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UNIT 12 HUMAN POPULATION

UNIT 12 HUMAN POPULATION 12.1 HUMAN POPULATION The number of population is increase over the time. The main cause of population changes is the change in birth rate and death rate . A high birth rate may be caused by early marriages and lack of knowledge of birth control. A high death rate may be caused by diseases, famine, and natural disasters.   A high birth rate and a low death rate will result in increase in the size of population.  A low birth rate and a high death rate will result in decrease in the size of population. Life expectancy may become higher with the improvement in health care and hygiene 12.2 POPULATION DENSITY Population density refers to the number of people in a given amount of space. When the population grow, the population density will increase. Population density is affected by human migration . Human migration is movement from one area to another. Human migration may occur in the form of immigration and emigratio...

Science 4 UNIT 10 WEATHER AND CLIMATE

UNIT 10 WEATHER AND CLIMATE 10.1 Measuring air temperature The weather report usually shows the minimum and maximum temperatures for each day. The temperature of the air around us is measured using a room thermometer. 10.2 Humidity Humidity or relative humidity is a measure of the amount of water vapor in the air. Water vapor is water in its gaseous state. A hygrometer measures how humid or dry the air is. 10.3 Atmospheric pressure We know the present of the air because of wind and atmospheric pressure . Atmospheric pressure is the force of air pushing an area. 10.4 understanding the features of weather There are many factors that affect weather of a region. These factors are air temperature, wind speed, and direction, clouds and rainfall. Air temperature is usually higher during the day than during the night. Air temperatures change due to cloud cover and presence of rain . Air moves from an area with high pressure to an area with low pressure. ...

Science 4 Unit 12 mixing materials

Unit 12 mixing materials 12.1 mixing materials Different materials have different properties. Three states of materials: solid, liquid, gas a. Mixing a solid and liquid materials No Mixture Result Character 1 Pebbles + water Does not mix Doesn’t dissolve, insoluble 2 Sugar + water Mix completely Dissolves, soluble, solution 3 Chalk + water Mix not completely Dissolve, soluble, not solution. b. Mixing liquid and liquid materials No Mixture Result Character 1 Oil + water Does not mix Immiscible liquids 2 Fizzy drink + water Mix completely Miscible liquid 12.2 solubility of materials Solubility : the greatest amount of material that can dissolve in a certain amount of liquid at a particu...

Science 4 Unit 11 materials

Unit 11 materials 11.1 properties of materials Material are used to make objects. Properties are the characteristics of materials. Materials properties include hardness, flexibility, ductile, buoyancy, strength, and resistance. Hardness: the material ability to withstand wear and scratches. a.      Hard material Materials:   diamond, glass, ceramic, aluminum Object: glass cutter, window pane, tea pot, drink can b.     Soft material Materials: rubber, fabric Object: erases, cloth   Flexibility: the material ability to bend without breaking. a.      Flexible material Materials: plastic, rubber, Object: plastic ruler, water hose b.     Rigid material Materials: glass, Object: plate   Ductile: the material ability to be pulled into wire a.      Ductile material Materials: copper, gold, iron, aluminum Object: coper wire b.     Non-ductile ma...

UNIT 11 POLUTION

UNIT 11 POLUTION AIR POLLUTION air pollution occur when harmful substances or pollutant are released to the air. Causes of air pollution are : burning of fuels, rubbish, and forests. Dust and dirt in the air smoke and cigarettes the effect of air pollution are: health problem haze acid rain WATER POLLUTION water pollution occur when harmful substances or pollutant are released to the water. Causes of water pollution are : harmful chemical from factories and farms rubbish human waste oil spills the effect of water pollution are: harms organism in water harms people SOIL POLUTION soil pollution occur when harmful substances or pollutant are released to the soil. Causes of air pollution are : rubbish harmful chemical from farms the effect of soil pollution are: air pollution water polution deterioration of soil condition growth of germs and pest. ...

UNIT 10 ADAPTATIONS OF LIVING THINGS TO THE ENVIRONMENT

UNIT 10 ADAPTATIONS OF LIVING THINGS TO THE ENVIRONMENT 1.1       LIVING THING AND THEIR HABITAT Adaptation is living things special characteristics that help them to survive in their natural habitats. Living thing adaptation can be structural or behavioral. Structural adaptations are parts of living thing’s body that help them to survive in its’ natural habitat. Example animal’s shape, colors, and body covering. Behavioral adaptations are special ways in which living things act and behave to survive in its natural habitat. Example birds call, migration, and hibernation. Habitats include places such as forests, lakes, rivers, seas, desserts, and even extremely cold regions like arctic and Antarctic. Adapted living things are able to: ·          Get air, water, and food. ·          Cope with the physical conditions. ·      ...