LEARNING ABOUT THE COMPUTERS

Watch the video below to learn about computers:

Computing system: hardware and Software

In this video, you’ll learn about the basic parts of a desktop computer.
 

 What's inside the computer?

 

STRUCTURAL CONDITIONS

• STABLITY: the capacity of a structure to remain uprighy and not  fall over. A structure's centre of Gravity must  be centred over its base and close to the groud for it to  be nmore stable.

Have a look next  video  in Spanish, in which you  can learn  how to  find it  in simple objects or the difference between  the gravity Centre in men and women.

• RESISTANCE
• RIGIDITY

Strong Structures with Triangles

Why the triangles are very important for make a structure stable:

MECHANISM

Mechanisms allows objects to  move. They  transmit and transform force and motion from a motor to a  a receptor. They  make work easier and more comfortable for human  beings.

• Linear transmission of  motion: 
• Levers

Class 1	Class 2	Class 3
It has the turning point(fulcrum) between the load and the effort.	It has the load between the fulcrum and the effort	It has the effort between the fulcrum and the load

Have a look the next videos about levers: 

what is a lever? 

  

Types of levers:

 

 


• Pulleys:
  The pulley is a simple machine made with a wheel and a rope or chain. There are three types of pulleys: 
  
• Fixed pulley: The pulley is balanced when the force we apply F is equal the load R.
• Movable pulley: It`s a set of two pulleys, one fixed and another with  linear  movement
• Compound pulley system: a special combination of fixed and movable pulleys. 

            Examples of pulleys: Elevators, gym equipment, wells, curtains at a theatre, blinds on the windows, the clotheslines, flagpoles to hoist the flag up or to bring it down, cranes, garage doors raise and lower utilising a pulley system, rock climbers use pulleys to help them to climb, timing belt in cars...

pulley to climb

Timing belt in cars

       







Watch this video about pulleys:

• Rotary transmission:
• Friction wheels



pulley with belts

• https://youtu.be/04jEqln4SRI 
• Pulleys with  belts
• https://youtu.be/LVro9AMkPAU 
• Gears
• https://www.youtube.com/watch?v=sg9AjzaD7Ts&feature=youtu.be
• Sprockets with chains 
• http://www.technologystudent.com/gears1/chain1.htm 

•   Transformation of motion: 
•  Winch and crank mechanism

• Rack and pinion mechanism 
•  http://www.technologystudent.com/gears1/gears4.htm
• http://www.technologystudent.com/gears1/drlgear.htm
• Crank and Rod mechanism 
• https://youtu.be/ZO8QEG4x0wY 

FORCES AND LOADS

When a force acts on a structure, that force becomes a load to the structure. 

A typical load that acts on a structure is it's own self-weight or gravitational force. Your own body weight is a load on your skeleton.

There are basically two types of generic loading on a structure:

•  Permanent load: it doesn't vary over the time (e.g. own weight).

•  Variable load: it varies over the time (e.g. weight of snow).

Stress (internal force) is a force that appears when a structure receives an external force. 

There are typically 5 different types of stress:

    a) Tension
    b) Compression
    c) Shear
    d) Bending
    e) Torsion

TYPES OF STRUCTURES

A structure is a set of elements arranged in an optimum way to support a body or an object.

The structure of an object is the ordely distribution of its essential part. This is what gives the object its shape.

Most large structures are one of the following types: mass, frame, truss, vaulted, shell, geodesic or pneumatic.

In the next  video  you  can see examples of the different  types  of structures.

ALLOYS

Alloys are a mixture that contains at least one metal.

• It can be two or more metals such as Bronze: Copper + Tin
• It can be a metal and non metal  such as  steel: Iron + Carbon 

The product we obtain from the mixture may  have a property that the original components did not  have. This makes alloys very  useful.

Alloys compared to pure metals:

• Alloying increases strength and hardness.
• Alloying reduces malleability and ductility.

The first alloy created by  humans was bronze, which is harder and stronger  than  its components. 

Find out  more about bronze: http://www.makin-metals.com/about/history-of-bronze-infographic/