Sunday, January 26, 2014
ENERGY
If you want to learn about Energy in terms of Renewable and
Non-renewable Energy, please select an option below:
What is energy?
Look around you. Is anything moving?
Can you hear, see or feel anything? Sure... this is because something is making something happen, and most probably, there is some power at work. This power or ability to make things happen is what we can call energy. It makes things happen. It makes change possible.
Look at the sketch below to see an example of things working, moving, or happening... with energy.
Energy move cars along the roads and make aeroplanes fly. It plays our music on the radio and lights our homes. Energy is needed for our bodies, together with plants to grow and move about.
Scientists define ENERGY as the ability to do work.
Energy can be neither created nor destroyed.
Energy can be (is) stored or transferred from place to place, or object to object in different ways. There are various kinds of energy.
Let's start by looking at KINETIC ENERGY
All moving things have kinetic energy. It is energy possessed by an object due to its' motion or movement. These include very large things, like planets, and very small ones, like atoms. The heavier a thing is, and the faster it moves, the more kinetic energy it has.
Now let's see this illustration below.
There is a small and large ball resting on a table.
Let us say both balls will fall into the bucket of water.
Let's see what is going to happen.
You will notice that the smaller ball makes a little splash as it falls into the bucket. The heavier ball makes a very big splash. Why?
Note the following:
1. Both balls had potential energy as they rested on the table.
2. By resting up on a high table, they also had gravitational energy.
3. By moving and falling off the table (movement), potential and gravitational energy changed to Kinetic Energy. Can you guess which of the balls had more kinetic energy? (The big and heavier ball)
Let's see another classic example.
If you are in a hot room and you turn on the fan, what do you begin to feel? Air (wind). The speedy movement of the fan's blades has kinetic energy, which is then transferred into air (wind) that you now feel.
Other examples of Kinetic Energy include a moving car, moving wheel, and a moving arrow.
Click to see a video example of kinetic energy in use.
SOUND ENERGY
Sound is the movement of energy through substances in longitudinal (compression/rarefaction) waves.
Sound is produced when a force causes an object or substance to vibrate — the energy is transferred through the substance in a wave. Typically, the energy in sound is far less than other forms of energy.
Let's see this illustration.
A vibrating drum in a disco transfers energy to the room as sound. Kinetic energy from the moving air molecules transfers the sound energy to the dancers eardrums. Notice that Kinetic (movement) energy in the sticks is being transferred into sound energy.
Sound vibrations create sound waves which move through mediums such as
air and water before reaching our ears.
Click the icon below to read more on how energy is
measured and how a sound wave is represented.
HEAT-THERMAL ENERGY
Thermal energy is what we call energy that comes from heat. For example, a cup of hot tea has thermal energy in the form of kinetic energy from its' particles. When you pour some milk into your tea, some of this energy is transferred to the particles in cold milk. What happens next? The cup of tea is cooler because it lost thermal energy to the milk.
We cannot discuss Thermal Energy without touching on Temperature.
Temperature
The temperature of an object is to do with how hot or cold it is, measured in degrees Celsius (°C). Temperature can also be measured in in a Fahrenheit scale, named after the German physicist called Daniel Gabriel Fahrenheit (1686 – 1736). It is denoted by the symbol 'F'. In Fahrenheit scale, water freezes at 32 °F, and boils at 212 °F.
ELECTRICAL ENERGY
A battery transfers stored chemical energy as charged particles called electrons, typically moving through a wire. For example, electrical energy is transferred to the surroundings by the lamp as light energy and thermal (heat) energy.
Lightning is one good example of electrical energy in nature, so powerful that it is not confined to a wire. Thunderclouds build up large amounts of electrical energy. This is called static electricity. They are released during lightning when the clouds strike against each other.
Click to see a video example of electrical energy in use.
What is energy?
Look around you. Is anything moving?
Can you hear, see or feel anything? Sure... this is because something is making something happen, and most probably, there is some power at work. This power or ability to make things happen is what we can call energy. It makes things happen. It makes change possible.
Look at the sketch below to see an example of things working, moving, or happening... with energy.
