Science gr.9 Flashcards

Question

How to Calculating Perfect Efficiency

Answer 1

Perfect efficiency occurs when all input energy is converted into useful work without losses. In practical scenarios, efficiency is calculated as: Efficiency= Input Energy / Useful Output Energy ×100%

Answer 2

Differences Series Circuits:Components are connected end-to-end. Parallel Circuits:Components are connected across common points. Series circuits can be likened to a single-lane road where traffic must pass through one point at a time. Parallel circuits can be compared to multiple lanes on a highway allowing simultaneous travel.

Answer 3

Biosphere: The zone of life on Earth, encompassing all living organisms. Atmosphere: The layer of gases surrounding the planet, essential for weather and climate. Lithosphere: The solid outer part of the Earth, including rocks and soil. Hydrosphere: All water bodies on Earth, including oceans, rivers, and groundwater.

Answer 4

Abiotic Factors: Non-living components that affect ecosystems (e.g., temperature, water, sunlight). Biotic Factors: Living components that influence ecosystems (e.g., plants, animals, bacteria).

Answer 5

Photosynthesis: the process by which plants use sunlight, water, and carbon dioxide to create oxygen and energy in the form of sugar. Chemical Equation: Carbon dioxide + water + sunlight →glucose + oxygen Cellular Respiration: Process by which organisms convert glucose into usable energy. Chemical Equation: Glucose + oxygen →carbon dioxide + water + energy

Answer 6

Definitions Food Chain: A linear sequence showing how energy and nutrients flow from one organism to another. Food Web: A complex network of interconnected food chains.

Answer 7

Producers: Organisms that create their own food (e.g., plants). Consumers: Herbivores: Eat plants (e.g., rabbits). Carnivores: Eat other animals (e.g., lions). Omnivores: Eat both plants and animals (e.g., bears). Scavengers: Consume dead organisms (e.g., vultures). Decomposers: Break down dead matter (e.g., fungi, bacteria).

Answer 8

Types of Ecological Pyramids Pyramid of Energy: Represents energy flow; always upright as energy decreases at each trophic level. Pyramid of Numbers: Shows the number of organisms at each trophic level; can be upright or inverted depending on the ecosystem. Pyramid of Biomass: Represents the total mass of living organisms; can also be upright or inverted based on specific ecosystems.

Answer 9

Biotic Influences Examples include competition for resources, predation, and disease. These factors can affect population sizes and community dynamics. Abiotic Influences Include temperature, light intensity, water availability, and soil composition. Changes in these factors can limit species distribution and abundance.

Answer 10

Types of Succession Primary Succession: Occurs in lifeless areas where soil has not yet formed (e.g., after a volcanic eruption). Secondary Succession: Occurs in areas where a disturbance has destroyed an existing community but soil remains (e.g., after a forest fire).

Answer 11

Ecosystems tend toward a state of equilibrium where species populations stabilize over time.

Answer 12

Human activities such as burning fossil fuels increase carbon dioxide levels in the atmosphere, contributing to climate change. This affects global temperatures and weather patterns, impacting ecosystems worldwide.

Answer 13

Stars: Massive balls of hot gases that produce their own light and energy through nuclear fusion (e.g., the Sun). Planets: Large, spherical objects that orbit stars. There are eight planets in our solar system, including Earth. Moons: Natural satellites that orbit planets (e.g., Earth's Moon). Galaxies: Vast collections of stars, gas, and dust held together by gravity; the Milky Way is our galaxy. Asteroid Belt: A region between Mars and Jupiter filled with rocky bodies called asteroids. Meteoroids: Small fragments from comets or asteroids that can enter Earth's atmosphere. Comets: Icy bodies that release gas or dust when close to the Sun, forming a tail.

Answer 14

The Sun converts hydrogen into helium through nuclear fusion in its core, generating immense energy that radiates as heat and light. This process sustains life on Earth by providing warmth, driving climate, and enabling photosynthesis.

Answer 15

Kilometers (km): Standard unit for measuring distances on Earth. Astronomical Unit (AU): Average distance from Earth to the Sun, approximately 149.6 million km Light Year (ly): Distance light travels in one year, about 9.46 trillion km. Astronomy is the study of everything in the universe beyond Earth's atmosphere

Answer 16

Rotation: The spinning of Earth on its axis takes about 24 hours, causing day and night. Orbit: Earth's revolution around the Sun takes about one year, leading to seasonal changes due to its axial tilt (approximately 23.5∘).

Answer 17

Heliocentric: Sun at the center; planets orbit it. Geocentric: Earth at the center; all celestial bodies orbit it.

Answer 18

Seasons are caused by Earth's axial tilt as it orbits the Sun. Solar Eclipse: Occurs when the Moon passes between Earth and the Sun. Lunar Eclipse: Occurs when Earth passes between the Sun and the Moon.

Answer 19

Constellations are patterns formed by stars in the night sky, used for navigation and storytelling. Some prominent constellations include Orion, Big Dipper, and Canis Major.

Answer 20

The Big Bang Theory posits that the universe began from a singular point and has been expanding ever since. Evidence for this expansion includes:Red Shift