8th Grade Science Lecture Notes

Comprehensive vocabulary flashcards covering the 8th-grade science curriculum including seasons, genetics, pressure, matter, simple machines, and energy cycles.

Geoid

The shape of the Earth, which is flattened at the poles and bulging at the equator.

Solstice (Gün Dönümü)

The dates (June 21 and December 21) when the sun's rays arrive perpendicularly to the tropics, marking the longest day or night.

Equinox (Ekinoks)

The dates (March 21 and September 23) when day and night are equal in length (12 hours each) and sun rays fall perpendicularly on the equator.

Climate (İklim)

The average of weather events observed in a specific region over a long period (30-35 years).

Meteorology

The branch of science that examines weather events and their effects on living things and the environment.

Low Pressure Area (Alçak Basınç)

An area with low air density where upward air movement occurs, often associated with warm air and clouds.

Wind (Rüzgar)

Air movement occurring in a horizontal direction from a high-pressure area to a low-pressure area.

Humidity (Nem)

The water vapor present in the air, measured with a hygrometer (nemölçer).

Precipitation (Yağış)

Atmospheric water vapor that falls to the ground in forms such as rain, snow, hail, dew, frost, or fog.

DNA (Deoxyribonucleic Acid)

The manager molecule of the cell that carries hereditary information and controls vital activities like respiration and reproduction.

Nucleotide

The building block of DNA, consisting of a phosphate, a deoxyribose sugar, and a nitrogenous organic base.

Gene

The functional unit of DNA that carries instructions for specific hereditary traits like hair color or eye color.

Chromosome

The X-shaped hereditary structure formed when DNA is wrapped in special proteins during cell division.

Mutation

Sudden, permanent changes in the structure of DNA caused by factors like radiation, chemicals, or extreme heat.

Modification

Non-hereditary changes in the functioning of genes due to environmental factors like temperature, light, or nutrition.

Adaptation

The hereditary ability of a living thing to adjust to its environment to increase its chances of survival and reproduction.

Natural Selection (Doğal Seçilim)

The process by which organisms better adapted to their environment tend to survive and produce more offspring.

Biotechnology

The technology used to modify living structures to produce useful products for human needs or industrial use.

Pressure (Basınç)

The perpendicular force acting on a unit surface, calculated as $\text{Pressure} = \frac{\text{Force}}{\text{Area}}$.

Pascal Principle

The rule stating that liquids are incompressible and transmit applied pressure equally in all directions.

Open Air Pressure (Açık Hava Basıncı)

The pressure exerted by the atmosphere's weight, measured by Torricelli as $760\text{ mmHg}$ at sea level and $0^\text{ oC}$.

Periodic System

The table where elements are arranged according to their increasing atomic numbers (proton numbers).

Metalloids (Yarı Metaller)

Elements like Boron ($B$) and Silicon ($Si$) that have physical properties of metals and chemical properties of non-metals.

Physical Change

A change in the external appearance of a substance without altering its chemical identity, such as state changes or dissolving.

Chemical Reaction

A process where substances undergo chemical changes to form new substances by breaking and forming chemical bonds.

Acid

A substance that produces hydrogen ions ($H^+$) in water, has a sour taste, and a pH value between $0$ and $7$.

Base

A substance that produces hydroxide ions ($OH^-$) in water, has a bitter taste, and a pH value between $7$ and $14$.

PH Scale

A scale from $0$ to $14$ used to measure the acidity or alkalinity of a solution.

Specific Heat (Öz Isı)

The amount of heat required to change the temperature of $1\text{ g}$ of a pure substance by $1^\text{ oC}$, denoted by the symbol "$c$".

Latent Heat of Fusion ($L_e$)

The heat required to change $1\text{ g}$ of a solid substance at its melting point into a liquid state.

Simple Machine

Tools consisting of few parts and using a single type of force to make work easier by changing force magnitude or direction.

Fixed Pulley (Sabit Makara)

A pulley that is attached to a fixed point; it does not provide force advantage but changes the direction of the force.

Movable Pulley (Hareketli Makara)

A pulley that moves with the load, providing a two-fold force advantage ($\text{Force} = \frac{\text{Load}}{2}$).

Lever (Kaldıraç)

A simple machine consisting of a rigid bar that rotates around a fixed point called a fulcrum.

Inclined Plane (Eğik Düzlem)

A sloping surface used to lift heavy loads with less force, where force advantage increases as slope decreases.

Wheel and Axle (Çıkrık)

A simple machine consisting of two cylinders with different radii that rotate around the same axis.

Food Chain

The sequence of transfers of energy in the form of food from one organism to another.

Photosynthesis

The process by which producers use light, water, and carbon dioxide to produce glucose ($C_6H_{12}O_6$) and oxygen ($O_2$).

Aerobic Respiration

The process of breaking down food using oxygen to produce a high amount of energy ($38\text{ ATP}$) in the mitochondria.

Anaerobic Respiration (Fermentation)

The process of breaking down food without oxygen to produce energy ($2\text{ ATP}$) and products like lactic acid or ethyl alcohol.

Nitrogen Cycle

The circulation of nitrogen from the atmosphere through lightning and bacteria into the soil and living things, and back to the air.

Sustainable Development

Planning the conscious use of natural resources without damaging them for the benefit of future generations.

Electroscope

A device used to detect whether an object is electrically charged and what type of charge it carries.

Grounding (Topraklama)

Connecting an electrically charged body to the Earth with a conductive wire to make it neutral ($0\text{ charge}$).

Generator (Jeneratör)

A device that converts mechanical (motion) energy into electrical energy.