Tecnologia

1- Analyze a typical structure from the “Delta de l’Ebre”: forces, loads, shape, materials. Can you see any bridge?

One of the most popular structure in Delta de l'Ebre is a house done by straw: it is called “Barracas”. It is built around the beginning of the 20th century. The loads basically in this house are: compression load in the walls, and tension load in the roof.

Draw:

The shape is very older, because we can see the roof with very slope, and is done by straw. 

The material used in this structure are: wood for hold the roof, reeds for help holding the roof, mud for do the walls, nets for hold the straw, and glass in the windows.

We can see some bridges,especially beam bridges like this:

2- Parts of a bicycle. Analyze your bicycle: how many plates and pinions have your bicycle? Which is the gear ratio of your bicycle? Do you think that the bicycle is a multiplying or a reduction system? Why?

Plates: 20

Pinions: 40

Gear ratio = N2/N1  = 40/20 = 2