Puntos de inflexión en la ciencia

by Vocafy Verificado

Inglés (Estados Unidos) C1 10 preguntas Science History & culture

Explora los experimentos y descubrimientos que transformaron nuestra visión de la vida, la Tierra y el universo, y por qué la evidencia que aportaron fue importante.

1. 1. Elige la respuesta correcta.

   ¿Qué demostró este resultado sobre el crecimiento microbiano?

   Pasteur boiled broth in flasks whose curved necks let air in but trapped dust. The broth remained clear until it came into contact with the trapped dust.

   • Microbes formed spontaneously whenever the broth contained nutrients.
   • Microbial growth resulted from contamination rather than from the broth itself.
   • Boiling made the broth permanently unable to support microbes.
   • Exposure to air alone inevitably produced microbes in the broth.

   El aire podía entrar en el matraz antes de que apareciera cualquier crecimiento.

   Show solution

   • Microbial growth resulted from contamination rather than from the broth itself.

   El cuello curvo separaba la exposición al aire de la exposición al polvo. Esto ayudó a descartar la generación espontánea en las condiciones evaluadas.

2. 2. Elige la respuesta correcta.

   Why would penicillin alone not treat influenza?

   Penicillin disrupts the construction of bacterial cell walls. Viruses have no such walls and reproduce inside host cells.

   • Penicillin cannot reach infections in the respiratory system.
   • The influenza virus has a thicker cell wall than most bacteria.
   • The structure penicillin targets is absent from the influenza virus.
   • Penicillin suppresses symptoms without acting on the cause of an infection.

   Consider whether the treatment's target exists in both kinds of pathogen.

   Show solution

   • The structure penicillin targets is absent from the influenza virus.

   Antibiotics can treat a separate bacterial infection that develops alongside influenza, but they do not cure the flu itself.

3. 3. Elige la respuesta correcta.

   ¿Qué podía concluir Galileo solo a partir de esta observación?

   Galileo observed small objects repeatedly circling Jupiter. They were moons orbiting another planet, not objects traveling around Earth.

   • Some celestial objects orbit a body other than Earth.
   • Every planet must have its own moons.
   • Earth must orbit Jupiter.
   • The Sun must be the center of every orbit.

   Distingue lo que se observó directamente de las afirmaciones más generales sobre todo el sistema solar.

   Show solution

   • Some celestial objects orbit a body other than Earth.

   Las lunas de Júpiter cuestionaron la idea de que todo giraba alrededor de la Tierra. Esta observación por sí sola no demostró que la Tierra orbitara alrededor del Sol.

4. 4. Elige la respuesta correcta.

   ¿Qué explica mejor el aumento de masa del metal?

   Lavoisier heated a metal in a sealed vessel. The metal gained mass, while the total mass of the vessel and everything inside it stayed the same.

   • Heating created new matter that became part of the metal.
   • The metal released some of its matter into the trapped air.
   • Additional matter entered the sealed vessel from the surrounding air.
   • The metal combined with a component of the air already inside the vessel.

   Ten en cuenta tanto el aumento de masa del metal como el hecho de que la masa total no cambió.

   Show solution

   • The metal combined with a component of the air already inside the vessel.

   El metal incorporó oxígeno del aire atrapado. La reacción reorganizó la materia dentro del recipiente en lugar de crear materia nueva.

5. 5. Elige la respuesta correcta.

   ¿Cómo podría cambiar la población a lo largo de varias generaciones?

   A drought left mostly hard seeds on an island. Finches with inherited beak shapes suited to cracking those seeds were more likely to survive and reproduce.

   • Every bird would develop a stronger beak through effort and pass that acquired change to its offspring.
   • Inherited beak shapes suited to hard seeds could become more common.
   • Useful new beak shapes would appear because the birds recognized what they needed.
   • All variation in beak shape would disappear after a single generation.

   Concéntrate en qué aves dejan más descendientes, no en que las aves individuales cambien deliberadamente.

   Show solution

   • Inherited beak shapes suited to hard seeds could become more common.

   La selección natural cambia la frecuencia de los rasgos heredados. No requiere que los organismos anticipen qué les ayudaría a sobrevivir.

6. 6. Elige la respuesta correcta.

   ¿Qué proceso explica mejor ambos patrones?

