Science for Kids Again Trivia Quiz

Answer: Limewater

Acids are compounds which release hydrogen ions when dissolved in water. Alkalis are bases that are soluble in water and release hydroxide ions in water. Limewater contains calcium hydroxide, obtained by the slaking of quicklime. Vinegar contains acetic acid. Tomato juice contains oxalic acid. Lemon juice contains citric acid and ascorbic acid (vitamin C). Limewater can be used over fresh plaster to polish it.

Answer: Velocity

If the velocity of a body changes from 'u' to 'v' in time 't', its average acceleration during that time is (v-u)/t. The mass of a body multiplied by its velocity gives the momentum of the body. By Newton's laws, the rate of change of momentum is the external force applied on the body. This gives us the relation Force = Mass x Acceleration.

Answer: Vitamin D

Vitamin D is a group of vitamins soluble in fat. It is required for the proper absorption of minerals such as calcium and magnesium into the blood from the small intestine. Its synthesis is triggered by the ultraviolet rays of the sun. Deficiency of vitamin D can cause rickets in children, which leads to weak, deformed and soft bones.

The most common compounds belonging to this group are ergocalciferol and cholecalciferol.

Answer: Kite

A kite has one line of symmetry, but does not possess a centre of rotational symmetry. A kite with all four sides equal is a rhombus. If a kite is also a cyclic quadrilateral and can be inscribed in a circle, the angles made by the unequal sides must be right angles.

The diagonal connecting the other two vertices is the diameter of the circumscribing circle. A parallelogram is a quadrilateral with opposite sides parallel and equal in length. A rhombus is a parallelogram with all four sides equal.

A trapezium refers to any quadrilateral with two opposite sides parallel.

Answer: Skin

Earthworms belong to the Phylum Annelida. Their body is divided into many segments. They have a closed circulatory system. Earthworms are beneficial for the soil, as they decompose organic matter into nutrients essential for plants to grow. They do not have specialised organs for breathing. Air is taken in through the skin and oxygen is transported through the plasma.

Answer: Five

A prism consists of two faces of the same dimensions, connected by rectangular faces. Thus, a triangular prism has two triangular faces, and three rectangular faces, five faces in all. If the number of edges, faces, and vertices in a three-dimensional object be E, F and V, we have a relationship E+2=F+V.

A triangular prism has nine edges and six vertices. A rectangular prism is simply a cuboid.

Answer: Radiation

There are three modes of heat transfer - conduction, convection and radiation. Conduction involves heat of transfer when two bodies are in direct contact with each other. The flow of heat occurs without the movement of the molecules in the bodies. It mostly happens in solids. Convection involves flow of heat that occurs due to the movement of molecules in fluids.

It occurs in liquids and gases. Radiation involves transfer of heat as an electromagnetic wave. It can even occur through a vacuum. Heat from the sun reaches the earth through radiation. Refraction refers to bending of light at an interface between two media.

Answer: Fluorine

When an atom is bonded with another atom, the electronegativity of an atom is defined as the tendency to pull the bonded pair of electrons towards itself. In the periodic table, electronegativity usually decreases down a vertical group, as the force of attraction by the positively charged nucleus decreases with increasing distance. Electronegativity usually increases from left to right in a period, due to smaller atomic size, and increasing effective nuclear charge and force of attraction. Fluorine is the most electronegative element.

It is in Group 17, and is a halogen. Fluorine is more electronegative than oxygen, which is in turn more electronegative than nitrogen, which is more electronegative than carbon.

Answer: Current

Electric current is defined as the charge flowing per unit time. It is measured in amperes. A voltmeter measures the voltage, or potential difference across two points. If the resistance of an electric component is R, and the direct current flowing through it is I, the potential difference across it is given by V = I x R. This is called Ohm's Law. Resistance is measured in ohms.

Answer: Kidneys

The metabolic processes in our body generate a lot of waste, which is excreted through sweat or urine. In human urine, the major waste product is urea, which is obtained when proteins break down. The major waste product in birds is uric acid. Failure of the kidneys to filter out the waste can even lead to death, unless some artificial procedure like dialysis is used.