5 Magnet Magic Show

By Unknown

5

Magnet Magic Show

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This is a Magic Show using Magnet. Please Watch !!!

 

 Facts about Magnet

• 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).

• Magnets only attract certain types of metals, other materials such as glass, plastic and wood aren't attracted.

• Metals such as iron, nickel and cobalt are attracted to magnets.

• 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.

• The Earth's core is believed to be a mix (alloy) of iron and nickel, giving the Earth its own magnetic field.

• The Earth's magnetic field is responsible for deflecting the solar wind, charged particles that come from the Sun.

• Magnetic compasses use the Earth's magnetic field to help navigate in north, south, east and west directions.

•   Electromagnets are created by an electric current running through a surrounding coil. They have many uses including the generation of electricity in hydroelectric dams.

3 Food Chain

By Unknown

3

Food Chain

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Boys & Girls; Do you know what is a "Food Chain" ?

A food chain is a linear sequence of links in a food web starting from a trophic species that eats no other species in the web and ends at a trophic species that is eaten by no other species in the web. A food chain differs from a food web, because the complex polyphagous network of feeding relations are aggregated into trophic species and the chain only follows linear monophagous pathways. A common metric used to quantify food web trophic structure is food chain length. In its simplest form, the length of a chain is the number of links between a trophic consumer and the base of the web and the mean chain length of an entire web is the arithmetic average of the lengths of all chains in a food web.

 

The food chain length is a continuous variable that provides a measure of the passage of energy and an index of ecological structure that increases in value counting progressively through the linkages in a linear fashion from the lowest to the highest trophic (feeding) levels. Food chains are often used in ecological modeling (such as a three species food chain). They are simplified abstractions of real food webs, but complex in their dynamics and mathematical implications. Ecologists have formulated and tested hypotheses regarding the nature of ecological patterns associated with food chain length, such as increasing length increasing with ecosystem size, reduction of energy at each successive level, or the proposition that long food chain lengths are unstable. Food chain studies have had an important role in ecotoxicology studies tracing the pathways and biomagnification of environmental contaminants. Food chain vary in length from three to six or more levels. A food chain consisting of a flower, a frog, a snake and an owl consists of four levels; whereas a food chain consisting of grass, a grasshopper, a rat, a snake and finally a hawk consists of five levels. Producers, such as plants, are organisms that utilize solar energy or heat energy to synthesise starch. All food chains must start with a producer. Consumers are organisms that eat other organisms. All organisms in a food chain, except the first organism, are consumers.

A diagram on Food Chain - On Marine Life

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