   Ocean-floor rocks show matching bands of magnetic direction on opposite sides of a mid-ocean ridge. The rocks also become progressively older farther from the ridge.

   • Old ocean crust moves toward the ridge and melts at its center.
   • New ocean crust forms near continental margins and moves inward toward the ridge.
   • New ocean crust forms at the ridge and moves outward on both sides.
   • The ocean floor remains stationary while all its rocks continually adopt the current magnetic direction.

   Las rocas más jóvenes indican dónde se está agregando material nuevo.

   Show solution

   • New ocean crust forms at the ridge and moves outward on both sides.

   La lava, al enfriarse, conserva la dirección del campo magnético de la Tierra. Las bandas coincidentes se convirtieron en una prueba contundente de la expansión del fondo oceánico y de la tectónica de placas.

7. 7. Elige la respuesta correcta.

   ¿Qué hizo que esto marcara un punto de inflexión en la medición del tiempo geológico?

   Radioactive atoms change into other kinds of atoms at known rates. By measuring their proportions in suitable minerals and accounting for the sample's history, scientists can estimate when those minerals formed.

   • It provided a physical clock independent of human records.
   • It established that every rock on Earth formed at the same moment.
   • It made a rock's age depend only on how deeply it was buried.
   • It removed the need to investigate whether a sample had been altered.

   Considera qué conecta la medición con el tiempo transcurrido.

   Show solution

   • It provided a physical clock independent of human records.

   La datación radiométrica abrió una ventana a épocas muy anteriores a la historia escrita. La fecha de un mineral no representa automáticamente la edad de la Tierra misma.

8. 8. Elige la respuesta correcta.

   ¿Qué conclusión está mejor respaldada para estos virus?

   Researchers separately tagged the DNA and protein coats of viruses that infect bacteria. During infection, the DNA label mainly entered the cells, while the protein label largely stayed outside. The infected cells then produced new viruses.

   • Every kind of virus stores its genetic information in DNA.
   • Proteins have no role in any stage of viral reproduction.
   • The bacteria supplied all the genetic instructions without receiving viral material.
   • DNA, rather than the outer protein coat, carries inherited instructions in this viral system.

   Mantén la conclusión dentro del alcance del sistema estudiado.

   Show solution

   • DNA, rather than the outer protein coat, carries inherited instructions in this viral system.

   Este experimento ayudó a establecer el papel del ADN en la herencia. Algunos otros virus usan ARN, por lo que el hallazgo no debe extenderse a todos los virus.

9. 9. Elige la respuesta correcta.

   ¿Qué explicación se ajusta mejor a estas observaciones?

   On a particular metal surface, intense red light released no electrons, while faint ultraviolet light did. Increasing the ultraviolet light's intensity released more electrons but did not raise their maximum energy.

   • Light releases electrons whenever its total intensity is high enough, regardless of frequency.
   • Light transfers energy in individual packets whose energy depends on frequency.
   • Every color of light delivers individual packets with the same energy.
   • Increasing intensity raises the energy of each light packet without changing the number of packets.

   Distingue la cantidad de luz que llega de la energía transferida en cada interacción.

   Show solution

   • Light transfers energy in individual packets whose energy depends on frequency.

   La luz más brillante aporta más fotones; la luz de mayor frecuencia aporta más energía por fotón. Liberar un electrón requiere una energía mínima por fotón.

10. 10. Elige la respuesta correcta.

    ¿Cómo cambió la relatividad el estatus de la teoría de Newton?

    Newton's laws give highly accurate predictions at ordinary speeds and in weak gravitational fields. Relativity explains measurable differences at very high speeds or in strong gravity while closely matching Newton's predictions in everyday conditions.

    • It showed that Newton's theory and relativity are equally precise under every condition.
    • It made Newton's agreement with everyday observations irrelevant to the theory's usefulness.
    • It defined the conditions in which Newton's theory remains a reliable approximation.
    • It established that any theory useful in daily life must also be exact in extreme conditions.

    Un modelo puede tener límites sin perder todo su valor práctico.

    Show solution

    • It defined the conditions in which Newton's theory remains a reliable approximation.

    El progreso científico puede ampliar un modelo anterior en lugar de eliminarlo. Los ingenieros siguen usando las leyes de Newton cuando los efectos relativistas son demasiado pequeños como para ser relevantes.