Wednesday, June 5, 2013

Air and Water Science

Air and water are two essential things on earth without which life would not possible:
Air
Air is the natural mixture of gases that surround the earth. It is made of 79% nitrogen, 20% oxygen, and 1% other gases, mostly carbon dioxide, and a bunch of others gases. The composition of air changes depending on the place. For example, at very high altitudes, there is a lot of ozone, that reduces the amount of ultraviolet light that comes from the sun and gives us cancer and sunburns.
Air is used to burn things, for example, a log. The oxygen in the air reacts with the stuff in the log to make a bunch of new stuff.
The air we breathe in is used to burn the stuff we eat to make energy. The oxygen in the air drives our life. Plants use the carbon dioxide in the air to make sugars which they will later burn for energy.
Air also suspends clouds, which are water and turn into rain. This means that water moves in the form of a cycle. If water just sat around, a lot of things could only grow in a river. Air also suspends objects that float on air.
In conclusion, air keeps things alive and powers the planet (and wastes your gas money, and kills people).
Know more about this click here Water Contamination and Water Contamination Facts
Water
Water is a chemical substance with the chemical formula H2O. Its molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state, water vapor or steam.

Water covers 71% of the Earth's surface, and is vital for all known forms of life. On Earth, it is found mostly in oceans and other large water bodies, with 1.6% of water below ground in aquifers and 0.001% in the air as vapor, clouds (formed of solid and liquid water particles suspended in air), and precipitation. Oceans hold 97% of surface water, glaciers and polar ice caps 2.4%, and other land surface water such as rivers, lakes and ponds 0.6%. A very small amount of the Earth's water is contained within biological bodies and manufactured products.

Water moves continually through a cycle of evaporation or transpiration (evapo transpiration), precipitation, and runoff, usually reaching the sea. Over land, evaporation and transpiration contribute to the precipitation over land.

Clean drinking water is essential to human and other life forms. Access to safe drinking water has improved steadily and substantially over the last decades in almost every part of the world.
 The groundwater and fresh water are useful or potentially useful to humans as water resources.


Water is fundamental to photosynthesis and respiration. Photosynthetic cells use the sun's energy to split off water's hydrogen from oxygen. Hydrogen is combined with CO2 (absorbed from air or water) to form glucose and release oxygen. All living cells use such fuels and oxidize the hydrogen and carbon to capture the sun's energy and reform water and CO2 in the process (cellular respiration).

Both air and water exerts pressure in all directions.

Wednesday, May 29, 2013

Science Questions for 5th Graders

Introduction to science questions for  5th grade:

The word Science is formed from the Latin word 'Scientia' which means "knowledge". Thus science is an enterprise of gathering knowledge and then organizing that knowledge into laws and theories. Literacy in Science is the ability of the people to understand the basic concepts related to science.

Science can be classified into 3 main parts - Physics, Chemistry, Biology.


Plant tissue

Some science questions for 5th graders:



The science questions and answers for 5th graders are as follows:

1. In what ways are plants useful to us?

Answer: Plants provide us with food, oxygen, building materials, fibres for clothing, medicines and many other things.

2. What is migration ?

Answer: Migration is the periodic movement of animals from one place to another and back to their original homes. Migration takes place in search of food or because of climatic changes.

3. Write down the names of the three main classes of rocks.

Answer: According to the method of their formation, rocks are divided into three classes:

a) Sedimentary

b) Igneous

c) Metamorphic

4. Name the gases that are found in the air.

Ans: The gases present in the air are:

1. Nitrogen                      2. Oxygen

3. Carbon dioxide           4. Water Vapour

5. Name the first man who landed on moon.

Ans: The first man who landed on moon was Neil Armstrong. He landed on moon on the 20th of July, 1969.


More science questions for 5th Graders:


6. What is the nervous system made up of?

Answer: The entire nervous system is made up of special cells called the nerve cells or neurons and nerve fibres. The human nervous system can be divided into three parts:

(1) The central nervous system which consists of the brain and the spinal cord.

(2) The peripheral nervous system consisting of the nerves arising from the brain and the spinal cord.

(3) The automatic nervous system which is made up of special collections of nerve cells (ganglia) and nerves control the working of the internal organs. This system is not under the control of our will.

7. Write the definition of the term pollution.

Answer: Pollution is the addition of any material or forms of energy in air, water or land which adversely alters the natural quality of the environment.

8. Name the six main types of simple machines.

Answer: The simple machines can be grouped into six types:

(1) the lever                      (2) the wheel and axle

(3) the pulley                    (4) the inclined plane

(5) the screw                    (6) the wedge

9. Name the three states of matter.

Answer: Matter is found in three states - solid, liquid and gaseous.

10. What are communicable and non-communicable diseases?

Ans: Communicable: Communicable diseases are those diseases which are passed on from one person to another.

E.g. Diseases caused by micro organisms like typhoid, cholera, measles, chickenpox, malaria, amoebic dysentery, ringworm.

Non-communicable: Non-communicable diseases are not passed on from one person to another.

e.g Disorder of body organs (Diabetes), cancer, mental illness, deficiency diseases (anaemia, goitre, scurvy), diseases due to old age etc.

If you want to know more clarification click here Alpha Helix and Green Chemistry