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Late-Night Science Exam Survival Kit

Targeted high-yield review for tomorrow's exam

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General

🔬 Scientific Learning

Scientific Method Steps:

  1. Observation & Questioning
  2. Hypothesis Formation
  3. Experimentation & Variable Control
  4. Data Collection & Analysis
  5. Conclusion & Reporting

Experimental Variables:

Independent: The variable you intentionally change/test.

Dependent: What you measure/observe (changes in response).

Controlled: Factors kept constant to ensure a fair test.

💡 Exam Tip: Formulate hypotheses strictly as "If [independent variable changes], then [dependent variable] will..."
Biology

🌿 Classification of Organisms

Whittaker's Five Kingdoms:

  • 1. Monera: Unicellular, Prokaryotic (no true nucleus). E.g., Bacteria.
  • 2. Protista: Unicellular, Eukaryotic. E.g., Amoeba, Paramecium.
  • 3. Fungi: Mostly multicellular, Saprophytic. E.g., Yeast, Mushroom.
  • 4. Plantae: Multicellular, Autotrophic (Cellulose wall).
  • 5. Animalia: Multicellular, Heterotrophic (No cell wall).

Binomial Nomenclature Rules:

Format: Genus species (e.g., Rana tigrina for Frog, Homo sapiens for Humans).

  • Genus starts with Capital letter; species with lowercase.
  • Italicized when printed; separately underlined when handwritten!
💡 Exam Tip: Prokaryote = No nuclear membrane (Monera only). All other 4 kingdoms are Eukaryotes.
Biology

🍄 Mushroom

Non-green, non-vascular saprophytic fungus growing on decaying organic matter.

Key Morphology:

  • Cap (Pileus): Umbrella-shaped top portion.
  • Gills (Lamellae): Radiating vertical plates under cap containing spores.
  • Stipe: Central stalk supporting the pileus.
  • Mycelium: Underground network of thread-like hyphae.
Edible vs Poisonous:

Edible (Agaricus): Dull color, pleasant smell, soft. Poisonous (Amanita): Brightly colored, unpleasant odor, presence of volva (cup at base) and annulus ring.

💡 Exam Tip: Mushrooms reproduce sexually/asexually via spores produced in gills!
Biology

🧬 Evolution

Lamarckism vs. Darwinism:

Lamarckism: Theory of Use & Disuse + Inheritance of Acquired Traits (e.g., giraffe stretched neck passed to offspring). *Disproven.*

Darwinism: Theory of Natural Selection ("Survival of the Fittest"). Environment selects favorable variations.

Darwin's 5 Key Steps:

Overproduction ➔ Struggle for Existence ➔ Variations ➔ Survival of Fittest ➔ Speciation (Origin of New Species).

Fossils: Traces or preserved remains of ancient life in sedimentary rock—acts as direct, undeniable proof of evolution.
💡 Exam Tip: Natural selection works on pre-existing genetic variations, NOT acquired habits!
Physics

🚀 Force and Motion

Newton's Laws of Motion:

  • 1st Law (Inertia): Body maintains rest/uniform motion unless acted on by external net force.
  • 2nd Law ($F=ma$): Acceleration is proportional to force & inversely to mass.
  • 3rd Law: Every action has an equal and opposite reaction.
Equations of Motion:
• v = u + at
• s = ut + ½at²
• v² = u² + 2as
u = initial vel, v = final vel, a = accel, t = time, s = displacement
💡 Exam Tip: Force unit = Newton ($N = kg \cdot m/s^2$). Always convert mass to $kg$!
Physics

⚙️ Machine

MA (Mech Adv): MA = L / E (No Unit)
VR (Vel Ratio): VR = d_e / d_l (No Unit)

Efficiency Formula:

η = (MA / VR) × 100%

Practical machines always have η < 100% because work is lost overcoming friction and lifting moving machine components.

💡 Exam Tip: Friction reduces MA but VR remains CONSTANT for a given machine geometry!
Physics

⚡ Energy

Work Done: W = F × d (Joules, J)
Power: P = W / t (Watts, W)
Kinetic Energy: KE = ½ m v²
Potential Energy: PE = m g h

Law of Conservation of Energy:

Energy cannot be created or destroyed; it only changes from one form to another. Total energy of a closed system remains constant.

💡 Exam Tip: Standard gravity $g = 9.8\text{ m/s}^2$ (or $10\text{ m/s}^2$ if specified in numericals).
Physics

🌊 Wave

Fundamental Wave Equation:
v = f × λ
v = speed (m/s), f = frequency (Hz), λ = wavelength (m)
f = 1 / T (Frequency is inverse of Time Period T)

Transverse Waves: Particles vibrate perpendicular to wave direction (crests & troughs; e.g. Light).

Longitudinal Waves: Particles vibrate parallel to wave direction (compressions & rarefactions; e.g. Sound).

💡 Exam Tip: Wavelength λ is the distance between two consecutive crests or compressions!
Chemistry

⚛️ Atomic Structure & Bond

Bohr-Bury Rule ($2n^2$): Max electrons per shell:

K (n=1)=2 | L (n=2)=8 | M (n=3)=18 | N (n=4)=32

Atomic Number ($Z$): No. of Protons = No. of Electrons.

Mass Number ($A$): Protons + Neutrons.

Chemical Bonding:

Ionic (Electrovalent): Formed by complete transfer of electrons (e.g. $NaCl$, $MgO$). High melting points.

Covalent: Formed by sharing electron pairs (e.g. $H_2O$, $CH_4$, $CO_2$).

💡 Exam Tip: Valence electrons determine bonding behavior. Valency is the octet-seeking capacity!
Chemistry

🧪 Chemical Reaction

4 Primary Types of Reactions:

  • 1. Combination: A + B ➔ AB
  • 2. Decomposition: AB ➔ A + B
  • 3. Displacement: A + BC ➔ AC + B
  • 4. Double Displ.: AB + CD ➔ AD + CB

Exothermic: Heat is released ($\Delta H < 0$). Feels hot. E.g. Combustion, quicklime in water.

Endothermic: Heat is absorbed ($\Delta H > 0$). Feels cold. E.g. Photosynthesis, heating $KClO_3$.

💡 Exam Tip: Always verify that chemical equations are balanced on both reactant and product sides!
Chemistry

💨 Some Gases

Hydrogen ($H_2$):

Zn + 2HCl ➔ ZnCl₂ + H₂↑

Collection: Downward displacement of water.

Test: Burns with a distinct 'POP' sound.

Oxygen ($O_2$):

2KClO₃ ➔[MnO₂, Δ] 2KCl + 3O₂↑

Collection: Downward displacement of water.

Test: Relights a glowing splint.

💡 Exam Tip: $MnO_2$ acts as a catalyst in $O_2$ preparation—it speeds up reaction without being consumed!