Investigating Science Year 11 Prelims

Observation

Observation refers to noting or recording a result, occurrence, or phenomenon. Information that has been acquired through any of the senses including sight, hearing, taste, feeling and smell

What do observations allow us to do?

Invent new tools, discover natural laws and explore the mysteries of the universe

Direct observation

Uses our senses e.g. using our eyes to see the stars

Indirect observation

Uses tools, like thermometers or microscopes e.g. using a telescope to view the sky in detail

What is the role of observations in science?

• Collect and record data

• Construct hypotheses

• Test hypotheses (experimentation)

• Make conclusions

• Produce theories

How are observations useful in investigations?

• Can instigate scientific inquiry by providing researchers with a starting point

• Can provide a means of gathering data

• Can be used as evidence to investigate a hypothesis

What do observations lead to?

1. Collecting data

2. Making inferences

What are the types of data?

1. Qualitative observations (Descriptive)

2. Quantitative observations (Numerical)

What are the quantitative and qualitative observations of burning a candle?

Qualitative observation: Candle slowly extinguishes and water level rises and eventually stops

Quantitative observation: Time taken for candle to extinguish, final water level

Inferences

Use information or data to make conclusions to suggest a reason why we observe something.

Based on this observation: A specific bird species always builds its nest in a particular type of tree. What inference can be made?

The bird prefers that tree because it provides a suitable habitat for raising young.

What inferences can be drawn from burning a candle?

1. With no flame, the temperature and pressure inside the container decreases

2. The pressure inside and outside the container tries to equalise, forming a vacuum.

3. A vacuum is caused by the loss of heat from the candle being out.

4. The water is sucked up into the container until the pressure is balanced.

What are the quantitative and qualitative observations of Rock Strata?

Qualitative observations: Texture, colour, layering of pattern

Quantitative observations: Layer thickness, dip angles

What inferences can be drawn from Rock Strata?

By examining the order, composition, and fossil content of Rock Strata layers, geologists can infer past environments, geological events, and the evolution of life.

Bernoulli Effect

Bernoulli’s principle describes the relationship between fluid (liquid or gas) speed and pressure: faster-moving fluids have lower pressure, and slower-moving fluids have higher pressure.

What are the quantitative and qualitative observations of the Bernoulli Effect?

Quantitative observations: Measurable decreases in fluid pressure as fluid velocity increases.

Qualitative observations: Effects like a stream of air pulling nearby objects together or a shower curtain moving inward when water flows, showing that faster-moving fluid creates lower pressure.

King Hiero’s Crown

1. King Hiero commissioned a royal crown with a local goldsmith

2. The goldsmith returned the finished product, but King Hiero was suspicious of the goldsmith.

3. He wondered if the goldsmith had only used some of the gold he had given him and filled the rest of the crown with silver, keeping the extra gold for himself.

4. King Hiero then hired Archimedes to investigate and determine whether his suspicions were correct.

Density

Measure of how much “stuff” is packed into the volume of an object. P = m/v

Archimedes’ experiment

1. Archimedes experimented with this process by having replicas of the crown made: one made of pure silver and the other of pure gold. Both replica crowns had the same weight but different sizes.

2. Archimedes put the silver crown in the water, and collected and measured the volume of the water that overflowed. Then, he repeated the process with the golden crown.

3. As the silver crown was larger (because its density was lower), it displaced more water as it had a larger volume.

4. Then, testing King Hiero's crown, Archimedes saw it displaced more water than the replica golden crown. This meant that it had a larger volume, and indicated that it was not made purely of gold.

Fleming’s experiment

1. Fleming left a petri dish with bacteria next to an open window for a few weeks

2. When he next checked the bacteria-filled dish it had been contaminated with mould and the mould was ‘eating away’ at the bacteria

3. Fleming identified the substance in the mould responsible for killing the bacteria and named it penicillin.

Galileo observing Jupiter’s Moons observation and inference

Observed that moons were orbiting around Jupiter

Inference: Planets orbit the sun

Geocentric Model

Earth is the centre of the universe

Heliocentric model

Planets orbit the sun

Phases of Venus

• Galileo observed that the phases of Venus were similar to the phases of our moon

• Galileo inferred that both bodies must have the same light source, the sun and that the way the phases appeared meant that the geocentric model was incorrect

Jupiter’s moons

• Galileo observed how Jupiters moons followed a pattern every month

• Galileo inferred that this pattern showed that Jupiter also had other bodies orbiting it and Earth was not the only planet that had things orbiting it, disproving the geocentric model

What does observing the behaviour of plants, animals and weather help with?

