miércoles, 29 de marzo de 2017

Matter and Force.

5º. Unit 7.Matter and Force.

Matter is everything around you. Atoms and molecules are all composed of matter. Matter is anything that has mass and takes up space. If you are new to the idea of mass, it is the amount of stuff in an object. We talk about the difference between mass and weight in another section. Matter is sometimes related to light and electromagnetic radiation.





Matter is everything around us. Matter is made out of tiny particles called atoms. Some atoms join together to make groups known as molecules.
Apart from its color, odor and tested, matter has other properties and can be found in three different states.


A physical property is any characteristic of matter that's observable. If you were to pick up an apple, how would you describe it? It's smooth, hard, red and tastes sweet. These are some observable properties.
In physics, the physical properties also include anything that can be measured. There are two very important physical properties:
  • Volume is how much space matter takes up.
  • Mass is the amount of atoms in a given object. (Atoms are the very tiny parts that make up matter, and the more there are, the more mass there is.)

It can be easy to confuse these two properties, but remember that volume is different than mass. A simplified way to think about it is that mass is weight and volume is size. Think of a brick and a large shoebox. The brick weighs more (has more mass) than the shoebox, but takes up less space (has less volume) than the shoebox.


Common Physical Properties

As we discussed, physical properties can be observable or measurable. Let's explore some of the common types of properties in each category:

Observable Physical Properties

  • Color
  • Size
  • Texture
  • Shape
  • Odor
  • Hardness
  • Physical state of matter (whether it is a liquid, solid, or gas) 
  • Measurable Physical Properties

  • Volume
  • Mass
  • Weight
  • Temperature
  • Freezing point
  • Boiling point
  • Melting point 


Chemistry / Pure and Mixed Substances

  • Matter can be classified as pure substances and mixtures.
  • Pure substances contains all the molecules of same kind whereas in mixtures molecules are different.
  • Mixtures can be separated using different techniques like winnowing, filtration, sedimentation, decantation, distillation .

Everything on Earth is powered by forces, pushes and pulls which act on our bodies and the things around us. Forces make things move and stop moving.
Some of the forces we are subject to are gravity (which keeps us on the Earth's surface), the centripetal force (the force that makes things move in circles) and friction (the force which makes things stick or slide).
Simple machines work by turning small forces into larger ones, allowing us to perform tasks with more strength or speed. Examples of simple machines are levers, gears, pulleys, wheels and screws.

What are forces?

A force can be a push or a pull. For example, when you push open a door you have to apply a force to the door. You also have to apply a force to pull open a drawer.
You cannot see a force but often you can see what it does. Forces can change the speed of something, the direction it is moving in or its shape. For example, an elastic band gets longer if you pull it.



All objects have a force that attracts them towards each other. This is called gravity. Even you attract other objects to you because of gravity, but you have too little mass for the force to be very strong.
Gravitational force increases when:
  • the masses are bigger
  • the objects are closer
Gravity only becomes noticeable when there is a really massive object like a moon, planet or star. We are pulled down towards the ground because of gravity. The gravitational force pulls in the direction towards the centre of the Earth.


miércoles, 8 de marzo de 2017


5º . Unit 6.          Biosphere.
 The biosphere is defined as the sphere or area around the planet Earth where life exists. This zone of life is vast. Most lifeforms live on or near the surface of Earth. However, some live deep within the hydrosphere (oceans, lakes and streams), while others thrive in the depths of the lithosphere (solid portion of Earth). For this reason, mapping the exact borders of the biosphere is quite challenging.
The biosphere is all about life. Physical geographers use the term biosphere to describe our living world. All of the microbes, plants, and animals can be found somewhere in the biosphere. The biosphere extends to the upper areas of the atmosphere where birds and insects can be found. It also reaches to dark caves deep in the ground or to the bottom of the ocean at hydrothermal vents. The biosphere extends to any place that life of any kind might exist.



Food Chain

Food Chain

Read more at: http://www.ducksters.com/science/ecosystems/food_chain_and_web.php
This text is Copyright © Ducksters. Do not use without permission.
Every living plant and animal must have energy to survive. Plants rely on the soil, water, and the sun for energy. Animals rely on plants as well as other animals for energy. In an ecosystem, plants and animals all rely on each other to live. Scientists sometimes describe this dependence using a food chain or a food web. Food Chain A food chain describes how different organisms eat each other, starting out with a plant and ending with an animal. For example, you could write the food chain for a lion like this: grass ---> zebra ---> lion The lion eats the zebra, which eats the grass.

 The Food Chain
Every living thing needs energy in order to live. Everytime animals do something (run, jump) they use energy to do so.

Animals get energy from the food they eat, and all living things get energy from food. Plants use sunlight, water and nutrients to get energy (in a process called photosynthesis). Energy is necessary for living beings to grow.
A food chain shows how each living thing gets food, and how nutrients and energy are passed from creature to creature. Food chains begin with plant-life, and end with animal-life. Some animals eat plants, some animals eat other animals.



Loss of Biodiversity

The main cause of the loss of biodiversity can be attributed to the influence of human beings on the world’s ecosystem, In fact human beings have deeply altered the environment, and have modified the territory, exploiting the species directly, for example by fishing and hunting, changing the biogeochemical cycles and transferring species from one area to another of the Planet. The threats to biodiversity can be summarized in the following main points:
  • Alteration and loss of the habitats
  • Introduction of exotic species and genetically modified organisms
  • Pollution
  • Climate change
  • Overexploitation of resources