Energy move cars along the roads and make aeroplanes fly. It plays our music on the radio and lights our homes. Energy is needed for our bodies, together with plants to grow and move about.
Scientists define ENERGY as the ability to do work.
Energy can be neither created nor destroyed.
KINDS OF ENERGY
With the above explanation in mind, let us learn more.Energy can be (is) stored or transferred from place to place, or object to object in different ways. There are various kinds of energy.
Let's start by looking at KINETIC ENERGY
All moving things have kinetic energy. It is energy possessed by an object due to its' motion or movement. These include very large things, like planets, and very small ones, like atoms. The heavier a thing is, and the faster it moves, the more kinetic energy it has.
Now let's see this illustration below.
There is a small and large ball resting on a table.
Let us say both balls will fall into the bucket of water.
Let's see what is going to happen.
You will notice that the smaller ball makes a little splash as it falls into the bucket. The heavier ball makes a very big splash. Why?
Note the following:
1. Both balls had potential energy as they rested on the table.
2. By resting up on a high table, they also had gravitational energy.
3. By moving and falling off the table (movement), potential and gravitational energy changed to Kinetic Energy. Can you guess which of the balls had more kinetic energy? (The big and heavier ball)
Let's see another classic example.
If you are in a hot room and you turn on the fan, what do you begin to feel? Air (wind). The speedy movement of the fan's blades has kinetic energy, which is then transferred into air (wind) that you now feel.
Other examples of Kinetic Energy include a moving car, moving wheel, and a moving arrow.
Click to see a video example of kinetic energy in use.
SOUND ENERGY
Sound is the movement of energy through substances in longitudinal (compression/rarefaction) waves.
Sound is produced when a force causes an object or substance to vibrate — the energy is transferred through the substance in a wave. Typically, the energy in sound is far less than other forms of energy.
Let's see this illustration.
A vibrating drum in a disco transfers energy to the room as sound. Kinetic energy from the moving air molecules transfers the sound energy to the dancers eardrums. Notice that Kinetic (movement) energy in the sticks is being transferred into sound energy.
Sound vibrations create sound waves which move through mediums such as
air and water before reaching our ears.
Click the icon below to read more on how energy is
measured and how a sound wave is represented.
HEAT-THERMAL ENERGY
Thermal energy is what we call energy that comes from heat. For example, a cup of hot tea has thermal energy in the form of kinetic energy from its' particles. When you pour some milk into your tea, some of this energy is transferred to the particles in cold milk. What happens next? The cup of tea is cooler because it lost thermal energy to the milk.
We cannot discuss Thermal Energy without touching on Temperature.
Temperature
The temperature of an object is to do with how hot or cold it is, measured in degrees Celsius (°C). Temperature can also be measured in in a Fahrenheit scale, named after the German physicist called Daniel Gabriel Fahrenheit (1686 – 1736). It is denoted by the symbol 'F'. In Fahrenheit scale, water freezes at 32 °F, and boils at 212 °F.
A thermometer is used to measure the temperature of an object.
Let's look at two examples to see the difference between heat and temperature.
A
swimming pool at 30°C is at a lower temperature than a cup of tea at
80°C. But the swimming pool contains more water, so it stores more
thermal energy than the cup of tea.
To
boil water we must increase its' temperature to 100°C. It takes longer
to boil a large beaker of water than a small beaker because the large
beaker contains more water and needs more thermal energy to reach
100°C.
Let's look at two examples to see the difference between heat and temperature.
A
swimming pool at 30°C is at a lower temperature than a cup of tea at
80°C. But the swimming pool contains more water, so it stores more
thermal energy than the cup of tea.To
boil water we must increase its' temperature to 100°C. It takes longer
to boil a large beaker of water than a small beaker because the large
beaker contains more water and needs more thermal energy to reach
100°C.
CHEMICAL ENERGY
Chemical Energy is energy stored in the bonds of chemical compounds (atoms and molecules). It is released in a chemical reaction, often producing heat as a by product (exothermic reaction). Batteries, biomass, petroleum, natural gas, and coal are examples of stored chemical energy. Usually, once chemical energy is released from a substance, that substance is transformed into an entirely new substance.