Helps with determining when to hunt, fish and gather

What does observing changes in animal migration patterns, breeding habits and feeding behaviour help with?

Informs conservation strategies

Firestick farming

A land management technique that uses fire to manage the landscape.

Describe an example of a way in which Aboriginal and Torres Strait Islander Peoples have used observation and inference to develop an understanding of Country and Place in order to create innovative ways of managing the natural environment. (Firestick farming)

Aboriginal and Torres Strait Islander peoples used fire-stick farming as a way to manage the natural environment. Through careful observation over thousands of years, they noticed that small, controlled burns using patch burning encouraged new plant growth, attracted grazing animals like kangaroos. From these observations, they made the inference that fire could be used deliberately as a land management tool. By applying this knowledge, they created a mosaic of burnt and unburnt land that maintained biodiversity, provided reliable food sources through hunting and ensured the long-term sustainability of Country.

Aboriginal people used observation to notice how naturally occurring bushfires cleared old vegetation, encouraged new plant growth, and attracted animals to graze on the fresh shoots. From this, they made the inference that if fire was used deliberately in small, controlled ways, it could be a tool for managing the land. This practice, known as firestick farming, created patchworks of burnt and unburnt areas that promoted biodiversity, made hunting easier, protected important plants, and reduced the risk of large destructive bushfires. In this way, careful observation and inference allowed Aboriginal peoples to develop an innovative and sustainable method of managing the natural environment.

Describe an example of a way in which Aboriginal and Torres Strait Islander Peoples have used observation and inference to develop an understanding of Country and Place in order to create innovative ways of managing the natural environment. (Medicinal plants)

Observations made by Aboriginal people were a vital part to the implementation and use of natural medicines and remedies within their society. This is because through these observations they allowed Indigenous people to recognise and utilize the healing and beneficial properties of plants and nature. These observations were crucial, as the necessary information gathered was passed down through generations, carrying through their traditions and culture that we now know due to their careful observations of nature, and how they survived for 60 000+ years. An example of how observations conducted by Indigenous people further leading to the development of natural medicines is seen through the properties in which they uncovered within tea tree leaves. The indigenous concluded through their observations that tea tree leaves had natural healing properties which helped relieve colds, prevent wound infections and clean up skin. These observations made by Aboriginal people amongst their day-to-day environmental interactions highlights how critically and effectively they observed and studied their surroundings in which enabled the refinement of traditional medicinal practices and laid the foundations of modern-day medicine.

Aboriginal and Torres Strait Islander Peoples closely observed the natural properties of plants like the tea tree. They noticed that when the leaves were crushed, they released oils with a strong smell and that applying these leaves to wounds or infections reduced swelling and promoted healing. From these observations, they made the inference that tea tree leaves contained medicinal properties and could be used as natural antiseptics. This understanding led to innovative environmental management practices, as tea trees were carefully harvested and used sustainably, ensuring the resource was never depleted. By combining observation with inference, they developed a sophisticated knowledge of bush medicine that not only managed human health but also reflected a deep respect for and sustainable interaction with Country.

European settlers did not always appreciate the agricultural practices of First Nations Peoples. However, these Peoples had many practices based on observations and inferences that helped them survive. Evaluate some biases that may have affected scientific thinking of European settlers regarding the agricultural practices of First Nations peoples

Racial biases:

• European settlers believed people with darker skin were ‘inferior’ and would be less likely to listen to them and so they didn’t believe in their agricultural practices

• As ATSI peoples were all black at the time, the settlers thought that their ideas (fire-stick farming, seasonal harvesting) were not as good as European ones (fencing, ploughing)

Not technological:

• European settlers were in the age of the Industrial Revolution, to them technologies were the best way to get things done and didn’t believe in traditional methods

Nomadism:

• Seasonal rotation of harvesting areas was wrongly seen as nomadism rather than a sustainable system to prevent overuse of the land and European people thought it was inferior

Eurocentric perspective:

• They had experienced their way of doing things to be highly successful in the past

• They thought that Aboriginal peoples controlled burning, management of native plants, firestick farming, natural fertilisers, rotational hunting and crop rotation were inferior and underestimated the First Nations’ peoples ecological knowledge

