Science and Technology, Part 2
The last GK chapter! Your body's hidden names, five systems of medicine, seven gemstones, fourteen space "firsts," and the seven basic units of measurement.
3.5 Body Knowledge
| Clue | Answer |
|---|---|
| The voice-box | larynx |
| The master gland | pituitary |
| The sweetbread | pancreas |
| The controllers of chemical reactions | enzymes |
| The vein that carries oxygenated blood | pulmonary vein |
| The contractile structure surrounding the pupil | iris |
| The white area of the eye | sclera |
| The air sacs in the lungs | alveoli |
| Lets light enter the retina | pupil |
| The shock absorber in the body | cartilage |
| Organ considered as blood reservoir | spleen |
| Another name for milk teeth | deciduous |
| The longest bone | femur |
| The strongest muscle | masseter |
| The largest internal organ | liver |
Every other vein carries deoxygenated (used-up) blood back to the heart. The pulmonary vein is the ONE exception — it carries oxygenated blood, from the lungs to the heart.
The eye (3): iris, sclera, pupil. Bones/support (3): cartilage, femur, masseter. Blood (2): pulmonary vein, spleen. Glands/chemistry (3): pituitary, pancreas, enzymes. Breathing (2): larynx, alveoli. Odd ones (2): deciduous, liver. Pituitary = "master gland" because it controls many other glands — remember it as the body's "boss."
The pupil of the eye is transparent, but appears black because most light entering it is absorbed by tissues inside the eye.
3.6 Alternative Forms of Medicine
Five systems of medicine from around the world, other than the "modern medicine" you see at a hospital.
| System | Key facts |
|---|---|
| Ayurveda | Oldest surviving complete medical system in the world. "Ayur"=life, "ved"=knowledge. Health = balance of air, earth, fire, water. Treats illness at its source. |
| Unani | Originated in Greece (Galen's principles), enriched by Arab philosopher Abu Shina, introduced to India ~10th century AD. Disease is a natural process; symptoms are the body's reaction. |
| Reiki | Japanese method — hands placed on the body to channel cosmic/universal energy for healing. Founded by Mikao Usui. |
| Naturopathy | Believes in nature's healing power. Started and popularised in the US by German doctor Benedict Lust, in 1905. |
| Acupuncture | Ancient Chinese treatment. The body has 12 organ channels and 365 points; needles stimulate these points. (Acupressure is similar but uses hands, not needles.) |
Both use the same 12 channels and 365 points. Acupuncture uses needles. Acupressure uses hands (pressure, no needles). Same idea, different tool.
Ayurveda → India. Unani → Greece, spread through the Arab world, reached India in the 10th century. Reiki → Japan (founder Mikao Usui). Naturopathy → popularised in the US (by a German doctor). Acupuncture → China.
3.7 Precious Stones
Gems are mostly coloured stones cut into shapes and polished for jewellery — gems from minerals are perfect single crystals. Seven gemstones with their composition and colour.
| Stone | Made of | Colour |
|---|---|---|
| Ruby | Transparent red corundum (aluminium oxide) | Deep cochineal to pale rose-red, sometimes purple-tinged |
| Diamond | Pure carbon | Hardest naturally occurring substance; usually colourless |
| Amber | Fossilised tree resin (extinct conifer/pine trees), millions of years old | May trap insects and air bubbles |
| Topaz | An aluminium silicate mineral | Usually colourless or pale yellow to wine-yellow; pale blue/green too |
| Cornelian | A variety of the silica mineral chalcedony | Reddish-brown, pale orange to almost-black |
| Sapphire | A variety of corundum (same mineral as ruby!) | Pale blue to deep indigo (colour from iron and titanium) |
| Emerald | Green beryl (beryllium aluminium silicate) | Grass-green, coloured by chromium and vanadium |
Both are made of corundum — red corundum is called ruby, blue (or other-coloured) corundum is called sapphire. Same mineral, two gem names. Silicate minerals (3): Topaz, Emerald, Cornelian. Pure element (1): Diamond — just carbon. Not a mineral at all (1): Amber — it's fossilised tree resin, an organic substance.
The world's largest diamond was the Cullinan, found in South Africa in 1905. It weighed 3,106.75 carats uncut, and was cut into the Great Star of Africa (530.2 carats), the Lesser Star of Africa (317.4 carats), and 104 other diamonds — now part of the British crown jewels.
