science_notes yr10 sem 2 alnoori

Force

A push, pull, or twist.

Mass

The amount of matter in an object, measured in kilograms.

Acceleration

A change in speed or direction of motion over time.

Newton's second law

The relationship between force, mass, and acceleration, stated as F=MA.

Weight

The measure of how hard gravity pulls down on an object, measured in Newtons.

Distance

The amount of space between two points.

Speed

The distance an object travels divided by the time taken.

Average speed

The total distance divided by the total time taken.

Instantaneous speed

The speed at a particular instant of time.

Displacement

The distance an object is from its starting position.

Velocity

The measure of how much displacement changes in a certain time.

Distance-Time graph

A graph that shows the relationship between distance and time.

Displacement-Time graph

A graph that shows the relationship between displacement and time.

Speed-Time graph

A graph that shows the relationship between speed and time.

Net force

The sum of all the forces acting on an object.

Friction

A contact force that opposes motion, caused by objects rubbing against each other.

Isaac Newton

An English scientist who formulated the three laws of motion.

Newton's first law

An object stays at rest or at the same speed unless an unbalanced force acts upon it.

Newton's third law

For every action, there is an equal and opposite reaction.

Nebula

A vast region of gas and dust in space.

Supernova

An explosion of a massive star at the end of its life.

Neutron star

An extremely dense star left over after a supernova.

Red giant

A star that has stopped fusing hydrogen in its core.

White dwarf

A small, very dense star formed at the end of a small star's lifetime.

Gravity

The force of attraction experienced between any two objects in the universe.

Nuclear fusion

The process in which hydrogen atoms fuse to form helium atoms, creating heat and light in stars.

Gravity

The force that attracts objects with mass towards each other.

Radiation pressure

The outward force caused by the heat radiated from nuclear fusion in a star.

Nebulae

Interstellar regions filled with gas and dust where stars are born.

Hertzsprung-Russell diagram

A graph that shows the relationship between the surface temperature and absolute magnitude (luminosity) of a star.

Galaxies

Massive groups of stars, gas, dust, and other matter bound together by gravity.

Light year

The distance that light travels in one year, approximately 9.46 trillion kilometers.

Astronomical Unit

The average distance between the Earth and the Sun, approximately 150 million kilometers.

Parsec

A unit of distance equal to 3.26 light years.

Spiral galaxy

A type of galaxy characterized by a spiral shape.

Elliptical galaxy

A type of galaxy characterized by an elliptical shape.

Irregular galaxy

A type of galaxy that does not have a defined shape.

Protoplanetary disc

A rotating disc of dense gas surrounding a young newly formed star.

Accretion

The process of matter collecting together into a bigger mass by gravity.

Fusion reactions

The process in which hydrogen atoms fuse together to create helium atoms, releasing a large amount of energy.

Gas giants

Planets mainly composed of hydrogen and helium, with a rocky core.

Comets

Chunks of ice and rock that travel through space, forming tails when they melt as they get closer to the sun.

Exoplanets

Planets that orbit other stars.

Optical Telescope

A telescope that gathers and focuses visible light from the electromagnetic spectrum.

Radio Telescope

A specialized antenna and radio receiver used to detect radio waves from astronomical radio sources in the sky.

Space Telescope

An astronomical telescope that operates in space by remote control, to avoid interference by the earth's atmosphere.

Advantages of Space Telescopes

Affordable, Easy to Use, Higher Resolution.

Disadvantages of Space Telescopes

Unusable in the day, Inconvenience to use, Cause light pollution.

Galileo

Used an optical telescope to find four moons around Jupiter and discovered the rings around Saturn.

Keck 1

Example of an effective telescope.

Keck 2

Example of an effective telescope.

Subaru (JNLT)

Example of an effective telescope.

Arecibo Observatory

Example of an effective telescope.

Proton 1

Example of an effective telescope.

Proton 2

Example of an effective telescope.

Proton 4

Example of an effective telescope.

Steady State Theory

Suggested that the universe is infinite in extent and always existed in the same form.

Big Bang Theory

The currently accepted theory for the origin of the universe.

