PPSC Educators Test Everyday Science Syllabus

Differentiate between a physical change and a chemical change.

A physical change alters form/state but not composition and is usually reversible (e.g., melting ice); a chemical change forms a new substance and is usually irreversible (e.g., burning wood).

What is the pH scale, and what do acids and bases register?

The pH scale ranges from 0 to 14; acids have pH below 7, bases (alkalis) have pH above 7, and pure water (neutral) has pH 7.

What do acids and bases turn litmus paper?

Acids turn blue litmus red; bases (alkalis) turn red litmus blue.

What is a neutralization reaction?

The reaction between an acid and a base that produces a salt and water (Acid + Base → Salt + Water).

What are the common names of NaCl, NaHCO₃, and CaCO₃?

NaCl is common/table salt; NaHCO₃ is baking soda (sodium bicarbonate); CaCO₃ is limestone/chalk/marble (calcium carbonate).

What is the chemical name and use of H₂SO₄?

H₂SO₄ is sulphuric acid, known as the 'king of chemicals'; used in batteries, fertilizers, and industrial processing.

What is the function of the cell membrane and the nucleus?

The cell membrane controls the entry and exit of substances; the nucleus controls all cell activities and contains genetic material (DNA).

What is the basic difference between plant and animal cells?

Plant cells have a cell wall, chloroplasts, and a large central vacuole; animal cells lack a cell wall and chloroplasts and have small vacuoles.

Define tissue and organ.

A tissue is a group of similar cells performing a common function; an organ is a group of different tissues working together to perform a specific function.

Which organelle is called the 'powerhouse of the cell' and why?

The mitochondrion, because it produces energy (ATP) through cellular respiration.

What is the function of the human digestive system, and where is most absorption?

It breaks down food into absorbable nutrients; most absorption of nutrients occurs in the small intestine.

What is the main function of the respiratory system?

To take in oxygen and remove carbon dioxide; gas exchange occurs in the alveoli of the lungs.

How many chambers does the human heart have, and what are they?

Four chambers: two upper atria (right and left) and two lower ventricles (right and left).

What is the largest organ of the human body, and what is the largest internal organ?

The skin is the largest organ overall; the liver is the largest internal organ.

Name the deficiency diseases caused by lack of Vitamin C and Vitamin D.

Vitamin C deficiency causes scurvy; Vitamin D deficiency causes rickets (in children) and osteomalacia (in adults).

Which vitamin deficiency causes night blindness, and which causes beriberi?

Vitamin A deficiency causes night blindness; Vitamin B1 (thiamine) deficiency causes beriberi.

What are the main macronutrients in food and their primary roles?

Carbohydrates (energy), proteins (growth and repair), and fats (energy storage and insulation).

Which mineral deficiencies cause anaemia and goitre?

Iron deficiency causes anaemia; iodine deficiency causes goitre.

What are the main gases in Earth's atmosphere by percentage?

Nitrogen about 78%, oxygen about 21%, and argon, carbon dioxide, and other gases about 1%.

What is the role of the ozone layer, and which gases deplete it?

The ozone layer (in the stratosphere) absorbs harmful ultraviolet (UV) radiation; it is depleted mainly by chlorofluorocarbons (CFCs).

Name the main greenhouse gases responsible for global warming.

Carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O), water vapour, and CFCs.

Differentiate between renewable and non-renewable natural resources.

Renewable resources can be replenished naturally (e.g., solar, wind, water, forests); non-renewable resources are finite and deplete with use (e.g., coal, oil, natural gas).

What is an ecosystem, and what is a food chain?

An ecosystem is a community of living organisms interacting with their non-living environment; a food chain is the sequence of who eats whom, showing energy transfer (producers → consumers → decomposers).

What does LASER stand for?

Light Amplification by Stimulated Emission of Radiation.

What technologies do GPS and RADAR use?

GPS (Global Positioning System) uses satellites to determine location; RADAR (Radio Detection and Ranging) uses radio waves to detect the position and speed of objects.

List the planets of the solar system in order from the Sun.

Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.

Which is the largest planet and which is the closest to the Sun?

Jupiter is the largest planet; Mercury is the closest planet to the Sun.

What causes day and night, and what causes the seasons?

Day and night are caused by Earth's rotation on its axis (24 hours); seasons are caused by Earth's revolution around the Sun combined with the tilt of its axis.

Name the layers of the Earth's interior from outside to inside.

Crust, mantle, outer core (liquid), and inner core (solid).

What instrument measures earthquakes and atmospheric pressure?

A seismograph measures the intensity of earthquakes; a barometer measures atmospheric pressure.