SCIENCE

syllabus point

Qualitive

uses the 5 senses to observe ( touch, smell, taste, hear, sight)- descriptive

Quanatitve

uses numbers and measurements- numerical- recorded through graphs both line and column.

observation

 Includes information that's been acquired through any of the senses.

independent

change (cause)

dependent

measure (effect)

Archimedes Principle

• He found out that the amount of water displaced = volume of a subject

• Submerged the crown in water to measure the volume & used it to determine if its density was equal to gold.

• Density = mass 

                  Volume

Alexander Flemings

• He left his petri dish containing cultural bacteria poorly sealed & went on holidays

• Once he came back he observed that mould (penecillin) had grown

• The area around the mould was free of bacteria

• He isolated the mould & tested with different bacteria & found the cause effect.

• It was Australian scientist  Howard Florey who succeeded in separating and purifying the penicillin antibiotic.

Galileo Observations:

• While viewing Jupiter through his homemade telescope, he saw what he thought were 3 fixed starts in a line through the planet

•  After a month of observations he found out that it was 4 objects and that they were orbiting jupiter

• This led to the observation that contested the traditionally cosmology idea that there was one centre of motion in the solar system.

• He soon learnt that the stars were actually the moon.

Firestick Farming

• Adapted by the Aboriginal and Torres strait island peoples.

• Firestick farming is the same as modern day back burning.

• It was used to reduce the risk of bushfires, increase the amount/ diversity of food, heat from fire, increased germination of seeds, ash used as fertilizer, fresh vegetation attracted animals, also flushed out animals, used to make paths.

Bush Medicines:

• Used by Indigenous and torres strait islander peoples included:

• Tea Tree Oil: Crushes leads and applied the paste to wounds as antiseptic, it was also used as brewing for throat ointments

• Eucalyptus Oil: Infused for body pains, fevers & chills, can also be used as an antiseptic directly on the skin.

Emu Bush: leaves were used to wash sores and cuts, occasionally being gargled, also used as antiseptic.

Random Errors

• Reduces the reliability

• Will shift each from its try value by a random amount or direction

• They can be eliminated or reduced through repetition and averaging

Systematic Errors

• Reduces the accuracy

• Shift measurements from their true value by the same amount & same direction all the time

• Usually aries from the equipment, to eliminate them use calibrated equipment to eliminate any zero or parallax errors.

PH scale

Inference

Is the conclusion you arrive at based on evidence

Wonky Holes

• One way the underground water ( fresh water) flows into the ocean

• They are high nutrients & therefore home to rich areas of fish & supplies them with food & fresh water

• Submarine freshwater springs found along the great barrier reef

• Attract large numbers of fish & are throughout to act as nursery

Collision theory

• Chemical reactions can only take place when the reacting particles collide with each others

• The collisions must have sufficient energy

• Role of chemical reaction is determined by the frequency of successful collisions

• Particles in solution can only react with particles on the surface of the solid

• The rate of a reaction increases when we increase the surface area of a solid.

Surface area to volume ratio

• Smaller sized blocks of solid reactant have a greater surface area to volume ration than larger blocks

• Therefore they have more particles on the surface so there are more collisions per second

• This increases the rate of reaction

Why are secondary resources important in primary investigations?

• Scientific investigations require support

• Allows scientists to build on knowledge

• Can direct future investigations

• Prevents research that has already been completed from being repeated

Cave formations & chemical reactions:

• Limestone caves form from erosion due to carbon dioxide in water

• Caves form in limestone (calcium carbonate) & occasionally in dolomite (calcium magnesium carbonate), when water containing dissolved carbon dioxide seeps into rock crevices & joints

Secondary sources data can be used after a primary investigation to:

1. Validate & check if your original explantation is correct

2.  To see if our explanation is relevant in the investigation

3. To gain a deeper understanding of what scientific principles are at work

4. To open up new areas of interest, new question, future investigations

5. Apply & see relevance to other areas of life  & science

Making inferences

• All scientific investigations require evidence to support their findings

• Scientists can challenge the reasoning underpinning the inferences drawn from observations in previous studies and go on to test them

• This has the potential to establish an alternative of the evidence and overturn flawed conclusions

Develop inquiry questions

By other scientists & find gaps in the research where questions have not been fully answered to

Construct suitable hypotheses:

• Developed by making a proposition about how the independent variable and the dependent variable relate to one another (cause & effect).

