Work is equal to the force times the distance and is measured in joules. 

What is Radiant Energy?

What is Radiant Energy?

What's the first thing you think of when you think of the sun; warmth, light, sunburns, blue skies, growing plants? The energy from the sun is an important factor for life on earth. The heat and light we associate with the sun are forms of radiant energy. Energy is the ability to do work, and radiation is energy that travels in waves. There are other forms of radiant energy besides heat and light. All the different forms of radiant energy make up the -electromagnetic spectrum.

What is the Electromagnetic Spectrum?

Have you observed a rainbow after it rains? All those colors of light are a small part of the electromagnetic spectrum and the only part we can see. We see the light from the sun, but don't necessarily see the heat. Heat is known as infrared light. Some of the other forms of radiant energy you may know are ultraviolet light, x-rays, gamma rays, microwaves and radio waves. All these forms of radiant energy travel in waves at the same speed but each forms' waves are different in size. Radio waves are very large, low energy waves traveling through the air (though we can't see them) in comparison to x-rays that are small, high energy waves.

A rainbow is radiant energy we can see

How is it used?

Sir William Crookes discovered the electromagnetic spectrum in 1885. That's over 130 years ago! Scientists are still studying and learning about radiant energy, how it works and how we can use it. Radiant energy is an important part of our world. Telecommunications like wireless networks, remote controls, heating, lighting, and branches of the medical field such as laser surgery and radiation therapy are just a few examples of our current technological uses of radiant energy.

What is Physics? |

What is Physics? |

Must and Have to

What's the difference between must and have to?

Must and have to are modal verbs in English. This page will guide you to the proper use of these modals.

Must

1. We use must to make a logical deduction based on evidence. It indicates that the speaker is certain about something:
Examples:

• It has rained all day, it must be very wet outside.
• The weather is fantastic in California. It must a lot fun to live there.

2. Must is also used to express a strong obligation.
Examples:

• Students must arrive in class on time.
• You must stop when the traffic lights are red.
• I must go to bed.

Have to

Like must, have to is used to express strong obligation, but when we use have to there is usually a sense of external obligation. Some external circumstance makes the obligation necessary.
Examples:

• I have to send an urgent email.
• I have to take this book back to the library.