Singularity

A single dense region from which the universe rapidly expanded.

Matter

The stuff you are made of.

Antimatter

Similar to matter but with particles having electrical charges opposite to matter.

Red Shift

What happens when light from stars moves away from us.

Edwin Hubble

Observed red shift in light coming from distant galaxies, supporting the idea of an expanding universe.

Abundance of Light Elements

The universe is about 74% hydrogen and 24% helium, supporting the Big Bang theory.

Cosmic Microwave Background Radiation

Leftover heat released after the Big Bang, now known as the cosmic microwave background radiation.

Biogeography

The study of the past and present distribution of organisms.

Comparative Anatomy

The study of features of different organisms to look for evidence of a common ancestor.

Evolution

The gradual change in characteristics of living things over time.

Homologous Structures

Parts of organisms that show evidence of a common ancestor.

Vestigial structure

A structure within an organism that has lost some or all of its function as the species has evolved.

Bonobo

The closest organism to a human, supporting the notion that they both came from a common ancestor.

Biogeography

One of the four main types of evidence that proves evolution, based on the distribution of organisms in different geographical regions.

Fossils

One of the four main types of evidence that proves evolution, the remains or traces of long-dead organisms preserved in rock.

Comparative anatomy

One of the four main types of evidence that proves evolution, the study of similarities and differences in the structures of different organisms.

Genetic evidence

One of the four main types of evidence that proves evolution, the comparison of DNA between different organisms to show common ancestry.

Homologous structures

Parts of the body that are similar or the same in different organisms, indicating a common ancestor.

DNA

Deoxyribonucleic acid, a molecule that codes for genetic instructions and contains biological information for humans and other organisms.

Human Genome Project

A project from 1990-2003 that mapped the complete DNA of humans, used to compare DNA structures and genes of organisms to prove a common ancestor.

Carbon film fossils

Fossils formed when the dead body partially decays and leaves a thin black deposit of carbon.

Fossil record

A record of all fossils found on Earth, providing evidence for evolution and showing the progression of organisms over time.

Geological time scale

A time scale showing the sequence of different fossil species found in rock layers throughout the world.

Relative dating

A method of dating fossils by comparing them to other fossils or studying the layers and ages of surrounding rock.

Absolute dating

A method of dating fossils by studying the radioactive minerals in rocks and calculating the age based on decay.

Transitional fossils

Fossils that exhibit traits common to both ancestral and derived groups, providing evidence for the evolution of new species.

Natural selection

The process where organisms that are better suited to their environment tend to survive and reproduce, passing their traits on to further generations.

Charles Darwin

The scientist who proposed the ideology of natural selection and evolution in his book "The Origin of Species".

Speciation

The process of forming new species through natural selection and adaptation.

Natural Selection

The process by which organisms with favorable traits are more likely to survive and reproduce, leading to changes in a population over time.

Pesticide Resistance

The ability of organisms, such as mosquitoes, to develop a resistance to pesticides through natural selection.

Antibiotic Resistance

The ability of bacteria to evolve and become resistant to antibiotics through natural selection.

Lamarckian Evolution

The theory that acquired traits can be passed on to offspring.

Darwinian Evolution

The theory of natural selection, where organisms with advantageous traits are more likely to survive and reproduce.

Genetic Variation

The differences in DNA sequences among individuals of the same species.

Abiotic Factors

Non-living environmental factors that affect the survival of organisms, such as sunlight, temperature, and soil quality.

Biotic Factors

Living organisms that shape their surrounding environment, such as availability of resources and presence of predators.

Population Density

The number of individuals living in a particular area, which can affect competition for resources and mating opportunities.

Habitat Destruction

The loss of natural habitats due to human activities, such as deforestation and infrastructure development.

Conservation Management

Efforts to protect and preserve species and their habitats, such as establishing national parks and reducing pollution.

Fossil Record

The history of life documented by fossils, providing evidence of past organisms and their adaptations.

Horse Fossil Record

An example of the fossil record that shows how horses adapted to changing environments through changes in teeth, eye sockets, and leg structure.