Science Flashcards

What is the chemical formula for water?

Answer: H2O

The chemical formula for water is H2O. This formula indicates that each molecule of water is composed of two hydrogen atoms (H) bonded to one oxygen atom (O). It is a fundamental and widely recognized chemical compound essential for all known forms of life.

What is the process by which plants make their food?

Answer: Photosynthesis

Plants produce their own food through a vital process called photosynthesis. During photosynthesis, plants use sunlight, water, and carbon dioxide to create glucose (sugar) for energy and release oxygen as a byproduct. This process is fundamental to sustaining life on Earth, as it forms the base of most food chains.

What is the primary source of energy for the Earth?

Answer: The Sun

The Sun is the primary and most significant source of energy for Earth. Its radiant energy, in the form of sunlight, drives nearly all natural processes, including photosynthesis in plants, weather patterns, and the water cycle. This solar energy is ultimately responsible for sustaining life and powering most ecosystems on our planet.

What is the boiling point of water at sea level?

Answer: 100°C

At standard atmospheric pressure, which is typically found at sea level, the boiling point of pure water is 100 degrees Celsius (°C). At this temperature, water transitions from a liquid to a gaseous state (steam). This is a fundamental physical property of water.

What is the most abundant gas in Earth's atmosphere?

Answer: Nitrogen

Nitrogen is the most abundant gas in Earth's atmosphere, making up approximately 78% of its total volume. While oxygen is crucial for respiration, nitrogen plays a significant role in various biological and atmospheric processes. It is a relatively inert gas but essential for life through the nitrogen cycle.

What is the Earth's core primarily composed of?

Answer: Iron and Nickel

The Earth's core is primarily composed of a dense mixture of iron and nickel. The outer core is liquid, while the inner core is solid due to immense pressure, despite extremely high temperatures. This metallic composition is responsible for generating Earth's magnetic field.

What type of bond forms when electrons are shared between atoms?

Answer: Covalent Bond

Covalent bonds are formed when two atoms share one or more pairs of electrons to achieve a stable electron configuration, typically a full outer shell. This sharing creates a strong attractive force holding the atoms together. In contrast, ionic bonds involve the transfer of electrons, and metallic bonds involve a 'sea' of delocalized electrons.

What is the unit of force in the metric system?

Answer: Newton

The Newton (N) is the standard unit of force in the International System of Units (SI), which is the modern form of the metric system. It is defined as the force required to accelerate a mass of one kilogram at a rate of one meter per second squared. Other options like Joule, Pascal, and Watt are units for energy, pressure, and power, respectively.

What is the main purpose of the digestive system?

Answer: To break down food and absorb nutrients

The digestive system's primary role is to process the food we eat. This involves both mechanical breakdown (chewing, churning) and chemical breakdown (enzymes) to convert complex food molecules into simpler nutrients. These nutrients are then absorbed into the bloodstream and transported to cells throughout the body for energy, growth, and repair.