Hypothesis Lab

Pregunta 3 (Respuesta Vegetal y Fototropismo — Examen Estatal de NY) Iniciador de Oración 3 de 3

Los estudiantes colocaron diez plántulas de frijol en una caja oscura con un orificio lateral por donde entra luz solar directa. Otro grupo de diez plántulas recibió luz uniforme desde arriba. Tras 5 días, midieron el ángulo de curvatura del tallo (grados hacia la luz).

Completa la hipótesis comprobable:

Si las plántulas de frijol reciben luz solar desde una sola dirección,
entonces los tallos se
porque las hormonas vegetales estimulan la elongación celular en el lado .

Pregunta 4 (Respiración Celular en Levadura — Examen Estatal de NY) Sin Iniciador

Se prepararon matraces con cantidades idénticas de levadura y agua, pero con diferentes concentraciones de glucosa: 0%, 2%, 5% y 10%. Se colocó un globo en la boca de cada matraz para recolectar el dióxido de carbono producido tras 30 minutos a 30°C.

VI:

VD:

Escribe tu hipótesis comprobable (Si... entonces... porque...):

Ciencias Grado 8 • Investigaciones Biológicas Estatales de NY Página 2 de 5

Laboratorio de Hipótesis • Cuerpo Humano y Evolución Preguntas 5 – 7

Pregunta 5 (Frecuencia Cardíaca y Ejercicio — Examen Estatal de NY) Sin Iniciador

Los estudiantes midieron su pulso en reposo (latidos por minuto). Luego realizaron saltos de tijera durante 1 minuto, 3 minutos y 5 minutos en días diferentes. Inmediatamente después de cada sesión, registraron su pulso y el tiempo de recuperación al valor basal.

VI:

VD:

Escribe tu hipótesis comprobable (Si... entonces... porque...):

Pregunta 6 (Germinación y Salinidad del Suelo — Examen Estatal de NY) Sin Iniciador

La sal vial llega al suelo junto a las carreteras de Nueva York cada invierno. Científicos de 8.° grado probaron soluciones de 0%, 1%, 3% y 5% de cloruro de sodio en 50 semillas de rábano en placas de Petri. A los 7 días, contaron el porcentaje de semillas germinadas.

VI:

VD:

Escribe tu hipótesis comprobable (Si... entonces... porque...):

Pregunta 7 (Resistencia a Antibióticos — Examen Estatal de NY) Sin Iniciador

Bacterias cultivadas en agar fueron tratadas con discos empapados en penicilina (0 mg/mL, 10 mg/mL y 50 mg/mL). Los científicos midieron la "zona de inhibición" transparente (diámetro en mm) donde las colonias bacterianas murieron.

VI:

VD:

Escribe tu hipótesis comprobable (Si... entonces... porque...):

Ciencias Grado 8 • Investigaciones Biológicas Estatales de NY Página 3 de 5

Laboratorio de Hipótesis • Ecosistemas y Herencia Preguntas 8 – 10

Pregunta 8 (Depredador y Presa: Lince y Liebre — Examen NY) Sin Iniciador

Investigadores rastrearon poblaciones de linces y liebres americanas en un bosque de Adirondack durante 20 años. Cuando la liebre alcanzó su pico poblacional, registraron los cambios en la tasa de nacimientos y el tamaño de la población de linces en los dos años siguientes.

VI:

VD:

Escribe tu hipótesis comprobable (Si... entonces... porque...):

Pregunta 9 (Fertilizantes y Ecosistemas Acuáticos — Examen NY) Sin Iniciador

Estudiantes modelaron la escorrentía hacia el Lago Ontario. Llenaron cuatro acuarios con agua de estanque y añadieron 0 mL, 5 mL, 15 mL y 30 mL de fertilizante nitrogenado. Durante 14 días, midieron el oxígeno disuelto (ppm) y la turbidez del agua.

VI:

VD:

Escribe tu hipótesis comprobable (Si... entonces... porque...):

Pregunta 10 (Genética en Plantas de Guisante — Examen NY) Sin Iniciador

Un estudiante cruzó plantas de guisante puras altas (TT) con enanas (tt). Todos los descendientes de la generación 1 fueron altos (Tt). Cuando estas se autopolinizaron para producir la generación 2 (200 descendientes), registró el recuento de plantas altas versus enanas.

