Technology Department I.E.S. El Molinillo

Guillena

© ANTONIO JESUS ROMEROJUAN ANTONIO TIERNO NICOLAS

The characteristics of the materials are those that make the materials have different reactions to heat, electricity, light, force…If you know these characteristics you can choose their aplications.

Traditional Materials

Ferrofluído

Grafeno

New Materials

Density: The relationship between mass and volume.It is the mass per unit volume of a material.d=densitym=massV=volume

The cork and the lead have got the same mass. But the lead has less volume because it is more dense.

Which is more dense?

Higroscopic materials absorb water as for example cellulose and silica gel.

The materials that are little higroscopic are used to make waterproof tests.

The materials with a good thermical conductivity are the metals.

Plastics, ceramics , wood and cork are good thermical insulators.

The temperature of the materials is in relation to the speed of vibration of his particle.

When we heat one edge of a conductive material, atoms vibrate faster and when they crash into one another, the heat is transferred along the material.

Heat transmissionHotter

less hot

Dilation Coefficient: It is to increase the volume that is produced in the materials with temperature changes.

The expansion joint is very important to keep variable size in a structure.

expansion joint

The metals are good electricity conductivesThe plastics are good insulators.We make insulated electric cables with metal and plastic mixtures..The semiconductive materials (used in electronics) are insulating and the conductives ones depend on circumstances.

Hardness: it is the resistance to be scratched or penetrated. The opposite of hardness is softness.

Tenacity: It is the measure of strength of materials have to take knock without crash. The opposite of tenacity is frailty.

Soft materials are tenacious.

Ductility: It is the ability that objects to spin when they are in tension.

Malleability: mechanical property of objects to be made sheets by pressureIt.

Compression Traction

Flexion Torsion Shear

To know the characteristics of the materials is necessary to prove them.These proofs are called “To testing”.It is necessary to make material samples in order to verify the proofs.The samples of the materials are called cylinders.

A traction testing in steel cylinders.

A compression testing in a cement cylinders.

© ANTONIO JESUS ROMEROJUAN ANTONIO TIERNO NICOLAS