https://padlet.com/mmardomingo8806/wq7yfunec2u en-us 2018-11-28 15:27:40 UTC 2018-12-02 15:23:54 UTC hello@padlet.com mmardomingo8806 https://padlet.com/mmardomingo8806/wq7yfunec2u/wish/308842708 Each of the chemical elements that are good conductors of electricity and heat, with a characteristic brigthness, solids at ordinary temperature, except for mercury
and that in their salts in solution they form electropositive ions or cations.]]> 2018-11-28 15:36:31 UTC https://padlet.com/mmardomingo8806/wq7yfunec2u/wish/308842708 mmardomingo8806 https://padlet.com/mmardomingo8806/wq7yfunec2u/wish/309719052 Tensile strength: It's good in the longitudinal direction and poor in the transverse direction.
Compresive strength: It's better in the transverse direction than in the  longitudinal direction.
Flexural strength: It's good, but better in the transverse direction. This is why it was used a lot in the past to make posts and beans.
Hardness: This can vary a lot. It depends on the type of wood, the structure and the cutting direction. Generally speaking, wood is not very hard and this makes it easier to work with. However it's hard enough to be sturdy, so it's used to build furniture, houses...
Toughness: Wood is tough, so it is used to make sport equipment like hockey sticks.
Thermal and electrical conductivity: It is very low.  Wood is an insulator of heat and electricity. This is why wood is used to make handles for tools.
Sound conductivity: Good. This is why it is used to make certain music instruments.
Colour: Woods have differemt colours:they can be white( pine) yellow( bow wood) dark yellow or brown(pear) red( alder) black (ebony)...The latter types of wood are prized for making furniture; woods  with less interesting colours are used in construction or to make tools with.
Density: Wood is a light material. It has lower density than water. This is why it is used to make ships.


]]> 2018-11-30 11:48:24 UTC https://padlet.com/mmardomingo8806/wq7yfunec2u/wish/309719052 mmardomingo8806 https://padlet.com/mmardomingo8806/wq7yfunec2u/wish/309832167 It enhances the properites of natural wood and reduces its price, although it doesn't look as attractive as natural wood. The most important types of man-made wood are chipboard and plywood
Plywood: Is formed by an odd number of thin wood layers  called veneers that are laid on top of each other and bonded with adhesive. The veneers are laid in alterning directions. This gives the plywood more strengthuniformity and stability The more veneers it has, the stronger it will be. Plywood is use to make table tennis, boats...
Chipboard: It is obtained from wood chipsthat are mixed with resin and then pressed. It is avaliable in sheets of different thicknesses. It can be coated with a thin plastic or natural wood veneer to enhance certain properties or improve its appearance. It is used in all types of furniture, in construction and in chairs and tables at schools.

]]> 2018-11-30 15:55:41 UTC https://padlet.com/mmardomingo8806/wq7yfunec2u/wish/309832167 mmardomingo8806 https://padlet.com/mmardomingo8806/wq7yfunec2u/wish/309886614 This are metals that contain mainly iron.
Iron: When the percentage of carbon in the alloy is less than a 0.1 percent, we call this material iron. pure iron is soft, ductile and malleable. It rusts easily because it has a low concentration of carbon. It's also very brittle. As a result, it is only used in medicine and electronics.
Steel: It's made mainly from iron with 0.1 to 2 cent of carbon. Because it has higher proportion of carbon, it's harder than iron. Steel is fairly inexpensive and is widely used in industry. Steel alloys are a special type of steel. They are composed of iron, carbon and small amounts of other elements. They are very resistant to rust, high temperature and wear.
Cast iron: It's made from iron and 2 to 6.67 percent of carbon. It's used in the manufacture of engines, machine structures, tools, manhole covers...]]> 2018-11-30 17:33:43 UTC https://padlet.com/mmardomingo8806/wq7yfunec2u/wish/309886614 mmardomingo8806 https://padlet.com/mmardomingo8806/wq7yfunec2u/wish/309903190 This are metals that don't contain iron.
Cooper: It's a red-coloured metal that has been used since ancient times. The oldest cooper object that we know is a small ornament that dates from 9500 BC.
It's a very good conductor of heat and electricity.
It's highly resistant to corrosion.
It's very ductile and malleable, and easy to solder.
Cooper is used to make wires, water and gas pipes... It's also used  a lot to make alloys with metals such as tin and zink.
Tin: It's a silver-coloured shiny metal.
It's very resistant to corrosion. 
It's very ductile and malleable when cold.
It's very easy towork with and to melt. It's used as a filler metal for soft soldering.
Tin is non-toxic so it is used to coat steel or iron to make tinplate , wich is widely used in the manufacture of tin cans.
It is combined with cooper to form bronze, wich is a strong, hard metal that is almost as hard as steel. In addition, because it has excellent sonorous qualities, it is also used to make bells.
Aluminium: It is the third most common element in the Earth's crust.
 It is white, shny, very light, cheap and easy to recicle.
It's resistant to corrosion.
It is a very good conductor of heat and elctricity.
It is non-toxic, so it is used in food packaging.
It is very ductile and malleable.
It is easy to shape.
It has many varied uses, including drink cans, high voltage power lines and airframes for aeroplanes.
Zink: It is a bluish-white in colour and is one of the least common metals.
It is malleable and ductile.
It is a good conductor of heat and elctricity.
It is highly resistant to corrosion and rust.
It is usually used to protect other metals from rust (mainly iron and steel). Metals with a zinc coating are resistant to weathering.
Onother of the main applications of this metal is an alloy with cooper to make brass. Brass is twice resistant as strong as the pure metals that make it and it has a characteristic shine similar to the one from gold.]]> 2018-11-30 18:05:54 UTC https://padlet.com/mmardomingo8806/wq7yfunec2u/wish/309903190 mmardomingo8806 https://padlet.com/mmardomingo8806/wq7yfunec2u/wish/310167366 They include man-made wood and wood derivatives]]> 2018-12-02 14:59:07 UTC https://padlet.com/mmardomingo8806/wq7yfunec2u/wish/310167366 mmardomingo8806 https://padlet.com/mmardomingo8806/wq7yfunec2u/wish/310167645 They are usually obtained from leftover wood. The most common ones are paper cardboard and cork.
Paper: It is obtained by forming a paste out of wood and plant fibresthat is mashed, pressed and then dried. It is easy to cut, paste and fold, but it is not very strong and it breaks easily. Additives can be used to bleach it or give it a different texture. Sheets of paper are used for writing on and to make envelopes, books, wrappers...
Cardboard: It is made by compressing several layers of paper while it is wet to thicken it and produce a heavier texture. It is thicker than paper so it is stronger and not as easy to work with. It is most commonly used to make boxes for packaging.
Cork: It is obtained from the bark of the cork oak. Itis waterproof, lightweight material and a very good insulator of electricity, heat and sound. It is used in bottle stoppers, as insulation, for notice boards... ]]> 2018-12-02 15:01:30 UTC https://padlet.com/mmardomingo8806/wq7yfunec2u/wish/310167645