ELECTRIC CIRCUITS-By Paula Pinilla and Ernesto Garcia

 Paula and Ernesto built two models, one of a house and one of a city. They used boxes, plasticine, card, plastic toys and anything they considered useful. They fitted electric circuits in their models , including different elements as light bulbs and switches. They fitted in a circuit in parallel in the house model. This way they could show how the elements of the circuit are independent from eachother. Due to this you can switch  the different light bulbs on or off, in different rooms independently. This is because circuits in parallel are made up of many circuits joined together and while some parts of the circuit are closed, (lights on), at the same time, other parts of the circuit can be open, (lights off).

 In the model of the city they fitted in a circuit in series. In this case there is only one circuit with many elements in a line. All the light bulbs are connected one after the other, including the light source or battery and the switch. This means that the entire circuit is either open or closed. If the circuit is open, all the light bulbs will be off and if it is closed all the light bulbs will be on.

 Both circuits have their advantages and their disadvantages depending on the needs in each case. Sometimes it is useful to be able to switch many elements on or off at the same time, using only one switch to do this, e.g Christmas tree lights. In other cases, it's better to be able to control the elements individually even if this means having different switches, e.g. in a house, we usually don't need to switch all the lights on or off, it's better to be able to control each room independently.

INTERACTION FUNCTION - EXTRA ACTIVITIES

If you've had problems with this unit and you would like to reinforce some of the concepts, you can do these extra activities. Hand them in as soon as possible so I can consider them for the next grade mark, I recommend Monday 15th February at the latest!

Write stimuli, receptor, coordination system, response and effector for the following situations.
a) A man hears music and begins to clap.
b) A zebra sees and hears a lion and runs away.
c) A boy touches a flame and pulls his hand away quickly.
d) The temperature goes up and  a man begins to sweat.
e) A chamaleon sees a predator and changes colour.

The Stirling Engine - By Laura Cózar

                          

 Laura's topic for the Science Fair was about the Stirling Engine. She made a stirling engine using a syringe, test tube, rubber (balloons) and marbles. The stirling engine was invented by Robert Stirling in 1790. Basically this engine converts heat energy into mechanical energy. The air in the syringe is heated by an external heat source e.g. Bunsen burner. When the air heats up it expands and the pressure in the syringe makes it go up, moving the marbles. Now most of the air is in the cold side and it contracts, the syringe goes down pushing the marbles again. If the engine is perfectly balanced the movement is constant. The movement stops by removing the heat source. This is an easy and safe way to produce movement and it doesn't pollute. Although it aslo has a few disadvantages, the need of always having to have an external energy source and the fact that it doesn't produce a very fast movement. 

 For the science class it's an excellent way to illustrate an energy conversion, how heat can be changed into movement! Laura did a great job with this topic, specially considering she had to make a last minute experiment change!

 This is Laura showing the class her experiment and practicing for the Science Fair.

                  

 This is Laura at the Science Fair.

The Smoke Machine!

                                 

 This experiment is a very effective way to show how much `dirt ' cigarrettes contain. Pablo Abad made a device to show this. Using plastic bottles and a vacum he was able to make what he called a smoke machine. On one side of the machine he inserted a cigarrete and on the other a vacumn that absorbed the air in the bottle and consequently smoked up the cigarrate. All the smoke was caught up in the bottle. In the centre he placed a small piece of filter paper. When all the cigarrette was smkoed up he would remove the filter and show all the `dirt ' that had stuck to it. Pablo repeated the experiment various times in the Science Fair and many, not only sudents, but also adults were very impressed to see what cigarretes contain and to think that all the horrible looking substances on the filter paper would end up in their lungs if they smoked. This experiment produced many reactions in the people that visited Pabl's stand. We hope that we have contributed to put off people smoking!

         This is Pablo making his smoke machine.

 For his panel pablo investigated what substances cigarettes contain. He was suprised to find that many chemicals in cigarettes are also used in other products as industrial solvents, batteries, plastic materials, detergents etc.

Watch the video to see how it works!

     Pablo at the Science Fair

ESO 1 STUDENTS - REMEMBER!

Don't forget to check ou the posts I suggested in class!

* IDENTIFYING MOLLUSCS. In this post you can identify some of the molluscs we've mentioned in class, like razor clams, scallop, cockles etc.
* CLAMS IN ACTION! Watch this video to understand how molluscs move and to see how they use their muscular foot to do this and to bury themselves in the sand.
* EXTERNAL AND INTERNAL FEATURES OF A CLAM. In this post you will be able to see in detail the different body parts of a clam, like the gills, the mantle and the muscular foot.

All you have to do is write the title of these posts in the search box.

Growing onions vertically!

This is a good way to grow onions at home if you don't have a garden or a lot of space. To grow onions vertically all you need is a 5 litre plastic container, soil and onions.
 All you need to do is carefully cut out circles in the plastic container. Then, fill the container with layers of soil and onions. Make sure the onions are near the openings, spray water onto the onions frequently and make sure the soil is always damp. Leave in a fairly sunny place.

 We prepared this experiment in the class and after only a few days, shoots began to appear from the onions. You can cut these shoots and use them in salads, you will see how they quickly grow back. Julio Urri did this is experiment for last years Science Fair.

GRADE EXAMS INFORMATION

In section ESO1 and ESO2, there is informaton about the dates and contents of the next grade exams. Check it out!