VI:

VD:

Escribe tu hipótesis comprobable (Si... entonces... porque...):

Ciencias Grado 8 • Investigaciones Biológicas Estatales de NY Página 4 de 5

Laboratorio de Hipótesis • Respiración, Conducta y Ecología Preguntas 11 – 13

Pregunta 11 (Temperatura del Agua y Peces — Examen NY) Sin Iniciador

Peces dorados fueron colocados en tanques a cuatro temperaturas: 10°C, 16°C, 22°C y 28°C. Los estudiantes contaron las aperturas del opérculo branquial por minuto para medir la tasa de respiración del pez según cambiaba la temperatura.

VI:

VD:

Escribe tu hipótesis comprobable:

Pregunta 12 (Conducta Animal y Humedad — Examen NY) Sin Iniciador

Estudiantes colocaron 20 lombrices en el centro de una bandeja con dos lados. El Lado A contenía toallas de papel secas; el Lado B toallas húmedas. Tras 15 minutos en oscuridad, registraron la ubicación final de todas las lombrices.

VI:

VD:

Escribe tu hipótesis comprobable:

Pregunta 13 (Descomposición y Temperatura del Suelo — Examen NY) Sin Iniciador

Bolsas de malla con 50 gramos de hojas de arce caídas fueron enterradas en parcelas de suelo a 5°C, 15°C y 25°C. A los 60 días, se extrajeron y midió la masa perdida de hojas (g) por descomposición de hongos y bacterias.

VI:

VD:

Escribe tu hipótesis comprobable:

Lista de Cotejo y Autoevaluación

Verifica que tus 13 hipótesis cumplan con los estándares del examen estatal:

Identifiqué la VI

Predije la VD

Di razón biológica

Ciencias Grado 8 • Investigaciones Biológicas Estatales de NY Página 5 de 5

Question 6: Radish Seed Germination & Salinity

IV: Concentration of sodium chloride salt solution (0%, 1%, 3%, 5%).
DV: Percentage of seeds that successfully germinate.
Exemplar Hypothesis: If the salt concentration of the water increases, then the percentage of germinated radish seeds will decrease because excess salt creates a hypertonic environment that draws water out of seed embryos by osmosis.

Question 7: Antibiotic Concentration & Bacterial Growth

IV: Concentration of penicillin antibiotic (0, 10, 50 mg/mL).
DV: Diameter of zone of inhibition (mm of cleared bacteria).
Exemplar Hypothesis: If the concentration of penicillin increases, then the zone of inhibition will become larger because higher antibiotic doses inhibit more bacterial cell wall synthesis, destroying non-resistant bacteria.

Question 8: Predator-Prey (Lynx & Snowshoe Hare)

IV: Abundance / population size of snowshoe hare prey.
DV: Lynx kit survival rate / total lynx population size.
Exemplar Hypothesis: If the snowshoe hare population increases, then the lynx population will increase in subsequent years because more prey provides necessary food energy to support higher predator reproductive and kit survival rates.

Question 9: Fertilizer Runoff & Lake Water Quality

IV: Amount of nitrogen fertilizer added (0 mL, 5 mL, 15 mL, 30 mL).
DV: Dissolved oxygen level (ppm) / water turbidity.
Exemplar Hypothesis: If the volume of fertilizer runoff increases, then dissolved oxygen levels will drop over 14 days because rapid algae blooms die and decompose, and aerobic decomposers consume available dissolved oxygen.

Hypothesis Lab • Teacher Answer Key Page 2 of 3

Hypothesis Lab • Teacher Answer Key (Questions 10 – 13 & Exit Ticket) Teacher Resource

Question 10: Pea Plant Genetics (Mendelian Cross)

IV: Allele combinations inherited from heterozygous parents (Tt x Tt). • DV: Ratio of tall to dwarf offspring.
Exemplar Hypothesis: If heterozygous tall pea plants (Tt) cross, then approximately 75% of offspring will be tall and 25% dwarf (3:1 ratio) because tall (T) is dominant and dwarf (t) is expressed only in homozygous recessive (tt) offspring.

Question 11: Water Temperature & Fish Gill Movement

IV: Water temperature (10°C, 16°C, 22°C, 28°C). • DV: Gill operculum openings per minute.
Exemplar Hypothesis: If water temperature increases, then gill movement rate will increase because fish metabolic rates rise in warmer water, and warmer water holds less dissolved oxygen, requiring faster breathing.

