A look at the previous lessons on earth and universe :
Grade 2 Science (NSO) : Earth and universe
Weather and The Sky: Earth and Sky fundamentals
The motion around the sun along its orbit is called a revolution . The amount of time it takes for a single trip around the sun is called a period of revolution. The period for the Earth to revolve around the sun is 365.24 days or one year. The .24 days is why every four years February has 29 days.
There are 4 seasons in an year .In Autumn and Spring the northern and southern hemispheres are tilted equally toward the sun.In Summer the Earth is on the other side of the sun and the northern hemisphere is tilted toward the sun and gets better sun rays. In winter the northern hemisphere is tilted away from the sun. That’s how we get seasons.
Earth’s orbit around the sun is slightly elliptical, Earth is actually slightly closer to the sun in the winter than it is in the summer.It is the tilt of Earth’s axis that causes the seasons.
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).
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.
Before starting lets take a look at the Grade 2 lessons
Plant – Types of plants
Plants – Parts we eat
Plants : Uses of different plants
Responsible for reproduction
Colour and fragarence of flowers attract insects who act as pollinators.
Flower parts that we eat :