• By reviewing the research a scientist can determine which variable and their relations to other variables have been tested in the past, how these variables may relate to a potential inquiry question and which variable may not have been tested.

Reasons to consult research:

1.  To learn from the research methods of other scientists to improve validity, & reliability

2. To avoid unnecessary investigations by seeing what investigations have been conducted in the past

3. To make inferences from the research by learning from the work of other scientists

4. To develop inquiry questions by determining which questions have been answered & which haven't

5. To construct hypotheses to test variables that may have been identified in the research

Fractals in nature:

•  made by a simple repeating process that can produce shapes of infinite complexity eg/ pyramids

• useful in modelling structures & identifying patterns in some phenomena that appear irregular

Fibonacci sequences (irregular):

• Is a sequence of numbers that goes 1,1,2,3,5,8,13,21…

• Each number is the sum of the two numbers before it

• Some plants exhibit the pattern like branches of trees, succulents and spider webs

The aurora australis (irregular):

• Light emitted when the upper atmosphere is hit by energetic charged particles, especially electrons from the solar wind, which travel along the earth's magnetic field lines.

• When these electrons collide with oxygen and nitrogen, the gases emit light, producing mainly greens, red and violet colours

type 1 error

when a hypothesis is incorrectly accepted

type 2 error

when a hypothesis is incorrectly not accepted

Paradolia

• The tendency to interpret a vague stimulus as something known to the observer eg/ seeing faces in objects or patterns

• Cognitive processes are activated by the face life object which alerts the observer to both the emotional state & identity of the object before the conscious mind processes the information

Optical Illusion:

• We have evolved to recognise patterns, often our brains cannot help but we see things that aren't there, even if we’re aware of them

• They are a result of our brain taking ‘shortcuts’ in order to interpret information quickly

Regression analysis

 statistical process of establishing the relationship between variables

Data outlier

data point distant from other observation & measurements that may indicate an error

correlation

refers to how closely related two sets of data are (variables)

Inverse correlation

 opposite ion directing, means there is an inverse relationship between two variables

Regression analysis (r)

is a statistical analysis of the relationship between two variables

Correlation coefficient

 the strength of the correlation, is described using an r value between -1 to 1

Miasma

The Miasma theory was the belief that diseases  were caused by “bad air or noxious vapour”.

Francesco Redi

•  (1626-1697) was an Italian Physician whose work contributed significantly to disproving Aristotle's spontaneous generation theory.

•  In 1668, Redi performed one of the first  experiments to falsify the concept  that maggots spontaneously generate on meat that was left out in open air. 

John Snow

• During the Cholera outbreak in 1854  John Snow discovered another way to disprove the spontaneous generation theory through the discovery that diseases were transmitted through sewage contaminated water, rather than through miasma.

• After this observation, Snow removed the handle of the water pump leading to the contaminated water, therefore forcing the individuals in the area to find water from a less contaminated source.

Louis Pasteur

• Louis Pasteur’s work involving the swan neck experiment in 1862 was one of the most pivotal contributions to disproving the spontaneous generation theory as it helped introduce the germ theory through scientific evidence. 

•  He designed the necks of the flasks like this to allow air inside the flasks to be exchanged from the air outside, but it prevents the introduction of any bacterial particles that could find its way to the sterile liquid, as they would get stuck inside the bend of the flask's neck. 

Robert Koch

•  a German physician and microbiologist, discovered through experiments that certain microbes are the cause of specific diseases. 

• In 1884, Koch isolated the cholera-causing bacterium, where he developed a technique to grow the pure culture and proved that a specific bacterium directly caused disease. 