3.8 Space Achievers
A satellite revolves around a planet in a circular or elliptical path — natural (like the Moon) or man-made. Fourteen space "firsts" — the longest space list yet.
| First… | Answer |
|---|---|
| Artificial satellite launched into space | Sputnik I |
| Spacecraft to land on another planet | Venera-3 (Venus) |
| Spacecraft to orbit Saturn | Cassini-Huygens |
| Navigational satellite system | Transit |
| Satellite to carry Laika (a dog) into space | Sputnik II |
| Communication satellite put into space | Score |
| Satellite to carry a man into space | Vostok (Yuri Gagarin) |
| Artificial Indian satellite | Aryabhata |
| Commercial communications satellite | Early Bird |
| Satellite providing transatlantic television | Telstar-1 |
| Spacecraft to hit the moon | Luna-2 |
| Privately funded human spaceflight | SpaceShipOne |
| Stationary Earth satellite (geostationary) | Syncom-3 |
| Second artificial Indian satellite | Bhaskara |
Soviet/Russian (4): Sputnik I, Sputnik II (Laika), Vostok (Gagarin), Venera-3. Indian (2): Aryabhata (1st), Bhaskara (2nd) — learn as a pair. Communication (3): Score (first), Early Bird (first commercial), Telstar-1 (first transatlantic TV). Reaching other worlds (3): Luna-2 (Moon), Venera-3 (Venus), Cassini-Huygens (Saturn) — further and further out. Modern/private (1): SpaceShipOne (2004, much more recent).
The first animals intentionally sent into space were fruit flies, along with corn seeds, aboard a USA-launched V2 rocket in 1947.
3.9 Measurements
Measurement identifies seven basic units from which all other units are derived.
| Basic unit | Measures |
|---|---|
| Metre (m) | Length |
| Kilogram (kg) | Weight |
| Second (s) | Time |
| Candela (cd) | Luminous intensity |
| Ampere (A) | Electric current |
| Kelvin (K) | Temperature |
| Mole (mol) | Amount of substance |
Length: 1 inch = 25 mm; 1 foot = 0.3 m; 1 yard = 0.9 m; 1 mile = 1.6 km. Weight: 1 ounce = 28 g; 1 pound = 0.45 kg. Area: 1 square inch = 6.5 cm²; 1 square foot = 0.09 m²; 1 square yard = 0.8 m²; 1 acre = 0.4 hectare. Volume: 1 cubic inch = 16 cm³; 1 cubic foot = 0.03 m³; 1 cubic yard = 0.8 m³.
| Volume equivalent | Area equivalent |
|---|---|
| 1 cubic inch = 16 cubic centimetres | 1 square inch = 6.5 square centimetres |
| 1 cubic foot = 0.03 cubic metre | 1 square foot = 0.09 square metre |
| 1 cubic yard = 0.8 cubic metre | 1 square yard = 0.8 square metre |
| 1 acre = 0.4 hectare |
Fahrenheit (F) = (C × 1.8) + 32. Celsius (C) = (F − 32) / 1.8. Remember −40° from Section 3.4 — that's the one point where these two formulas give the exact same number on both scales!
The "Equivalents" above are handy rounded numbers. But the book also gives exact Conversion formulas — precise multipliers to use when you need an accurate answer, not just a rounded estimate.
| To convert… | Multiply by |
|---|---|
| Ounces → grams | grams = ounces × 28.3495 |
| Pounds → kilograms | kilograms = pounds × 0.453592 |
| Celsius → Fahrenheit | F = (C × 1.8) + 32 |
| Fahrenheit → Celsius | C = (F − 32) / 1.8 |
| Sq. inches → sq. centimetres | cm² = sq inches × 6.4516 |
| Sq. feet → sq. metres | m² = sq feet × 0.092903 |
| Acres → hectares | hectares = acres × 0.404686 |
| Inches → centimetres | cm = inches × 2.54 |
| Centimetres → inches | inches = cm × 0.3937 |
| Feet → metres | m = feet × 0.3048 |
| Miles → kilometres | km = miles × 1.60934 |
| Kilometres → miles | miles = km × 0.621371 |
The Equivalents table gives quick, rounded facts (like "1 foot = 0.3 m") for remembering. The Conversions block gives the exact multiplier to use in a calculation (like "metres = feet × 0.3048"). Notice inches→cm (×2.54) and cm→inches (×0.3937) go in opposite directions — don't mix them up!
Try it: 10 pounds in kilograms = 10 × 0.453592 = 4.53592 kg — matches the rounded equivalent (1 pound ≈ 0.45 kg, so 10 pounds ≈ 4.5 kg). Same idea, just more decimal places!
Practice like the real exam
Pulmonary vein
False — acupuncture uses needles; acupressure uses hands.
(b) corundum
Aryabhata (1st); Bhaskara (2nd)
Candela (cd)
Cullinan; South Africa; 1905
0.8 cubic metre; 0.8 square metre — both yard equivalents are 0.8!
20 × 0.453592 = 9.07184 kg
km = miles × 1.60934; miles = km × 0.621371
You did it — all of GK complete! 🎉
🏁 GK Chapter 4 · Sections 3.5–3.9 · Prishita, Class 8