What is soil
Soil is formed by erosion that is breaking up of rocks , by the action of sun, wind and rain. It forms at the surface of land and is the “skin of the earth.” Soil is capable of supporting plant life and is vital to life on earth.
Soil contains a lot of different things; a few essential ingredients are listed below:
Sediment – Every soil contains some mixture of sediments. The three main sediments are sand, silt, and clay. The type of sediments determines a soil’s type. Ideal soils (for farming) are a mixture of the three.
Organic Matter – Soil contains a lot of partially decomposed organisms which is called organic matter. Microbes in the soil break it down to make important nutrients. Most organic matter comes from plants. This is also called Humus and is dark brown or black in color.
Minerals – There are tons of different minerals in the soil. They’re used by plants for growth. When plants die, their minerals return to the Earth.
Types of soil and properties
Links to part 1 and part 2 of the human body
Grade 3 Science (NSO) : Human body part 1
Grade 3 Science(NSO) : Human body part 2
This system controls all our actions, sense of feelings and thinking is called Nervous system.The nervous system is a complex collection of nerves and specialized cells known as neurons that transmit signals between different parts of the body. It is essentially the body’s electrical wiring.
- It consists of the brain, spinal cord, sensory organs, and all of the nerves that connect these organs with the rest of the body
- Brain is the most vital organ of our body
- It sends and receives messages to and from all parts of the body through nerves
- Spinal chord is the bundle of nerves that runs up and down the center of the back; connects the brain to the nerves; carries signals between the brain and other parts of the body
- The brain and spinal cord form the control center known as the central nervous system (CNS).
We have already covered Skeletal, immune, cardiovascular, muscular and integumentary system in part 1.
Grade 3 Science (NSO) : Human body part 1
Lymphatic system :
It is responsible for the removal of interstitial fluid from tissues. It absorbs and transports fatty acids and fats as chyle from the digestive system. It transports white blood cells to and from the lymph nodes into the bones.
-picks up fluids leaked from the capillaries
-supports immune systems: houses white blood cells Continue reading
A look at the grade 2 lessons
Grade 2 Science (NSO): Human Body
Human beings: Parts of the body
Human beings : Sense organs
Our body is made up of different organs and organ systems. There are in all 12 systems in our body
Food Decay and Preservation
Bacteria and fungi are the main groups of decomposer organisms. Food decay is also known as food spoilage.
Bacteria and fungi need Food , Warmth and Moisture to grow.
There are several ways to stop or slow down the decay of foods. This is known as Food Preservation.
Food preservation methods
Bacteria cannot reproduce at low temperatures.
Bacteria and fungi need warmth to grow. In low temperatures they stop growing.
Following is the list of food preserved by freezing;
- Fresh foods
- Cooked foods
Removing water prevents the microorganisms from growing, or digesting the food.
A look at the grade 2 lesson
Grade 2 Science(NSO) : Food
Food can be divided into three types
Energy giving food
Give us energy to work. They contain carbohydrate and fats.
They are found in foods like rice, pasta, cassava, yam etc. when starchy foods are eaten and digested, simple sugars like glucose are obtained. It is this glucose that the body uses for energy.
There are two major types of carbohydrates:
1. Simple carbohydrates (Sugar)
- White sugar you would find in a sugar bowl
Cooking of food
Cooking improves the flavor of food and also makes the food easier to chew and more digestible. Micro oirganisms present in the food are killed during cooking which makes the food safer to consume. Various methods of cooking are listed below :
Involves cooking the food at the boiling temperature of water ie 100 degree centigrade.
Example : Eggs , potatoes etc
A quick look at the Grade 1 lessons :
Weather and The Sky:GK questions on space
Weather and The Sky: Earth and Sky fundamentals
- It is a star.
- It gives us heat and light
- It is the main source of energy on the earth
- Eight planets and many heavenly bodies revolve around the sun.
- Orbits the sun
- Has sufficient mass to be round, or nearly round
- Is not a satellite (moon) of another object