Phlogistion theory: origional assumption

• Phlogiston would be released & absorbed in the air, setting the object on fire

• Need of oxygen for combustion as the fuel required to keep a flame burning believed to be the phlogiston, was constantly being released

Scientist that debunked Phlogistion assumption

He studied the gain or loss of weight when tin, lead, phosphorus, & sulfur underwent reactions of oxidation or reduction. He noticed that the heated metal increased in weight which opposed the belief that the mass of the metal should decrease in the form of released phlogiston.

Radioactivity

• Also known as radioactive decay or nuclear decay, is the process by which an unstable atom emits radiation

• There are 3 types → alpha,beta & gamma

• People to be included:

• Dalton

• X-rays → Wilhelm Conrad Roentgen

• Rutherford (1899)

• Barquel

• Marie Currie

origoinal assumption for atmospheric pollution

Greenhouse gases from human activities are not the most significant driver of observed climate change since the mid 20th century

scientist who debunked atmoshperic pollution

Called it Hiatus Dr Richard Millar of Oxford university, said this update on earlier estimates suggested that “we have a little more breathing space then previously thought & we can meet ambitious Paris climate change agreement goal to limit global temperatures rise to 1.5C by 2100 ( but only if the country stops using coal”

Generalisation

• Taking something specific & applying it more broadly 

• Taking 1 or more facts & making a broader, more universal statement

assumptions

• Something you assume to be the case without proof

• Is a thing that's accepted as true and certain to happen without proof

correlations

• Process of establishments a relationship between two or more things

peer

a person who works either directly or  indirectly with you

collaboration

has a number of benefits over competition or working alone when trying to find the answer to inquiry questions that otherwise would have been next to impossible to answer. Formed as a result of the shared goals of the scientists involved

benefits of collaboration

• Increased efficiency

• Cross-discipline research

• International research

• Developed capacity of young scientist

• Crosschecking & alternative perspectives

• Reduces bias & errors

steps in peer review

1. Scientist study something

2. Scientists write article about their results

3. Journal editor receives an article & sends it out for peer review

4. Peer review reads the articles and provide feedback for the editor

5. If an article finally meets editorial & peer standards its published in a journal

benefits of collaboration

• Decreasing effects of bias

• More money involved

• A range of expertise

• Larger studies

scientific consensus

the collective judgement positions & opinions of the community of scientists in a field od study through peer review, communication & debates

Limitations of understanding

1. Development of technology

2. Lack of historical records

3. Financial support

atmoic element

• The periodic table includes 118 elements

• The periodic table is set out according to 

- atomic mass

- Periods (rows)

- Groups (columns)

Richard feynmaium

• a noble price winning physicist who worked in quantum physics, proposing that neutral atoms cannot exist beyond element 137

• His prediction is based on mathematical calculations & the Bohr election orbital model of the atom, which describes the nucleus of an atom having substantial size, yet the number of possible elements is still unknown.

Hubble constant

expanding universe, the further something is away from you, the faster its receding. Using new generational instruments like the Hubble telescope, astronomers have since reduced any uncertainty in the Hubble constant, preceding a more accurate value.

ATSI & BIAS

The biases & assumptions of the European settlers that saw indigenous societies as inferior due to an apparent lack of science, economy & organised religion, or at least one that they could easily recognise. The result was the ATSI peoples were dismissed as nomadic hunter-gatherers & considered a part of flora & fauna, rather than humans with a rich culture that practised advanced agriculture & land management techniques over tens of thousands of years

Cultural bias

• Every culture has differences in the way they perceive, do things & understand the natural world

• European culture tends to have the most scientists, therefore a cultural bias has been created leading other perspectives or methods from different cultures to be ignored or overlooked.

