FORCES AND MACHINES

UNIT 5. NATURAL SCIENCE.

We explore forces and machines

INDEX

Great inventions

Frontpage

Introduction

10

Machines in daily life

Big questions

Forces

11

Project

Mind map

Machines

12

Self-assessment

Glossary

History of machines

BIG QUESTIONS

1. What is force amd what types of forces are there?

2. What is a simple machine?

3. Which are the three types of simple machines?

4. Which inventions do you think changed history?

5. Can you give examples about machines which we use every day?

3.

MIND MAP

4.

GLOSSARY

The inventions and discoveries that changed history

Forces

Machines

History of machines

Machines in daily life

5.

INTRODUCTION

Many inventions make a difference to our lives. In Prehistory, people used sticks and rocks. Today , we have all kinds of electronic devices. Inventions make life easier for everyone.

How can we promote great inventions?

6.

FORCES

What are forces?

A force is a pull or a push on an object. When we push a trolley or pick up a book, we use force.

The effects of forces

Types of forces

There are two types of forces:

A non-contact force acts at a distance. Two objects interact but do not touch each other.

A contact force happens when two objects touch each other

Types of non-contact forces

7.

MACHINES

What are machines?

A machine is a device that does a task. It makes our lives easier and saves times. Some machines, like spaceships, allow us to do things that are impossible for humans to do alone.

Machines and energy

Light energy is the energy found in a light source, like the Sun. Plants use energy from sunlight to make their food.

Chemical energy is the energy stored in food, fuels and explosives.

Electrical energy is the energy found in lightning. it comes through cables to our homes.

Mechanical energy is the energy that an object has because of its motion and its position. Sound has mechanical energy

Simple machines

These are the most common simple machines:

Pulley

• A pulley is a wheel with a rope or a chain around it. We use to lift heavy objects.

• Pulleys change the direction of the force. Pulling down one end of the rope creates an upward pull on the other end.

Inclined plane

• An inclined plane is a ramp used to move objects up and down more easily.

• We use less force to move an object, but we use the force over a longer distance.

Lever

• A lever is a solid bar that turns on a fixed point of support.

• When we use a lever there is fulcrum, a load and the force.

• There are three types of levers

Types of levers

8.

HISTORY OF MACHINES

How have machines changed?

Machines have changed a lot throughout history. This is because of scientific discoveries, technical improvements and the use of new materials and energy sources

The history of machines

The first machines were very imple. They were made of stone, wood, bone, leather,rope, etc...People made them move.

Steam engines used coal. These machines were powerful and efficient

Machines improved when people started using metal tools.

Today, most machines use electrical energy or fossil fuels. We use many new materials . We can use computers to program machines so that they work automatically.

9.

GREAT INVENTIONS

THE PRINTING PRESS

Johannes Gutemberg invented the printing press in the 15th century. This made it possible to print books, instead of copying them by hand

THE STEAM ENGINE

The steam engine uses energy from coal to make factory machines and vehicles work. James Watt created the steam engine in the 18th century.

ELECTRICITY

Many scientists explained how to use electrical energy. Inventors like Thomas Edison and Nicola Tesla applied their knowledge in the late 19th century and early 20th century.

THE RADIO

At the end of the 19th century , Guglielmo Malconi created a system to send signals without cables. This made it possible to develop radios, televisions and mobile phones.

THE COMPUTER

The first computers were made in the mid-20th century. They filled an entire room. Today, computers fit inside a mobile phone

10.

MACHINES IN DAILY LIFE

How do we use machines in our daily life?

Machines and technology have changed the way we live in many ways. Today ,our lives are very different from the lives of our ancestors.

Communications

Transport

Work

• With new machines, products can reach every corner of the world.

• People can travel long distances in short periods of time

• Before electricity was developed, people or horses carried messages.

• The telephone and the Internet allow us to communicate instantly. We can send emails and make video calls.

• Machines can do difficult and dangerous jobs

• Some machines, such as industrial robots can do the work of many people.

• Computers and electronics have also changed the way we work in offices

At home

Culture and leisure

Health

• Appliances , such as the fridge, allow us to keep food longer and in better conditions.

• Other appliances, such as the washing machine, make our daily tasks easier.

• We live longer and better today thanks to inventions in m30edical technology.

• There are also techniques, like X-rays and ultrasound, that allow usto see inside the human body.

• Films, radio and television changed culture and entertainment in the 20th century.

• Today, the internet offers new ways to create and share. It also gives us new types of entertainment

11.

PROJECT. MAKE A SIMPLE MACHINE

Thank you!

All machines require energy to work. There are different forms of energy:

Guglielmo Marconi

• Many forces repel objects. For example, when we kick a ball, the ball moves away from us.

• Other forces attract objects. For example, a magnet pulls on objects made of iron.

• Gravity is a non-contact force . It attracts all objects towards the centre of the Earth.

James Watt

Forces can break objects.

Forces can make objects stop moving.

Forces can make objects start moving.

Forces can make objects change shape.

Johannes Gutenberg