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.
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
Bird, a warm-blooded vertebrate that lays eggs and has feathers and wings.
Type of beaks
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 :