Physics Chapter on Energy and Magnetism

Magnetism

• Iron, cobalt, nickel and other rare earth metals have magnetic properties
• Magnetic forces work in the magnetic field
• North attracts to south
• Mass is a measure of matter (kg)
• Weight is a measure of force (N)

Energy

• Energy is the ability to cause change or do work, measured in Joules (j) or kilojoules (kJ)
• Types of energy include heat, electromagnetic, electrical, sound, kinetic, potential, chemical, mechanical, magnetic and many more forms of energy
• Kinetic energy is the energy of motion, and depends on the speed and mass of the object.
• Potential energy is stored energy, which has the potential to cause change

Heat Energy

• Heat energy is transferred by conduction, convection and radiation
• Conduction: Transferring heat between objects through collision into neighbouring molecules and atoms
• Convection: The movement of particles through a substance, transporting their heat energy from hotter areas to cooler areas
• Radiation: Travels as a wave from a heated surface in all directions

Electrical Energy

• Electrical charges can be caused between friction between two surfaces that do not conduct electricity
• Electrical charges are also caused by the addition or removal of electrons
• Charges can be either positive (lose electrons) or negative (gain electrons)
• Charges can exert a moving force
• Charges repel each other when they have the same charge, and attract when the charges are opposite

Classification

• Classification is an organisation system
• Things are alive if they can respire, grow, excrete, move, reproduce, respond and assimilate
• Classification for living things: Kingdom -> Phylum -> Class -> Order -> Family -> Genus -> Species

Cells

• Cells are the smallest unit that can live on its own and that makes up all living organisms and the tissues of the body
• Organelle Functions:
  • Cell wall: Keeps structure and protection
  • Cell membrane: Holds cell together but allows movement of nutrients and waste through tiny holes
  • Chloroplasts: Contain green pigment called chlorophyll which absorbs light for photosynthesis and converts it to energy
  • Nucleus: Contains DNA and controls the cell
  • Vacuole: Storage space for various substances

Micro-organisms

• Very small organisms only seen through a microscope
• There are 5 groups: bacteria, fungi, protozoans, algae and viruses

Plants

• Plants are eukaryotes (large and complex cells, nucleus and organelles)
• Plants have cell walls to keep the plants structure stable
• Plants have chloroplasts which produce chlorophyll which convert the sun's energy into food
• Chlorophyll gives the plant its green colour
• Plants cells have a cell wall, cell membrane, vacuole, chloroplast, nucleus and cytoplasm

Animals

• Animals are eukaryotes (large and complex cells, nucleus and organelles)
• They do not have a cell wall
• They are multicellular
• Animal cells have cell membrane, small vacuole, nucleus, cytoplasm, ribosomes, mitochondria

Cellular Respiration

• Cellular respiration is almost the opposite to photosynthesis
• Photosynthesis: water + carbon dioxide + sun’s energy = food (glucose) + oxygen
• Respiration is the process that releases this energy
• Every cell needs energy to keep functions
• The respiratory system, along with the digestive system and circulatory system, carry oxygen and air to each cell
• Respiration: glucose + oxygen = carbon dioxide + sun’s energy + water

Body Systems

• Complex multicellular organisms such as humans have several body systems and specialised organs
• Some examples of body systems include the respiratory system, excretory system, digestive system, reproductive system and many more.
• Cells -> tissues -> organs -> organ systems -> organism

Digestive System

• The digestive system works by breaking down food into nutrients
• Food is broken down physically through chewing the food and using stomach muscles to churn around the food.
• Food is broken down chemically using the enzymes in the stomach
• Food passes through the oesophagus and the nutrients are broken down
• The circulatory system then transports all the nutrients which get absorbed into the bloodstream through the capillaries in the small intestine

Circulatory System

• The circulatory system transports oxygen and nutrients, and removes waste
• Main components: heart, blood vessels, blood
• Heart:
  • Separated into 2 sides by the septum
  • Right side pumps deoxygenated blood to the lungs
  • Lungs oxygenate blood and returns it back to the left side where it gets pumped around
• Each side of the heart is divided into the atrium and ventricle, separated by valves
• Blood vessels: Arteries...