From the abacus and the first horse-drawn carts to the latest 21st-century gadgets, every invention requires the work of many people.

1. MANY MACHINES IN ONE

Four examples of simple machines in cars:

• Wheel and axle: We use them to move things across the ground more easily.

• Screw: We use them to hold things together or lift objects.

• Pulley: This machine has a wheel and axle and a rope. When we pull down on the rope, we lift an object that is attached to it.

• Lever and fulcrum: This machine is a rigid bar which turns on a support called a fulcrum. When we push one end of a lever down, the opposite end moves up.

When we put two or more simple machines together, we get a complex machine. Some machines also have an engine or a motor.

• Engines and motors: It is the part of the machine that produces movement.

• Gears: They are wheels with teeth that fit together. When one wheel turns the other one turns too, but in the opposite direction. We can find gears in windmills, clocks and watches, and toys with motors.

2. TECHNOLOGY INFLUENCES OUR LIVE

Technology changes how we do things and how we spend our time. New inventions can help us achieve better results and be more efficient.

2.1. PHONES

Phones allow us to write texts, watch films, listen to music, find information on the Internet, send emails, read newspapers and books, do the shopping…

2.2. SWITCHED ON AT HOME

We do domestic chores with the help of dishwashers, washing machines, microwave ovens and food processors. More examples:

• Freezers and refrigerators: We can keep food longer.

• Heating and air conditioning appliances: They allow us to control the temperature.

Energy-saving light bulbs: They provide a soft, warm, energy efficient light, with a very long life and reduced operating costs.

2.3. INDUSTRIAL CHANGES

Industries and many products damage our environment. Companies are developing new machines and materials which are environmentally friendly. Governments can also create laws to control industry.

2.4. EDUCATION

New technologies have also entered the classroom and changed the way students learn. Tablets, e-books and interactive whiteboards are the most common examples.

2.5. TRANSPORT

Travel time has been reduced by the development of high speed trains. Many vehicles now use alternative energy sources such as eco-fuel, bio-diesel, or solar energy.

2.6. FREE TIME

Whether you watch a film at home or at the cinema, you can enjoy spectacular special effects, computer-generated cartoons and films in three dimensions. Museums have interactive activities to make the visit more interesting.

2.7. HEALTH

X-rays, CT scans and ultrasound devices are examples of technology in hospitals which help detect diseases. There are devices to measure the level of glucose in blood for diabetic patients and devices that measure blood pressure.