machinery

Machinery

Machinery
Machinery divided into simple and complex mechanical machinery.

Kind of simple machines include lever, inclined plane, wedge, screw, axles, pulleys and gears.

Simple Machines

lever

When we use the iron spoon biscuit barrel lid open, we applied the principle of leverage. Leverage is a rotation around a hard baton's fixed point . There are three important lever position, that is the focus, the fulcrum and the power point. Scissors, shelves and broom are references to the principle of leverage.

Lever also divided into three categories:

The first class lever, the fulcrum is positioned between the focus and priorities. For example: scissors, hammers, spoons (to open the lid) and pliers.

The second class lever, located at the midpoint between the fulcrum and the power point. For example: cutter, trolleys, nutcracker and bottle opener.

Between the third class lever, the force point and the focus and fulcrum. For example: clip the ice, fishing rod, mops and staplers.

Slope

The inclined surface. To lift a heavy object would cost a lot of power, but if you push the same weight along an inclined plane, the force required on a small lot. The longer the slopes on the slope of the smaller weights to put more time and effort to run uphill. Stairs, ladders and road (ramp) on the slopes of the principles are applied ramp.

Wedge

Wedge by at least one inclined surface thereof. Wedge has two ends, one end of a thick, thin the other end. It uses force to split, drilling or cutting objects. Harmonious face, like a wedge longer, thinner, more effort. Knives, axes and saws are applications of the principles of the wedge.

spiral

An inclined plane wrapped around the cylinder of simple machines is called spiral. Screw spiral principle of operation, can the two objects fitted together. Thread more dense, more effort. Screw, crane screw cap and screw taps are applied principle.

axle

Right wheel axle and axle components. Where there is a mechanical application of the principle of the wheel axle to operate. Some machines Although there is no wheel, only the axis, but it is the application of the principles of the axle to exercise, because it replaced the crank wheel. When the axle for moving, rotating wheel will follow. Tires, door handles and pulley are applications of the principles of the hub.

pulley

There are types of pulley fixed pulley, pulley and pulley block.

Fixed pulley is fixed in one position without moving the rotating pulley. Fixed pulley to change the direction of the force, but not effort.

Movable pulley can be moved together with the pulley weights. Movable pulley can not change the direction of the force, but it can and effort.

Pulley block is fixed pulley and the pulley together. Pulley block not only change the direction of movement of the object, but also effort.

Gear
gear is neat edge toothed wheel. We turn a gear to drive another gear, the gear change the direction of movement of the object, but also to speed up or slow down the speed of the object. When the large gear to rotate in a counterclockwise direction, it will drive pinion in a clockwise direction. When the revolution of the large gear, a pinion gear is driven to rotate twice, because this is smaller than the pinion gear.
The two separate gears, connected by a chain. When the large gear to rotate in a clockwise direction, will lead to the same pinion is rotated in a clockwise direction. Watches, alarm clock and bicycles application of the principles of the gear.


Fried complex mechanical
complex machinery refers to two or more simple machines.

Nail clippers and application of the principle of the lever of the wedge.


Whisk the application of the principles of axles and gears.


Pencil sharpener applied axle, wedge and screw the principle.


Cutter application and leverage the wedge principle.

microorganism

Microorganism
Microbial divided into five categories: fungi, protozoa, algae, viruses and bacteria.

Microorganism can breath, multiply and move.

Fungus
Living in a variety of soils and decaying material. E.g:

Yeast












Mucor



Mold


Protozoan
Most live in the river, sea, ponds and moist soil. Eats bacteria and algae. E.g:

Paramecium


amoeba


Alga
The ocean and pools and other wet and sunny place are their place to live. Get to carry out photosynthesis like plants.

Plankton


Spirogyra
 

Virus
Varied shapes, the smallest. Need to rely on other organisms to survive, such as protozoa, bacteria, animals and humans. E.g:

Ebola


Influenza virus


HIV


Bacterial
The largest number in any place exists. E.g:

E. coli


Bacillus


salmonella


Streptococcus


Things that will affect microbial's growth conditions
1. Water
2. Air
3. Nutrients
4. The appropriate temperature
5. The proper acidity

Microbial advantages and disadvantages

Benefit
Food Production: Bacillus can be used to make a delicious and healthy yogurt; yeast can be used to make bread.

Decomposition of organic materials: Waste water must be purified before getting discharged into the river, sea and lake. The microorganisms such as protozoa and bacteria in waste water is added to purify waste water; bacteria and fungi can break down the bodies of animal and plants that have withered, so as to provide organic fertilizer for the soil, so the soil will be more fertile.

Protection of human health: Bacteria and fungi can be made of antibiotics for the treatment of bacteria should have also made the disease; the vaccine is made from viruses and bacteria, through vaccination, the body's ability to resist the virus because It should be sent disease.

Harm
Cause various diseases: Bacteria and viruses can cause a variety of diseases such as chicken pox, foot and mouth disease, pharyngitis, and measles.

Cause tooth decay: the acidic substance adheres to teeth produced by bacteria will damage our teeth.

Food spoilage: if the food is not stored properly, can easily grow bacteria and fungi.

Cause food poisoning: If you accidentally eat fungal or bacterial contamination food.












Challenge yourself
1. What is the smallest microorganism?

2. What will affect the growth of microorganisms?

3. List out three bacteria types.

4. Name two characteristics of the virus.

5. What are the benefits of yeast?

6. Write three benefits of microorganisms.

7. Write three disadvantages of microorganisms.