Grade 3 NSO papers
A look at the previous lessons on earth and universe :
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
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).
- The sensory nerves and sense organs of the peripheral nervous system (PNS) monitor conditions inside and outside of the body and send this information to the CNS
The endocrine system is made up of the pituitary gland, thyroid gland, parathyroid glands, adrenal glands, pancreas, ovaries (in females) and testicles (in males)
The reproductive system is a collection of internal and external organs — in both males and females . It helps to produce young ones. Due to its vital role in the survival of the species, many scientists argue that the reproductive system is among the most important systems in the entire body.
Important words in human body
Building block of our body. Your body is made up of trillions of tiny cells, which are the basic units of life–the smallest building blocks of a living thing.
A tissue is a group of similar cells that all work together on the same job.
Organs are collections of tissues with similar functions. In higher animals, organs are grouped into organsystems; e.g., the esophagus, stomach, and liver are organs of the digestive system.
Blood vessels :
Thin tubes through which blood flows.
Arteries, which usually look red, are blood vessels that carry blood away from the heart to all the parts of your body They have very thick walls which allow them to withstand the immense pressure created as your heart pumps blood forcefully. As blood travels outward, the arteries become smaller and smaller until eventually the blood enters into what are known as capillaries.
Capillaries are so tiny that blood usually can only get through one cell at a time. It is within the capillaries that oxygen is taken in by the cells, and waste, such as carbon dioxide, is released into the blood.Eventually the capillaries get bigger and bigger, and then the blood enters into veins. As the blood travels back to the heart your veins get larger and larger.
Veins, which usually look blue, are blood vessels that return blood to the heart.
Strong tissue that joins muscles to the bones.
Fibre-like structures in the body that transmits messages to the brain.
Part of the digestive system that secretes juices that digest fats and protein.
Part of the digestive system that secrete bile, which helps absorb fats.
Gall bladder :
Part of the digestive system that stores extra bile.
Part of the respiratory system, pharynx, or throat, is part of the passage (or tube!) that air will go down to enter our lungs.
Part of the respiratory system ,the voice box, another part of our main air passage.
The windpipe is a long tube that goes down our neck to the lungs. There is also cilia in the windpipe. The windpipe’s lining makes mucus, which traps dust and other dirt particles. Cilia brings this mucus towards our throat, where we swallow and digest it.
Bronchi and Bronchioles
Tubes that branch from the trachea into our lungs. The bronchioles make a tree-like structure in the lungs so air can reach every corner.
Two spongy organs in our chest. Lungs have a lot of little air sacs called alveoli. Tiny blood capillaries run through alveoli. When air reaches the alveoli, it passes into the bloodstream. It is then carried around our entire bodies.
The main muscle in the respiratory system. The diaphragm stretches out underneath the lungs. When it contracts, it expands outwards. This makes more space inside our chest for air to rush in. When the diaphragm relaxes, it moves inwards. This decreases the space inside our chest and pushes air out.
We have already covered Skeletal, immune, cardiovascular, muscular and integumentary system in 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.
A look at the grade 2 lessons
Our body is made up of different organs and organ systems. There are in all 12 systems in our body
The integumentary system consists of the skin, hair, nails, glands, and nerves. It’s main function is to act as a barrier to protect the body from the outside world. It also functions to retain body fluids, protect against disease, eliminate waste products, and regulate body temperature.
The adult human skeletal system consists of 206 bones, as well as a network of tendons, ligaments and cartilage that connects them. The skeletal system performs vital functions — support, movement, protection, blood cell production, calcium storage and endocrine regulation — that enable us to survive.
- It stores calcium in our body.
- Gives shape to our body
- Protects vital organs like heart, brain, lungs etc
- The skull protects our brain
- Ribcage protects the heart, lungs, liver etc
- The backbone protects the spinal cord.
- Produces red blood cells
Muscular system is the system of Human Body that provides motor power for all movements of body parts. Muscular system is composed of special tissue called muscular tissue. Muscles have the ability to contract actively to provide the force for movements of body parts.–
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
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
Healthy and fast as it does not require any oil
Softens food which makes it easier to chew.
Water soluble vitamins are lost.
Cooks food in dry heat in an enclosed space like a convection oven.
The dry heat involved in the baking process makes the outside of the food go brown, and keeps the moisture locked in.
Example: Pastries, bread , cake etc
Food cooked by baking is soft and easy to digest
Cooked with a set timer so does not require constant attention
Takes time to cook food sometimes in hours.
Food is submerged in hot oil which gives it a crisp texture
Example : french fries, chips etc
Frying foods is quick and faster than preparing to cook a meal.
It is tasty .
Oil, which is what fried foods are cooked with, is full of fat which is high in calories and bad for the body
Nutritional value of fried food is poor.
Heating vegetable oil above 300oc damages the oil thereby causing toxin formation in the food.
Fried foods clog arteries and most times lead to stroke.
It is a method that uses dry heat to cook the food item. Roasting is best used for larger pieces of meat or some types of vegetables
Many vitamins stay in the food rather than being cooked away
Requires less oil than frying.
It takes a while for meat to roast thoroughly.
Uses dry heat from a gas , glowing charcoal or electric grill . This is similar to barbeque.
Example : Tikkas , grilled mushroom , grilled vegetables etc
Fast way of cooking
Requires less oil than frying.
Surface of the food can easily get burnt if enough oil is not brushed.
Food is cooked by the water vapor or the steam produced by boiling water.
Example : Steamed vegetables, momos , Idli etc
Softens food which makes it easier to chew.
Requires little or no oil
A quick look at the Grade 1 lessons :
- 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
Bird, a warm-blooded vertebrate that lays eggs and has feathers and wings.
Type of beaks