European bias against Aboriginals

• Europeans had little regard for the intelligence, or ability of indigenous societies to maintain complex agricultural or sustainable practices. It's only recently that we have understood & appreciated these:

1. Recycling harvest waste → compost

2. Controlled burning → firestick farming

3. Using plants for medicable purposes 

4. Harvesting grain & yams

scientific models

developed to help people understand scientific concpets & represent them in a visual medium. They are used to make predictions & may include physical & digital models. Models can be refined overtime by the inclusion of new scientific knowledge

Advantages of scientific models

• Useful for large or small things (cells, solar system)

• Very intricate & complex concepts

• Processes or occurrences that happen very slowly or very quickly (evolutions)

• Making predictions based on past & present information (climate change)

• They are constantly evaluated for accuracy by the scientific community by using peer reviews (collaborations)

Limitations of scientific models

Simplified missing details Most models cant incorporate all the details of complex natural phenomena Most models are approximations- include some approximations as a convenient way to describe something that happens in nature & not exact Trade offers- to make it as simple as possible (missing components) Only as good as the information put into them

Types of model: Diagrams

1.  are the most basic of scientific models, they’re visual representations of our understanding, they can vary in their complexity due to detail (3D/2D), whether they’re scaled or labelled EG/ Nohr model of an atom, plant/animal cell.

• They are easy to understand, show structure & relationships, quick to communicate ideas. 

• Although they AREN’T to scale &  cannot show details

Types of models: Physical Replicas

1. used to represent the very large or very small. Models can be scaled to show relative sizes. The models can also be created so that they function in a way that mimics a real process EG/ DNA structure, body

• They can be touched & manipulated, help visualise 3D objects, good for demonstrations.

• Although, they might NOT be to scale, expensive, time consuming & may oversimplify

Types of models: Analogies

1. used to make comparisons between a familiar idea with a less familiar idea. Science uses analogies to simplify more difficult concepts & build an understanding by connecting it to an already established idea EG/ water pump representing electrical system

• Makes complex ideas easy to understand by comparing them with similar things

• Although they AREN'T always exact & leads to misconceptions

Types of models: Mathematical

1. used to represent an idea or phenomena. We can use equations to determine the likelihood of an event occurring or as a way to measure a relationship between two variable EG F=ma, population growth

• They have accurate predictions, analyse patterns, tests variables, handles large amounts of data

• Although it DEPENDS on accurate data & assumptions, may not include real world factors,

Type of model: computer simulations

1.  the increase in the processing power of computers has allowed us to calculate more complex scenarios, improving the reliability of our models. Consider situations where there are many variables to play & require large amounts of calculations which modern computers are able to be more effective EG/ Climate & weather forecasts

• They stimulate dangerous or expensive situations, process data quickly, easily changed

• Although it DEPENDS on the programing data which may not represent reality

endemic

a disease that is generally found among particular people or in a certain area eg/ malaria

epidemic

a widespread occurrence of an infectious disease in a community at a particular time eg/ black plague, small pox  NOT WORLD WIDE

Pandemic

an infections disease that is found worldwide eg/ covid

SIR MODEL

is a mathematical model of epidemics.

S in SIR model?

 susceptible. The number of people who aren't infected, although they aren't immune to it.

I in SIR model?

infected or infectious. People that are infected with the disease & can transmit the disease to susceptible people.

R in SIR model?

recover. People who have recovered from the disease & are immune, so they ant be infected with the disease

Big Bang theory

• Is the most accepted theory for the origion & evolution of the universe

• In the beginning the universe was thought to have been concentrated into a single point of immense energy. An explosion within the first split second converted some of this energy to the simplest form of matter particles such as quarks which are the building blocks of protons & neutrons.

Evdience for Big Bang: Doppler effect

evidence that the universe is expanding is based on measuring the movement of the stars & galaxies away from the earth using the (fib). Changing pitch is sound waves & can be seen in light as well. 

Evidence for the Big Bange: Red shift

the black lines or missing colours in the spectra of stars are shifted from their expected position. A shift to the lower or red frequencies is called a red shift & results from a star movement away from the earth

Evidence 2 for Big Bange

the abundance of hydrogen & helium

Evidence 3 for Big Bang

cosmic background radiation. Engineers are trying to track communication satellites picking up on a consistent radio noise they can't get rid of. It was the microwave background radiation. It was the discovery of this that put an end to the steady state theory.

