UNIT 8

FORCES

PUSHING AND PULLING

-         When we apply force to an object, we push or pull that object.

-         A force always acts in one direction.

USING FORCE

-         We use forces to do many things every day.

-         For example: to open or close a door or a window.

-         We need to apply more force to move heavier objects.

DIFFERENT TYPES OF FORCES

CONTACT FORCES

-         When one object touches another object, the objects are in contact.

-         When one of the objects pushes or pulls the other object, there is a contact force.

GRAVITY

-         Gravity is a force that attracts a smaller object to a larger object.

-         All objects that have mass are affected by gravity.

-         Gravity keeps the Earth and the other planets in the Solar System in their orbits around the Sun.

-         Without gravity, everything would float into space.

MAGNETISM

-         Magnetism is the force that magnets produce.

-         Magnets attract some metals like iron.

-         The ends of a magnet are called poles.

-         Magnetism has two directions. It can pull objects together or away from each other.

MACHINES

MACHINES ARE TOOLS

-         A machine is a tool that makes work easier.

-         There are two types of machines: simple machines and complex machines.

-         Complex machines are two or more simple machines working together.

WORK

-         When we use a force we are doing work.

-         Pushing, pulling and lifting are examples of work.

SIMPLE MACHINES

LEVER

-         A lever is a bar that moves on a point called fulcrum that helps us to move heavy things.

PULLEY

-         A pulley is a wheel with a rope that helps us to lift heavy things.

INCLINED PLANE

-         An inclined plane has an angle that reduce the force needed to move  something up or down.

SCREW

-         A screw is an inclined plane around a shaft that helps us to joint different parts.

WHEEL AND AXLE

-         A wheel spins around and axl and helps us to move objects.

WEDGE

-         A wedge is made of two inclined planes.

-         We use wedges to cut or separate things.

SIMPLE AND COMPLEX MACHINES

-         Complex machines are two or more simple machines working together.

-         A bicycle is an example of a complex machine:

o   Screws are used to joint the parts.

o   The pedals are examples of a wheel and an axle…

7 UNIT

MATTER AND ITS PROPERTIES

-          Matter is anything that has mass and space.

DESCRIBING  MATTER

*Matter has four properties:

-         Size: big or small.

-         Shape: regular or irregular.

-         Colour: blue, red, yellow.

-         Texture: rough or smooth.

*We can measure length, volumen and mass:

-         Length: If an object is short or long.

   We measure length in metres.

-         Volume: Is the space an object occupies.

   We measure volume in litres.

-         Mass: If an object is heavy or light.

We measure mass in grammes and kilogrammes.

THE THREE STATES OF MATTER

We can find matter in three different states:

SOLIDS

-         Solids have a definite volume and shape.

LIQUIDS

-         Liquids have a definite volume, but they don´t have a definite shape.

-         They take the shape of their container.

GASES

-         Gases don´t have a definite volume or shape.

-         They take the shape and the volume of their container.

NATURAL AND MAN-MADE MATERIALS

NATURAL MATERIALS

*We find naturals materials in nature.

-         Minerals

o   We find minerals in rocks.

o   We use them as fuel, to make other materials like glass…

-         Wood

o   Wood comes from trees.

o   We use it, to make different things like paper and furniture.

-         Cotton

o   Cotton comes from the cotton plant.

o   We use it to make textiles and clothes.

-         Crude oil

o   We find crude oil underground.

o   We use it to make petrol, plastic…

-         Leather

o   Leather comes from animal skins.

o   We use it to make clothes, shoes…

MAN-MADE MATERIALS

*We can transform  naturals materials.

When we transform a natural material into another, we make man-made materials.

CHANGES IN MATTER

PHYSICAL CHANGES

-         When we change size, colour or shape we are making physical changes. For example, when we cut a piece of paper.

MIXTURES

-          Mixture are two or more kinds of matter that can be separated. For example, when we make a salad.

CHEMICAL CHANGES

When we transform one material into another, we make a chemical change. For example, when we burn wood

UNIDAD 7

LA MATERIA Y SUS PROPIEDADES

-          La materia es aquello que tiene masa y ocupa un espacio.

DESCRIBBIENDO LA MATERIA

*La materia tiene cuatro propiedades:

-         Talla o tamaño: grande o pequeño.

-         Forma: regular o irregular.

-         Color: azul, rojo, amarillo...

-         Textura: rugoso o liso.

*Nosotros podemos medir:

-         Longitud: Corto o largo. Lo medimos en metros.

-         Volumen: Es el espacio que un objeto ocupa. Lo medimos en litros.

-         Masa: Pesado o ligero. Lo medimos en gramos y kilogramos.

LOS TRES ESTADOS DE LA MATERIA

Tres estados:

SOLIDOS

-         Los sólidos tienen un volumen y forma definidos.

LÍQUIDOS

-         Los líquidos tienen un volumen definido, pero su forma no.

-         Cogen la forma del recipiente en el que se encuentran.

GASES

-         Los gases no tienen ni el volumen ni la forma definidos.

-         Cogen la forma y el volumen del recipiente que los contiene.

MATERIALES NATURALES Y MATERIALES HECHOS POR EL HOMBRE

MATERIALES  NATURALES

-         Minerales

o   Encontramos los minerales en las rocas.

o   Los usamos  para hacer otros materiales como cristal…

-         Madera

o   La madera proviene de los árboles.

o   La usamos  para hacer otras cosas como papel y muebles.

-         Algodón

o   El algodón proviene de la planta del algodón.

o   La usamos  para hacer tejidos y ropa.

-         Petróleo

o   Encontramos  el petróleo bajo la tierra.

o   Los usamos  para hacer combustible, plástico…

-         Piel

o   La piel proviene de la piel de los animales.

o   La usamos  para hacer ropa, zapatos...

MATERIALES HECHOS POR EL HOMBRE

*Podemos transformar  los materiales naturales en otros diferentes que son hechos por el hombre. Por ejemplo, la madera en papel.

CAMBIOS EN LA MATERIA

CAMBIOS FÍSICOS

-         Es cuando cambiamos el tamaño, color o forma.

-         Por ejemplo, cuando cortamos un trozo de papel.

MEZCLAS

-         Es cuando mezclamos dos o más cosas.

-         Por ejemplo, cuando hacemos una ensalada.

CAMBIOS QUÍMICOS

-         Es cuando transformamos un material en otro.

Por ejemplo, cuando quemamos madera.