Question 12: Earthworm Moisture Taxis

IV: Moisture condition of substrate (dry vs. damp). • DV: Number of earthworms found in each chamber.
Exemplar Hypothesis: If earthworms choose between dry and damp paper towels, then significantly more worms will move to the damp side because earthworms breathe through moist skin and dry environments cause fatal dehydration.

Question 13: Leaf Litter Decomposition & Soil Temperature

IV: Soil plot temperature (5°C, 15°C, 25°C). • DV: Mass of leaf litter lost (grams).
Exemplar Hypothesis: If soil temperature increases, then leaf litter mass loss will be greatest at 25°C because bacterial and fungal decomposers have higher metabolic rates in warmer conditions.

Exit Ticket Key: Dialysis Tubing Osmosis 10 Points Total

Part A1 (IV): Concentration / type of solution outside the bag (0% water, 5% glucose, 20% salt).

Part A2 (DV): Final mass of the dialysis bag (grams) / change in mass.

Part C (Constant): Same initial volume of starch (10 mL), same tubing material, same temperature (22°C), same time (45 min).

Part C (Reasoning): Water moved out into the hypertonic 20% salt solution where water concentration was lower.

Part B Exemplar Hypothesis: If a starch dialysis bag is placed in a 20% salt solution, then the mass of the bag will decrease because water moves out of the bag by osmosis toward the higher solute salt solution.

Hypothesis Lab • Teacher Answer Key Page 3 of 3

Hypothesis Lab Teacher Guide • NYS Grade 8 Science Page 1 of 2

Hypothesis Lab • Section 2: Facilitation & Differentiation Teacher Resource

Target Academic Vocabulary (NYS Intermediate Science Standards)

Independent Variable:

The experimental factor intentionally changed or manipulated by the experimenter (cause).

Dependent Variable:

The measurable response or outcome observed and recorded in data tables (effect).

Controlled Constant:

Any condition deliberately kept identical across all test groups to ensure a fair test.

Osmosis & Diffusion:

Passive movement of water molecules across a semipermeable cell membrane from high to low water concentration.

Enzyme (Catalyst):

A protein molecule that speeds up specific biochemical reactions; sensitive to pH and temperature changes.

Cellular Respiration:

The biochemical process breaking down glucose with oxygen to produce usable ATP cellular energy and CO₂.

Tiered Differentiation & ELL/IEP Accommodations

Tier 1: ELL / Emerging

• Provide visual variable cards ("Cause / IV" and "Effect / DV").
• Extend the sentence starter template through Q6 if needed.
• Allow bilingual science glossary for vocabulary like osmosis.

Tier 2: On-Grade Mastery

• Transition completely off sentence starters by Q4.
• Require quantitative units in hypotheses (e.g., bpm, mL, mm).
• Identify 2 controlled constants per scenario.

Tier 3: Advanced / Honors

• Sketch predicted data graph lines (X-axis = IV, Y-axis = DV).
• Explain molecular mechanisms (e.g., enzyme denaturation at high heat).
• Propose a follow-up control group for Q9 and Q13.

Targeted Circulation Questioning Stems:

• "If I look at this data table, which column did the student choose to set up beforehand?"
• "Can you underline the biological explanation in your hypothesis? Why does that happen inside the cell?"
• "If we did not keep temperature constant in this test, how would that compromise the validity of the results?"

Hypothesis Lab Teacher Guide • NYS Grade 8 Science Page 2 of 2

Question 3 (Plant Response & Phototropism — NYS Grade 8 Exam) Sentence Starter 3 of 3

Students placed ten identical bean seedlings in a dark cardboard box with a single circular opening on the right side allowing directional sunlight to enter. A second group of ten bean seedlings was placed under even overhead grow lights. After 5 days, students measured the angle of stem curvature (degrees toward the light).

Complete the testable hypothesis:

If bean seedlings receive light from only one direction,
then the stems will
because plant hormones stimulate cell elongation on the side.

Question 4 (Cellular Respiration in Yeast — NYS Grade 8 Exam) No Starter

Flasks were prepared with identical amounts of yeast and water, but different concentrations of dissolved glucose: 0%, 2%, 5%, and 10%. A rubber balloon was attached over each flask mouth to capture the carbon dioxide gas produced after 30 minutes at 30°C.