Steady State theory

 That the universe has always existed & that the universe is expanding & constantly creating matter as the universe expands

Geocentric model

The Sun, Moon, planets and stars orbit Earth. Proposed by Aristotle

Heliocentric model

The planets (including Earth) orbit the Sun. The Moon orbits Earth. Proposed by Galileo

Democritus

first proposed the idea that everything is made up of atoms. Since the first proposals, scientists have developed a series of more accurate & detailed models to help understand the nature & predict the behaviour of atoms & matter.

Bohr model of an atom

applied mathematics & physics principles to chemistry, influencing Rutherford's experiment & developing the Bohr model of the atom. This model, supported by physics experiments & theoretical explanations, is considered accurate & still studied in chemistry today.

development of climate models

• Climate is the average weather & climate models are the basis of how the global climate model works.

• There is always some uncertainty in models but their reliability can be tested against real data

• Using models to understand humans impacts: current climate models stand up to testing against past data well & strongly suggest that human-caused greenhouse gas emissions are causing the increased warming we are seeing

climate models

• Developments in climate change understanding including Tydal’s greenhouse effect proposal in 1861 & advanced computer models have enabled refining of climate change predictions

• Global coding was considered a possible issue in the future, two different models with two different out comes: → global coding & global warming

greenhouse effect

CO2 is absorbed infr-red heat (radiation) into the atmosphere which is known as the greenhouse effect

Evidence that helps refine/update climate models:

• Spectrograph →  used to demonstrate absorption of infa-red heat into the atmosphere by CO2

• Isotope analysis →  CO2 released from fossil fuels; increased atmospheric levels

• Deep- sea core → showed shorted cycles in global climates, suggesting the climate is more responsive to small challenges in atmospheric composition,

Advantages of SIMPLE models

• They convey very specific information without any illusion to being representations of the real world meaning that people typically understand when they have limited predictive capacity 

• They’re usually quicker to build, easier to implement, easier to interpret & to update

• Application of the model is generally very easy

• Increased level of transparency → can easily find where they go wrong

Limitations of SIMPLE models

• Very limited in capacity to predict the real world

• Trade off between generality, precision & realism

Advantages of COMPLEX models

• The predictive capabilities of complex models allow for the easy prototyping of structures & systems without the expenses of constructing & trailing something in the real world. EG/ when designing a new aeroplane, complex models allow for virtual prototyping of hundreds of designs before going to the expense of building it in the real world.

Limitations of COMPLEX models

• The algorithms used to build the model can be subject to unknown or unrecognised sources of bias, & people may assume it is truly representative of the real world when it may not be

• Reduction in clarity → it’s not easy to ask simple questions of these models, a lot of variables must be included to get an answer & peripheral variables could be having more influence than necessary

• They are costly to build, interpret, & implement in both time, money & computing power.

Model of scientific concept

1. Before constructing a model you should understand the concept you are modelling to develop an accurate & effective model (background research)

2. Planning your research/ mindmap

3. Appropriate representation: need to think about the types of model that will best facilitate the purpose of the model. Consider the audience

4. Demonstrate a prediction → a useful model has predictive power: for a complex climate model this means considering variables & being able to adapt to changes in data. For a simpler model like a physical model of the respiratory system, this may mean being able to see what happens with different gases or what happens if a lung is punctured

5. Feedback strategies: scientists give each other feedback through PEER REVIEW. This allows us to improve our ideas

6. Example → physical model & analogy model of the respritory system

respiratory system model

Concept → the respiratory system & how the lungs expand & contract

Benefits → allows students to visualise & interpret with the model. Can adjust variables to make predictions. Can be made to scale to give a sense of size

Limitations → can’t show microscopic structures. Time consuming. NOT 100% ACCURATE