The Light

Light

Light moves in a straight line. It goes straight to an object.
Light moves very fast. The speed of the light is considered around 300,000 Km/s (three hundred thousand kilometers per second).

Light is responsible for the sense of sight. It is known as Visible light. Visible light is emitted and absorbed in tiny "packets" called photons.

Some objects do no let light through. When light cannot travel through an object, appears a shadow.


The shadow of an object always appears at the other side of the source of light. Look at the pictures: Where is the focus of the light in each picture?

 


COLOURS

The light we get from the Sun is called white light.

White light is a mixture of seven colours: red, orange, yellow, green, blue, indigo and violet.
We can see all these colours in the rainbow (when the light travels through the raindrops) or when the light passes trhough a prism.

Watch this video:



We can classify objects depending on how much light can pass through them:

• Transparent objects: clear glass allow light to pass through.
• Translucent objects: allow some light to pass through and we cannot see objects behind them very clearly. Some liquids ar translucent.
• Opaque objects: These objects do not allow light to pass through such as cardboard or wood.

Have a look to this video: 

Some objects can give light (they are a source of light). We call them luminous bodies. We can distinguish between Natural luminous bodies and Artificial luminous bodies (made by humans).

Non-luminous objects cannot produce light Most of them only reflects the light that reaches them.

Different Ecosystems

Differences between an Ecosystem and a Biome



        An Ecosystem describes a specific area where the organisms (living things and non-living things) interact together as a unit. It can be very small like a swiming pool with water or it can be so big as a desert or an ocean. Each ecosystem is different and each each individual plant, animal or non-living thing is important to the rest of the components of this ecosystem.

• All living organisms need millions of other living organisms to survive. The sun, soil, water, air, minerals, rocks, animals and plants need each others.

• The sun provides the energy needed by ecosystems. Plants take this energy and use photosynthesis to make their own food (energy). Nutrients in the soil, the air, and water also play a part in keeping an ecosystem thriving and in balance. 

       A Biome is the name to describe a large group of similar ecosystems. Biomes have similar weather, rainfall, animals, and plants. There are a number of biomes on planet Earth. See the map of the world biomes below.









Now we are going to talk about them. Click on the biomes below to learn more about each one.

Land Biomes
Desert
Grasslands
Savanna
Tundra
Tropical Rainforest
Temperate Forest
Taiga Forest

Aquatic Biomes
Marine
Freshwater
Coral Reef

Humans and the Ecosystem 

Humans have adversely affected many ecosystems and biomes throughout the world. Cutting down trees, developing land, growing crops, burning fossil fuels, overfishing, and overhunting are just some of the ways that we have upset the balance of nature.





Information obtained from http://www.ducksters.com/science/ecosystems/world_biomes.php

Ecosystems

What is an ecosystem?

An ecosystem is a place and the living things that live there.

An ecosystem is made up by:

• Living things: They born, grow, eat, breathe and reproduce.  We have two big groups: Plants and Animals.
• Non-living things: do not eat or grow. They are for example: air, water, soil, minerals...

 Audio
 (If you cannot open the sound file, download the VLC program here: download VLC )

There are big ecosystems like the savannah, the desert or the oceans. Even the Earth (our planet) can be considered the biggest ecosystem.






Other ecosystems are small like a pond or a river.




An ecosystem that we can find near of us is the Forest ecosystem: In a forest, there are plants like trees, bushes and grasses. There are insects and other kind of invertebrates animals such as beetles, ladybirds, butterflies, worms or spiders. There are vertebrates animals like squirrels, birds, mice, deers, owls or wolves.

 Other very common Ecosystem is the Sea: It is the biggest ecosystem of the Earth. In the sea, there are plants like seaweeds, invertebrates animals such as jelly fishes, crubs, mussels and octopuses; even vertebrates animals like fishes, dolphins and whales. Almost all of them live in the high sea. In the deep sea there are very little food, so very few animals can live there.





            In an ecosystem is very important the FOOD CHAIN or FOOD WEB: It is when an animal eat other animals or plants and it is eaten by other animals bigger. For example: herbivores animals (like rabbits) eat plants, carnivores animals (like eagles or hawks) eat this herbivores animals (rabbits) and some of these carnivores animals are eaten by other carnivores bigger.






The best video filmed by a tourist:

The same video translated to spanish

Activity to use in class with the Interactive Digital Board (IWB)

Here there is an activity for teachers to use in Science class with the Interactive WhiteBoard, as well known as Interactive Digital Board. This activity is created by two teachers at CRP Sant Martí, Barcelona during year 2012-13. To download the file, click the picture or the link below.

https://www.dropbox.com/s/8gthhw8nhhplclu/Ecosystems_science_project.notebook

Videos to watch and learn.

Now, you can watch some videos about it to obtain more information.

Video about ecosystems and food chains.

Video about components of the ECOSYSTEMS

http://www.youtube.com/watch?v=MWPj2IkeklI

Here you are a video in Spanish.

in Spanish: http://www.youtube.com/watch?v=tPFGdTE_nas