Science Flashcards

Which of the following best describes a food chain?

Answer: A sequence showing how energy flows between organisms

A food chain shows the linear transfer of energy from one organism to the next, starting with a producer and ending with a top consumer.

What is the atomic number of an element?

Answer: The number of protons in the nucleus

The atomic number is the number of protons in an element's nucleus and uniquely identifies each element on the periodic table.

Which phenomenon explains why a straw appears bent when placed in a glass of water?

Answer: Refraction

Refraction occurs when light changes speed as it crosses the boundary between air and water, bending the light rays and making the straw appear bent.

What is the main source of energy for the Earth's weather systems?

Answer: Solar radiation from the Sun

Solar radiation from the Sun drives weather patterns by heating the atmosphere and oceans unevenly, causing air and water movement.

Which of the following represents a balanced chemical equation?

Answer: 2H₂ + O₂ → 2H₂O

2H₂ + O₂ → 2H₂O is balanced because it has 4 hydrogen atoms and 2 oxygen atoms on both sides of the equation.

What is the term for organisms that break down dead organic matter and return nutrients to the soil?

Answer: Decomposers

Decomposers such as bacteria and fungi break down dead organisms and organic waste, recycling nutrients back into the ecosystem.

Which property of a wave determines its pitch when heard as sound?

Answer: Frequency

Frequency, measured in hertz (Hz), determines pitch; higher frequency sound waves produce higher-pitched sounds.