Science Notes - Sem 2 2024

Undernourished

Having insufficient food or other substances for good health and condition.

Countries in need of food

Countries such as Zimbabwe, Zambia, Central African Republic, Kenya, and Nigeria.

Main causes of hunger

Conflict, Climate Change, Economy, Gender inequality, Food waste, Extreme weather.

Ways to reduce food waste

Only buy what is needed, Put food waste to use (e.g. compost), Support local food providers, Store food wisely, Share uneaten food.

Simple Carbohydrates

Primary source of energy; examples include glucose, sugary lollies, sugar, ice cream, fruits, and honey.

Complex Carbohydrates

Provide more lasting energy; examples include bread, wraps, rice, and oats.

Fats and Oils

Examples include olive oil, coconut oil, and butter.

Proteins

Regulate the body’s tissues and organs; examples are eggs, meat, and yogurt.

Vitamins

Essential nutrients, examples include Vitamin C tablets, oranges, and carrots.

Minerals

Inorganic nutrients, examples include iron and charcoal.

Common characteristics of metals

Lustre, conductive, malleable, solid, ductile.

Common characteristics of non-metals

Brittle, not malleable, not conductive, gaseous, not ductile.

Roots

Structure with xylem and phloem that stabilizes the plant and absorbs water and salts.

Xylem

Moves water to the leaves (only up).

Phloem

Transports glucose up and down the leaves.

Stems

Transport nutrients; holds flowers and leaves.

Leaves

Contain stomata for gas exchange in photosynthesis.

Photosynthesis

Process used by plants to produce glucose, requiring light and carbon dioxide.

Respiration

Conversion of glucose into energy.

Conservation of Energy law

Energy cannot be created or destroyed, only transformed.

Roller Coaster Dynamics

Roller coasters convert potential energy into kinetic energy.

Weight

Mass multiplied by gravity (Weight = Mass x Gravity).

Net Force

Result of subtracting opposing forces; add forces in the same direction.

Unbalanced Forces

One side applies more force than the other, causing movement; net force is not 0 newtons.

Balanced Forces

Forces that cancel each other out; net force is 0 newtons.

Friction

A force resisting motion between two surfaces in contact.

Reducing Friction

Using lubricants, streamlining objects, and using rollers or ball bearings.

Types of charges

Protons (positive), Neutrons (neutral), Electrons (negative).

Measuring Force

Force is measured in newtons using a force meter or spring balance.

Air Resistance

A form of friction that increases with an object's speed.

Terminal Velocity

The constant speed when weight force and air resistance are balanced.

Triage

Assessing the severity of an injury to determine treatment order.

Unicellular organisms

Organisms consisting of one type of cell, producing identical copies through mitosis.

Multicellular organisms

Organisms consisting of multiple cell types, with mitosis for growth and repair.

Components of the circulatory system

Heart, blood vessels, and blood, all work together to deliver nutrients and oxygen.

Function of the heart

Keeps blood mobile, providing cells with oxygen and nutrients.

Arteries

Thick-walled vessels that pump oxygenated blood away from the heart.

Veins

Similar to arteries but with thinner walls and one-way valves directing blood to the heart.

Capillaries

Thinnest blood vessels, one cell thick, connecting arteries and veins.

Natural pacemaker

Sinoatrial node controls the heart's rhythm by sending electrical signals.

What are sound waves?

Waves created through object vibration that are not visible to the human eye.

What are light waves?

Forms of moving energy made of particles called photons.

What is kinetic energy?

Energy of a moving object.

What is gravitational force?

Force keeping objects bound to the Earth.

What is electrostatic force?

The force between electrically charged objects.

Compliance

Ability to adapt and respond to pressure or stress.

Gravity ratios

Comparison of gravitational force on different planets.

Mitosis

Cell division that results in two identical daughter cells.

Photosynthesis Word Equation

Carbon dioxide + Water + Light energy → Glucose + Oxygen.

Chemical energy

Energy stored in the bonds of chemical compounds.

Kinetic energy formula

KE = ½ x mass x velocity squared.

Gravitational potential energy formula

GPE = Mass x Gravity x Height.

Specific heat capacity

Amount of heat needed to raise the temperature of a unit mass of a substance by one degree Celsius.

Nutrient transport

Process by which nutrients and oxygen are delivered to cells in the body.

Pollination

Process by which pollen is transferred to fertilize plants.

Oxygen transportation

Oxygen is carried by red blood cells and dissolved in plasma.

What is thermal energy?

Internal energy present in a system due to its temperature.

What is the function of the sinoatrial node?

Controls heart rhythm by sending electrical signals.

What role do capillaries play?

Connect arteries and veins and facilitate substance exchange.

What is the fluid part of blood?

Plasma that carries dissolved nutrients, hormones, and waste.

What are blood cells?

The solid part of blood that includes red blood cells, white blood cells, and platelets.

What is heat in physics?

A form of energy that transfers between a system and its surroundings.

What is sound in physics?

Vibration that travels through air, water, or solid materials.