A Trip to a Science Fair Quiz | Sci / Tech

Quiz Answer Key and Fun Facts

1. Edward was first attracted to project no.23. That was an experiment on light. White light was entering the prism, but when the emergent light was received on a board, it formed a rainbow. Can you tell me what is that rainbow called?

Answer: Spectrum

The rainbow, or colour band is called spectrum. When white light is incident on (falls on) the first surface of a prism and enters in glass, light of different colours due to different speeds (wavelengths vary) in glass, is refracted (deviated) at different angles.

This deviation gets added up due to refraction at both surfaces of the prism and the colours get separated. Hence, the emergent light beam has all the colours of white light arranged in a definite order, and when that light is received on a screen, a spectrum is formed.

This phenomenon is called dispersion.

2. Edward then listened to a conversation between two boys. One was telling the other, "I am confident that sulphuric acid has a higher boiling point than hydrochloric or nitric acid". Was he correct?

Answer: Yes

That boy was correct. Hydrochloric acid forms a constant boiling mixture with water at 109.8 degree Celsius (22.2% concentrated), and its boiling point decreases with increase in concentration of acid. Pure nitric acid has a boiling point of 86 degree Celsius.

However, sulphuric acid has a boiling point of 338 degree Celsius and is considered a non-volatile, or least volatile acid. It can be used to displace both hydrochloric and nitric acid from their salts.

3. After travelling to the biology section, another interesting fact was registered in Edward's mind. Our mouth dries up, muscles become tense and heart beats faster if we are very nervous, but which emergency hormone is responsible for it?

Answer: Adrenaline

The hint was "emergency hormone." Adrenaline, or epinephrine, secreted from adrenal medulla is known as "emergency hormone" as it helps the body to deal with emergency situations like fasting, fight, overcooling or trauma. It breaks down glycogen and sends glucose to our bloodstream, thus providing us with extra energy whenever we need it and causes the heart to beat faster.

It also constricts the arterioles of digestive system, causing our mouth to dry up.

4. That was not the end of biological wonders. Edward learned that when we exercise very fast, an acid accumulates in our muscles which make us feel exhausted. What is the name of that acid?

Answer: Lactic acid

On exercising very fast, our muscles have to work very fast, but they do not get enough oxygen. Hence, they respire anaerobically (without oxygen) which produces a meagre amount of energy, two ATP, and lactic acid. The accumulated lactic acid makes us feel exhausted and cramps can occur due to it.

5. Another writing on a board caught Edward's attention. It stated that earthquake waves are of three types - primary waves, secondary waves and tertiary waves. However, another boy standing beside him correctly stated that "tertiary waves" is not a name given to a type of earthquake wave and gave the correct name of the third type of earthquake waves. What is that correct name?

Answer: Long waves

Long waves are slow waves which travel along Earth's surface. Their motion is either horizontal or vertical, much like sea waves. Primary waves of earthquakes can pass through gases, liquids and solids, while secondary waves can pass only through solids.

6. An experiment on flotation was being carried on. An iron ball was floating on mercury, while it sank in water. Why?

Answer: Mercury has a greater relative density than iron

Mercury does not react with iron. Archimedes proved that a body with relative density less than or equal to that of the fluid (liquids and gases) on which it is placed, will float while others would sink. Iron floats in mercury as it is much less denser than mercury (the density of iron is 7.8*10^3/metre^3 while the density of mercury is 13.6*10^3/metre^3).

7. Another fact was registered in Edward's mind while he was in the math section. We know that everything that exists has three dimensions (length, breadth and height), right? Which mathematical symbol did Edward see that lacked all three dimensions, yet still existed?

Answer: Point (dot)

A point does not have any dimensions. A cube is a three dimensional solid which has equal sides. A line lacks height and breadth, but possesses length. A circle can be defined by stating that the locus of all points equidistant from another fixed point, forms a circle. No other mathematical symbol other than the point lacks all three dimensions.

8. Edward always thought that crayoning was fun, but that night he learnt much more about colours. This question put forward by a boy particularly intrigued him: "Why do we use red light for danger signals, say, to stop a train when something is wrong"? What reason among the following contributes to red being an ideal colour for use in danger signals?

Answer: Red colour has the greatest wavelength, hence is scattered the least

Dust particles, water vapour and other particles present in atmosphere scatter light passing through the atmosphere. Scattering is directly proportional to (1/wavelength)^4 of incident light. As red light is scattered least due to its long wavelength, it can be seen from the longest distance and thus trouble can be averted.

9. Some acids were on display in a shelf. Beside each bottle, a descriptive card was kept. One read- "Aqua regia - only acid which dissolves gold and platinum". Do you agree?

Answer: Yes

Aqua regia is produced by combining three volumes of nitric acid with one volume of hydrochloric acid. It can dissolve noble metals like gold and platinum as it contains nascent chlorine [Cl], which is much more reactive than ordinary chlorine gas (Cl2).

The strong oxidising action of nitric acid also helps aqua regia to dissolve noble metals. Nitrosyl chloride and water are also formed during the production of aqua regia.

10. Edward was really amazed by all these stuff, but this experiment amazed him even more. A strong sugar solution was kept within a container made of a semi-permeable membrane (which allows liquid particles to pass) which was immersed in a beaker of distilled water. Before Edward's eyes, the level of solution in the container started to rise, while the water level in the beaker fell down. Which physiological process did this experiment demonstrate?

Answer: Osmosis

The process was osmosis. As the concentration of solution inside the container was high, water travelled from the beaker to the container to equalise the concentration. This process will continue till both solutions are of equal concentration. Diffusion is another process which follows the same procedure, though no semi-permeable membrane is present when diffusion occurs.

Source: Author remote9

This quiz was reviewed by FunTrivia editor WesleyCrusher before going online.
Any errors found in FunTrivia content are routinely corrected through our feedback system.

A Trip to a Science Fair Trivia Quiz

Edward was never a fan of science, but all that changed when he visited a science fair. Find out the ten interesting things that Edward saw by playing this quiz. Probably it will change your mind, too.

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