IV:

DV:

Write your testable hypothesis (If... then... because...):

Grade 8 Science • NYS Statewide Biology Investigations Page 2 of 5

Hypothesis Lab • Section 2: Human Body & Evolution Questions 5 – 7

Question 5 (Human Heart Rate & Exercise — NYS Grade 8 Exam) No Starter

Students measured their resting pulse rate in beats per minute (bpm). Each student performed jumping jacks for 1 minute, 3 minutes, and 5 minutes on separate days. Immediately following each exercise session, they recorded their post-exercise pulse rate and recovery time.

IV:

DV:

Write your testable hypothesis (If... then... because...):

Question 6 (Seed Germination & Soil Salinity — NYS Grade 8 Exam) No Starter

Road salt washes into soil near New York highways every winter. Eighth-grade scientists tested how soil salt levels affect crop seeds. They placed 50 radish seeds in Petri dishes watered with solutions of 0%, 1%, 3%, and 5% sodium chloride. After 7 days, they counted the percentage of germinated seeds.

IV:

DV:

Write your testable hypothesis (If... then... because...):

Question 7 (Antibiotic Resistance & Bacteria — NYS Grade 8 Exam) No Starter

Bacteria cultured on agar plates were treated with paper disks soaked in three concentrations of penicillin (0 mg/mL, 10 mg/mL, and 50 mg/mL). Scientists measured the clear "zone of inhibition" (diameter in mm) where bacterial colonies were killed.

IV:

DV:

Write your testable hypothesis (If... then... because...):

Grade 8 Science • NYS Statewide Biology Investigations Page 3 of 5

Hypothesis Lab • Section 3: Ecosystems & Heredity Questions 8 – 10

Question 8 (Predator-Prey Population Dynamics — NYS Grade 8 Exam) No Starter

Ecology researchers tracked Canada lynx (predator) and snowshoe hare (prey) populations in an Adirondack forest reserve over 20 years. When the snowshoe hare population peaked due to abundant vegetation, researchers recorded changes in the lynx birth rate and population size over the next two years.

IV:

DV:

Write your testable hypothesis (If... then... because...):

Question 9 (Fertilizer Runoff & Lake Ecology — NYS Grade 8 Exam) No Starter

Students modeled lawn runoff into Lake Ontario. They filled four aquariums with pond water and added 0 mL, 5 mL, 15 mL, and 30 mL of liquid nitrogen fertilizer. Over 14 days, they measured the dissolved oxygen level (ppm) and water turbidity.

IV:

DV:

Write your testable hypothesis (If... then... because...):

Question 10 (Inherited Traits in Pea Plants — NYS Grade 8 Exam) No Starter

A student crossed purebred tall pea plants (TT) with purebred dwarf pea plants (tt). All offspring in generation 1 were tall (Tt). When generation 1 plants self-pollinated to produce generation 2 (200 offspring total), the student recorded the exact count of tall versus dwarf plants.

IV:

DV:

Write your testable hypothesis (If... then... because...):

Grade 8 Science • NYS Statewide Biology Investigations Page 4 of 5

Hypothesis Lab • Section 4: Respiration, Behavior & Ecology Questions 11 – 13

Question 11 (Water Temp & Fish Respiration — NYS Grade 8 Exam) No Starter

Goldfish were placed in controlled water tanks at four temperatures: 10°C, 16°C, 22°C, and 28°C. Students counted the number of gill operculum openings per minute to measure the fish respiration rate as water temperature changed.

IV:

DV:

Write your testable hypothesis:

Question 12 (Animal Behavior & Moisture — NYS Grade 8 Exam) No Starter

Students placed 20 earthworms in the center of a two-chambered tray. Side A contained dry paper towels; Side B contained damp paper towels. The chamber was covered to exclude light. After 15 minutes, students recorded the final location of all earthworms.

IV:

DV:

Write your testable hypothesis:

Question 13 (Decomposition Rate & Soil Temperature — NYS Grade 8 Exam) No Starter

Nylon mesh litterbags containing 50 grams of fallen maple leaves were buried in forest soil plots kept at 5°C, 15°C, and 25°C. After 60 days, researchers retrieved the bags and measured the leaf mass lost (g) from fungal and bacterial decomposition.

IV:

DV:

Write your testable hypothesis:

Self-Assessment Checklist

Check off each criteria to confirm your 13 hypotheses are exam-ready:

Identified IV correctly

Predicted DV direction

Gave biological cause

Grade 8 Science • NYS Statewide Biology Investigations Page 5 of 5