For example, when an explosive goes off, chemical energy stored in it is transferred to the surroundings as thermal energy, sound energy and kinetic energy.
Let's see one good example in the fire-place illustration below.
The
dry wood is a store of chemical energy. As it burns in the fireplace,
chemical energy is released and converted to thermal energy (heat) and
light energy. Notice that the wood now turns into ashes (a new substance)
Food is also a good example of stored chemical energy. This energy is released during digestion. Molecules in our food are broken down into smaller pieces. As the bonds between these atoms loosen or break, a chemical reaction will occur, and new compounds are created. When the bonds break or loosen, oxidation occurs almost instantly.
In the example above, notice that new compounds are formed from the breakdown of other molecules or atoms. Chemical reaction causes that.
A chemical reaction is involved in this breakdown. The energy produced keeps us warm, maintain and repair bodies, and makes us able to move about. Different foods store different amounts of energy.
Energy in food is measured in kilocalories (or Calories). Can you think of some very good examples of chemical energy?
Click to see Video example of chemical energy.
Chemical Energy is energy stored in the bonds of chemical compounds (atoms and molecules). It is released in a chemical reaction, often producing heat as a by product (exothermic reaction). Batteries, biomass, petroleum, natural gas, and coal are examples of stored chemical energy. Usually, once chemical energy is released from a substance, that substance is transformed into an entirely new substance.
For example, when an explosive goes off, chemical energy stored in it is transferred to the surroundings as thermal energy, sound energy and kinetic energy.
Let's see one good example in the fire-place illustration below.
The
dry wood is a store of chemical energy. As it burns in the fireplace,
chemical energy is released and converted to thermal energy (heat) and
light energy. Notice that the wood now turns into ashes (a new substance)Food is also a good example of stored chemical energy. This energy is released during digestion. Molecules in our food are broken down into smaller pieces. As the bonds between these atoms loosen or break, a chemical reaction will occur, and new compounds are created. When the bonds break or loosen, oxidation occurs almost instantly.
In the example above, notice that new compounds are formed from the breakdown of other molecules or atoms. Chemical reaction causes that.
A chemical reaction is involved in this breakdown. The energy produced keeps us warm, maintain and repair bodies, and makes us able to move about. Different foods store different amounts of energy.
Energy in food is measured in kilocalories (or Calories). Can you think of some very good examples of chemical energy?
Click to see Video example of chemical energy.
ELECTRICAL ENERGY
A battery transfers stored chemical energy as charged particles called electrons, typically moving through a wire. For example, electrical energy is transferred to the surroundings by the lamp as light energy and thermal (heat) energy.
Lightning is one good example of electrical energy in nature, so powerful that it is not confined to a wire. Thunderclouds build up large amounts of electrical energy. This is called static electricity. They are released during lightning when the clouds strike against each other.
Click to see a video example of electrical energy in use.
Sunday, January 12, 2014
Friday, January 3, 2014
Fun Magnet Facts for Kids
Check out our fun magnet facts for kids and enjoy learning some truly magnetic information about the world of magnetism.
Find out what a magnet
is, how magnetic fields work, which metals are magnetic and which
aren't, how the Earth's core relates to magnetism and much more. Read
on and have fun learning about magnets!
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Magnets are objects that produce an area of magnetic force called a magnetic field.
-
Magnetic fields by themselves are invisible to the human eye.
-
Iron filings can be used to show magnetic fields created by magnets (such as in the picture to the right).
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Magnets only attract certain types of metals, other materials such as glass, plastic and wood aren't attracted.
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Metals such as iron, nickel and cobalt are attracted to magnets.
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Most metals however are not attracted to magnets, these include copper, silver, gold, magnesium, platinum, aluminium and more. They may however magnetize a small amount while placed in a magnetic field.
-
Magnetism can attract magnetic objects or push them away.
-
Magnets have a magnetic north pole and a magnetic south pole. If the same pole of two magnets are placed near each other they will push away (repel), while if different poles are placed near each other they will pull together (attract).
-
Magnetic objects must be inside the magnetic field to respond, which is why you may have to move a magnet closer for it to have an effect.
