6th Grade Science (Earth Science) practice questions and exam guide

What happens at a TRANSFORM plate boundary?

1. Plates collide
2. Plates slide past each other horizontally — typically causes earthquakes (e.g., the San Andreas Fault in California)
3. Plates separate
4. Plates rise

Answer: B — Plates slide past each other horizontally — typically causes earthquakes (e.g., the San Andreas Fault in California)

Transform = lateral sliding. (A) is convergent; (C) is divergent; (D) is wrong.

A student says the ribosome 'controls everything the cell does.' What is the off-by-one error here?

1. Ribosomes build proteins; it is the NUCLEUS that contains the DNA controlling cell activity
2. Ribosomes control digestion; the lysosome controls everything else
3. Ribosomes control movement; the cytoskeleton handles proteins
4. The student is correct

Answer: A — Ribosomes build proteins; it is the NUCLEUS that contains the DNA controlling cell activity

A) Common organelle mix-up: ribosomes assemble proteins, the nucleus is the control center. B/C) Wrong organelles. D) Incorrect.

Speed is calculated as:

1. Distance × time
2. Distance ÷ time
3. Time ÷ distance
4. Mass × velocity

Answer: B — Distance ÷ time

B) Speed = distance / time. A/C) Reversed/wrong operation. D) Momentum.

Climate change refers to:

1. Day-to-day weather
2. Long-term changes in average temperature, precipitation, and other climate variables — currently driven primarily by human-caused increases in greenhouse gas concentrations
3. Volcanoes alone
4. Solar activity alone

Answer: B — Long-term changes in average temperature, precipitation, and other climate variables — currently driven primarily by human-caused increases in greenhouse gas concentrations

Climate change = long-term shifts. (A), (C), (D) misread.

In photosynthesis, plants take in:

1. Oxygen and release carbon dioxide
2. Nitrogen and release water
3. Glucose and release light
4. Carbon dioxide and water; release oxygen

Answer: D — Carbon dioxide and water; release oxygen

D) Inputs: CO₂ + H₂O + light → glucose + O₂. A) Reversed direction — that's respiration. B/C) Wrong reactants/products.

Our solar system is centered on:

1. Earth
2. Jupiter
3. The Moon
4. The Sun, a medium-sized star

Answer: D — The Sun, a medium-sized star

Heliocentric system. (A) is geocentric (incorrect); (C), (B) misread.

The water cycle (hydrologic cycle) includes:

1. Only evaporation
2. Only rain
3. Evaporation, condensation, precipitation, runoff/groundwater flow, and transpiration — a continuous cycle moving water through atmosphere, surface, and oceans
4. Just rivers

Answer: C — Evaporation, condensation, precipitation, runoff/groundwater flow, and transpiration — a continuous cycle moving water through atmosphere, surface, and oceans

Water cycle has multiple components. (A), (B), (D) are partial.

Air masses tend to move:

1. From high-pressure regions toward low-pressure regions
2. In random directions with no driver
3. Only at night
4. Only over the ocean

Answer: A — From high-pressure regions toward low-pressure regions

A) Pressure gradients drive winds. B) Pressure systems are highly directional. C/D) No diurnal or location restriction.

A front is:

1. A type of cloud
2. A type of storm
3. The boundary between two air masses with different temperatures, humidity, or density — fronts often produce changing weather (rain, storms, clearing)
4. The center of a hurricane

Answer: C — The boundary between two air masses with different temperatures, humidity, or density — fronts often produce changing weather (rain, storms, clearing)

Fronts are air-mass boundaries. (A), (B), (D) misread.

Conservation of energy:

1. Has no rule
2. Energy disappears
3. Energy is created
4. Energy cannot be created or destroyed — only transformed

Answer: D — Energy cannot be created or destroyed — only transformed

D) Standard law. A/B/C) Each is incorrect.

Photosynthesis converts:

1. Light energy + CO₂ + water → glucose + O₂
2. Glucose → CO₂ + water
3. Light to heat only
4. Has no equation

Answer: A — Light energy + CO₂ + water → glucose + O₂

A) Standard. B) Cellular respiration. C/D) Each is incorrect.

How can humans mitigate the impact of natural hazards?

1. Ignore them
2. Through prediction (early warnings), preparation (drills, supplies), building design (earthquake-resistant structures, flood barriers), zoning (not building in flood plains), and public education
3. Hope only
4. Only relocation

Answer: B — Through prediction (early warnings), preparation (drills, supplies), building design (earthquake-resistant structures, flood barriers), zoning (not building in flood plains), and public education

Multi-strategy mitigation. (A), (C), (D) understate.

What happens at a 'transform' plate boundary?

Plates slide PAST each other horizontally. Causes earthquakes (San Andreas Fault).

What are 'tectonic plates'?

Huge slabs of Earth's crust + upper mantle. They float and move on the molten layer beneath.

WORKED EXAMPLE: A food chain begins with grass producing 10,000 kcal of energy. Using the 10% rule, how much energy reaches a hawk at trophic level 4 (grass → grasshopper → frog → hawk)?

Step 1: Recall the 10% rule. Only ~10% of energy passes to the next trophic level; the rest is lost as heat. Step 2: Trophic level 1 (grass) = 10,000 kcal. Step 3: Trophic level 2 (grasshopper) = 10,000 × 0.10 = 1,000 kcal. Step 4: Trophic level 3 (frog) = 1,000 × 0.10 = 100 kcal. Step 5: Trophic level 4 (hawk) = 100 × 0.10 = 10 kcal. Step 6: Check direction of energy flow — arrows point FROM prey TO predator (energy flows up). Answer: 10 kcal reaches the hawk.

What's the difference between a planet and a star?

Stars produce their own light from nuclear fusion. Planets reflect light from a star.

What causes earthquakes?

Sudden movement along plate boundaries or faults. Stored energy releases as seismic waves.

WORKED EXAMPLE: Calculate the work done when a force of 5 N moves an object 10 m.

Step 1: Recall the work formula. W = F × d (force times distance, in the direction of the force). Step 2: Identify values. F = 5 N, d = 10 m. Step 3: Multiply. 5 × 10 = 50. Step 4: Attach units. 1 N·m = 1 joule (J). Work = 50 J. Step 5: Reasonableness check. A small push of 5 N over 10 m gives a moderate 50 J — comparable to lifting a small book about 5 m.