Soaps and detergents are made from long molecules that are water-loving at one end and grease-loving at the other end. When they go to work on dirty cloth, they surround each droplet of greasy dirt stuck to the fibres of the cloth with their grease - loving tails plugged into the grease droplet. The coated droplet then floats off the cloth into the water and is washed away.
How are chemical made ?
The chemical industry makes chemicals by processing raw materials with heat, pressure and chemical reactions. Sulphuric acid is made from sulphur in a series of stages that change sulphur into different compounds, ending with sulphuric acid.
Which trees produce cones ?
Tree that produce cones are called conifers. Conifers often grow as large trees which are themselves cone-shaped in outline. Cones are the parts of the conifer used for reproduction, so there are male and female cones. Male cones produce pollen which is carried by the wind to fertilise the female cone. This then develops and matures. Seeds form between the hard, protective scales of the cone and are released when ripe.
Tree Cones
How is loudness measured ?
Loudness depends on the amount of energy carried by a sound wave. The loudness of sound is measured in decibels (dB). Sounds louder than 120dB can damage the ears. Sounds louder than 130dB cause pain. Some animals, like bats, make sounds that we cannot hear at all.
Why are seaweeds slimy ?
Seaweeds are simple plants that grow on the seashore. There are lots of different types but most feel slimy to the touch. This is because there is a jelly-like layer on the seaweed surface. This keeps the plants supple and prevents the seaweed from being damaged by the waves.
SeaWeeds plants pictures
Credit : sintef.no
What are fungi ?
Fungi belong to a group of organisms separate from plants and animals. Unlike plants, they have no green pigment and cannot make their own food. The main part of a large fungus is a huge network of tiny threads in the ground. These take up food from dead plants and animals in the soil. At certain times of year, mushrooms and toadstools spring up from the threads and scatter spores that will grow into new fungi .
Fungi Mushroom pictures
Credit:k12.in.us
What causes the winds ?
Winds are created because of difference in air temperature and air pressure. When air heated at the equator, it rises, cools, and then sinks over the tropics. Some moves back again towards the equator, creating the trade winds. The rest is drawn towards the poles as westerly winds.
What is energy conservation ?
We use a lot of energy in our homes. Much of it comes from oil, coal or gas, which are fossil fuels that will one day be used up. If we insulate our houses better, and trap the Sun's heat, we use less fuel. This is called energy conservation. We also use ever-lasting energy sources, such as wind.
How ate magnets made ?
An iron bar contains molecular magnets pointing in all directions. If the bar is placed inside a coil carrying an electric current, the molecular magnets line up with the coil's magnetic field. The bar has now become a magnet.
What is a magnetic field ?
A magnetic field is a region of forces that exists around a magnet. The field can be drawn as a series of curved lines, called lines of force, joining the magnetic's north and south poles. The Earth behaves like a magnet. Its magnetic field, caused by electric currents inside the liquid part of its core, stretches thousands of kilometres into space.
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