Separating mixtures

We can do so many experiments in this chapter. I ever done such two of the experiments. I will give some experiment that showing the examples of separating mixtures. If you want to do it, sure you can!

1. When some solids are added to a container of water, they do not dissolve. They are insoluble in water. An example of this is sand mixed together with water. We can separate this type of mixture by decanting and filtration.


Decanting  is the separation of an insoluble solid from liquid by pouring away the liquid and leaving behind the solid.

Filtration is the process of separating small, insoluble solids from a liquid using filter. A filter is a semi-permeable  material which only allows some substances to pass through it but not others.


2. To separate a mixture, we need to know the substances the mixture is made up of first. We also need to know properties of these substances. We can then determine the correct technique to separate the mixture. Take a look at the examples:

- Add some water to a mixture that containing sand and salt. Then, stir well to dissolve all the salt.

- Filter the mixture using a funnel lined with a filter paper to separate the sand from the the saltwater. Leave the sand on the filter paper to dry. Sand is obtained.





-Heat the beaker containing the saltwater over flame to evaporate the water.





- When all the water has evaporated, the salt can be obtained.


I only have that kind of examples. If you wanna try, please be very careful when you turn on the fire..... :D

Physical and Chemical changes

Physical changes is a change only appearance of a substances. Changes in appearance include change in texture, shape, and size. A physical changes may or may not involve a change in state. No new materials are form in physical change. The example of physical change.


*Inflating the balloon  :         

  When we blow air into a balloon, its shape and size change. The material use to make the balloon does not change. It is still made from rubber. No new materials are formed.

 *Breaking glass: 

 When a drinking glass breaks, it turns into smaller pieces. Its shape and size is change. The material used to to make the drinking glass does not change. It is still made from the glass. No new materials are formed.

*Crumpled paper:


When you crumpled a paper, the form and size must also change to the original that you get.






Now we are going to go with the Chemical changes.
Chemical changes is one that involve a chemical reaction. New materials are formed in chemical changes. The color,odour, shape or structure is also change. The new materials formed cannot be changed back into the original formed. I have some examples that shows chemical changes such as:


*Baking a cake:


When we bake a cake we always need the ingredients that we need, for example flour, eggs, milk and other. Then, we mix them all together and it will become a cake, means when we bake a cake, we need so many new materials to mix.


*Burning candles:


Candle is source of light and heat, if it's cold or black out. It consist of solid, black of fuel, which made of wax, and a wick. Like wood, wax is mainly made up of carbon.






*Reaction of vinegar with bicarbonate of soda:


Bicarbonate of soda is a white powder that is used in baking. Vinegar is a colorless and weak acid that is used as a flavouring in cooking.










So if you want to do/test if it's true or not, such as the experiment above, you can try!

Human Population

The main cause of human population changes is the change in birth rate and death rate. The human population growth is caused by a natural increase that occurs when the number of births in the population exceeds the number of deaths in the population. 

There are some factors that effecting the human population: 

• Birth rate is the number of live babies born in a year for every 1000 people. A high birth rate may be caused by:

                         
     

- early marriages.     - lack of knowledge of birth control.

• Death rate is the number if people dying in a year for every 1000 people. A high death rate may be caused by:

        

- Diseases               - famine        - natural disasters 

Life expectancy becomes higher and death rate decreases.

Decreases in population size           

                                    

                                         

A low birth rate together with an ageing population may on the other hand result in a decrease in population size. A population is considered ageing when:

• people under the age of 15 make up less than 30% of the population .
• people above the age of 65 make up more than 6% of the population.

The human population may be describe by its population density. Population density refers to the number of people in given amount of space. Population density is an average value. One of the factor that affects the population density of a place is migration.

Human migration is human movement from one area to another. People who migrate are called migrants. Human migration may occur in the form of immigration or emigration.

Immigration takes place when people move into a country permanently. People who immigrate are called immigrants. A population growth may occur in an area when the amount emigration.

Emigration takes place when people move out of the country permanently. People who emigrate are called emigrants. The population density of a country can decrease as a result of emigration.

The picture on the right side is showing an area that have a low population density.

Area that have low population means that it is the healthy place..

The picture on the left side is showing a  place that have too much population density. That place is not healthy and it is not  a good place to live in.

FROM THIS ARTICLE WE CAN START LIVING HEALTH IS GOOD FROM NOW SO THAT WE CAN MAKE ALL THE WORLD IS FREE FROM ANY POLLUTION !! 

Pollution

Air pollution occurs when harmful substances or pollutants are released into the air.

The causes of air pollution is :

• Burning of fuels, rubbish and forests                      
• Dust and dirt in the air 
• Smoke from cigarettes                                       

The effects of air pollution are :

• Health problems 
• Haze 
• Acid rain                                                                                   

Water pollution occurs when pollutants are released into the water. These pollutants include:

* Harmful chemicals from factories and farms.

* Rubbish                                                                                      

* Human waste 

*Oil spills

The effects of water pollution are:\

* Harms organisms in water

* Harms people

Soil pollution occurs when pollutants are released into the soil. These pollutants include:

- Rubbish

- Harmful chemicals from farms

The effects of soil pollution are :

-Air pollution                                                                         

- Water pollution

- Deterioration of soil condition

-Growth of germs and pests

Picture on the side that is one example of images showing that it is a picture of eachstate of pollution contained in the above. If you wanna save the world you can read the picture that I put down.