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The Earth's core is believed to be a mix (alloy) of iron and nickel, giving the Earth its own magnetic field.
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The Earth's magnetic field is responsible for deflecting the solar wind, charged particles that come from the Sun.
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Magnetic compasses use the Earth's magnetic field to help navigate in north, south, east and west directions.
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Electromagnets are created by an electric current running through a surrounding coil. They have many uses including the generation of electricity in hydroelectric dams.
Static Electricity Experiment
 They say opposites attract and
that couldn't be truer with these fun static electricity experiments.
Find out about positively and negatively charged particles using a few
basic items, can you control if they will be attracted or unattracted to
each other?
What you'll need:
Instructions:
What's happening?
Rubbing the balloons
against the woolen fabric or your hair creates static electricity. This
involves negatively charged particles (electrons) jumping to positively
charged objects. When you rub the balloons against your hair or the
fabric they become negatively charged, they have taken some of the
electrons from the hair/fabric and left them positively charged.
They say opposites
attract and that is certainly the case in these experiments, your
positively charged hair is attracted to the negatively charged balloon
and starts to rise up to meet it. This is similar to the aluminium can
which is drawn to the negatively charged balloon as the area near it
becomes positively charged, once again opposites attract.
In the first
experiment both the balloons were negatively charged after rubbing them
against the woolen fabric, because of this they were unattracted to each
other.
|
Introduction to Electricity
Electricity is the
movement of charged electric particles called electrons. Learn more
about it with this great electricity introduction video. See how
current, amperes, volts and circuits are related as well as why
electrical safety is so important.
We use electricity to
light the rooms in our homes, power our televisions, microwaves,
fridges, heaters, washing machines and so much more, enjoy this
electricity video clip and learn how it all works.
Fun electricity facts for kids
Electricity plays an important role in everyday life, learn more about static electricity, electric eels, circuits, lightning, electric shock, volts, amps and much more.
* Modern society relies heavily on the convenience and versatility of electricity. It powers your microwave, helps light your house, lets you watch TV and so much more.
* Electric current is measured in amperes (amps).
* Electric potential energy is measured in volts.
* Two positive charges repel each other, as do two negative charges. Opposite charges on the other hand attract each other.
* When an electric charge builds up on the surface of an object it creates static electricity. You have probably experienced static electricity in the form of a small electric shock, which is what happens when the electric charge is quickly neutralized by an opposite charge.
* Electric eels can produce strong electric shocks of around 500 volts for both self defense and hunting.
* Electric circuits can contain parts such as switches, transformers, resistors and transformers.
* A common way to produce electricity is by hydropower, a process that generates electricity by using water to spin turbines attached to generators.
* The world’s biggest source of energy for producing electricity comes from coal. The burning of coal in furnaces heats boiler water until it becomes steam which then spins turbines attached to generators. Lightning is a discharge of electricity in the atmosphere.
* Lightning bolts can travel at around 210,000 kph (130,000 mph), while reaching nearly 30,000 °C (54,000 °F) in temperature.
* Electricity plays a role in the way your heart beats. Muscle cells in the heart are contracted by electricity going through the heart. Electrocardiogram (ECG) machines used in hospitals measure the electricity going through someone’s heart, when the person is healthy it usually shows a line moving across a screen with regular spikes as the heart beats.
* You may have heard of direct current (DC) and alternating current (AC). The difference between the two is in the way the electrons flow. In DC electrons move in a single direction while in AC they change directions, switching between backwards and forwards. The electricity use in your home is AC while DC comes from sources that include batteries.
* Back in the 1880’s there was even a ‘war of currents’ between Thomas Edison (who helped invent DC) and Nikola Tesla (who helped invent AC). Both wanted their system to be used with AC eventually winning out due to the fact that it is safer and can be used over longer distances.
* Electric fields work in a similar way to gravity with an important exception being that while gravity always attracts, electric fields can either attract or repulse.
* American Benjamin Franklin carried out extensive electricity research in the 18th century, inventing the lightning rod amongst his many discoveries. Lightning rods protect buildings in the event of lightning by conducting lightning strikes through a grounded wire.
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