• They thought their own agricultural practices were advanced and efficient while First Nations peoples were primitive and backward

• Failed to understand the sophisticated land management systems of First Nations peoples

Geological Strata

• Stacked-up layers of rock in the Earth’s crust

• Layers often represent different geological periods

Qualitative and Quantitative data we can collect from Rock Strata

Qualitative: Rock type, colour, shape

Quantitative: Elevation, layer thickness, grain size

Outline 2 ways in which observations may be enhanced by using digital thermometers over analogue thermometers

• Show an exact reading of the temperature and remove possibility of human error

• Digital thermometers are more precise than analogue thermometers

What are the disadvantages of digital technology

Expensive

Discuss how observations have been limited by observation tools and how their improvement has helped develop knowledge

• Used to believe that Earth was the centre of the universe due to our lack of observational tools as we were only able to see planets as we only had the naked eye meaning our knowledge of the universe was restricted and we believed in the geocentric model

• Galileo developed his own telescope by improving the tool of the naked eye and observed the phases of Venus as being similar to our moons and this helped develop knowledge leading to the creation of the heliocentric model

• As telescopes continued to improve, later tools such as radio and space telescopes allowed scientists to observe galaxies, black holes, and cosmic background radiation, further expanding knowledge of the universe

• This shows how better observation tools overcome earlier limitations and lead to major scientific breakthroughs

Spectroscopy

Study of different wavelengths of light

How could spectroscopy be used as evidence for the Big Bang?

• Spectroscopy splits light from galaxies into a spectrum, showing characteristic absorption/emission lines

• Observations show these lines are redshifted (shifted towards the red end of the spectrum).

• Redshift indicates galaxies are moving away from us.

• This means the universe is expanding.

• If the universe is expanding now, it must have started from a much smaller, denser state.

• This provides strong evidence for the Big Bang theory.

Why is the Hubble Space Telescope superior to those on Earth and how has it benefitted astronomy?

• The Hubble Space Telescope is superior to Earth-based telescopes because it orbits above the atmosphere, avoiding distortion, weather, and light pollution, while also detecting wavelengths like ultraviolet and infrared that are blocked on Earth.

• This has led to clearer, sharper images and uninterrupted observations. Hubble has greatly advanced astronomy by helping determine the age of the universe, providing evidence for dark energy, revealing how galaxies evolve through deep-field images, and even analysing exoplanet atmospheres. Its discoveries have not only transformed scientific knowledge but also inspired global public interest in space.

Assess the impact of observation tools on scientists’ observations of the universe

• The development of observation tools has had a profound impact on scientists’ understanding of the universe. Early naked-eye observations limited knowledge to visible stars and planets, supporting incorrect models like the geocentric theory.

• With the invention of the telescope, astronomers such as Galileo were able to observe Jupiter’s moons and the phases of Venus, providing evidence for the heliocentric model.

• Later, improved telescopes, including the Hubble Space Telescope, allowed scientists to see distant galaxies, measure redshift, and refine the age and expansion rate of the universe.

• These technological advances show that as observation tools improve, they overcome earlier limitations, enabling new discoveries and significantly expanding scientific knowledge of the universe.

How can we use data to form further research questions?

• Check for any inconsistencies in our data

• Investigate unexpected results

• Analyse untested variables

Independent variable

The variable we change

Dependent variable

The variable that we measure

Controlled variables

The variables that we keep constant

Reliability

Reliability refers to how consistent data is in repeated measurements. The experiment should be undertaken at least 3 times with consistent results and an average must be calculated to ensure that the results are reliable and trustworthy.

Accuracy

Accuracy refers to whether the results are close to the "true value". So, the quality of the measuring apparatus and the skill of the scientists taking the measurement affects accuracy. If the apparatus is faulty or the scientists make a mistake, the measurement may be inaccurate.

Validity

Validity refers to how suitable the method is and if all variables are identified and controlled appropriately to the aim of the experiment.

How can you increase validity of an experiment?

1. Controlling Variables

2. Ensure that 1 variable is being changed and 1 being measured and the rest are constant

Data

Any information or facts we collect or observe during a scientific investigation

Primary data

Data collected for the first time through original research methods e.g. surveys, experiments, observations

Secondary data

Data someone has previously collected, organised, and analysed by someone else e.g. books, magazines, newspapers, government publications

What are some different data collection methods?

1. Experiments (primary)

2. Observational studies (primary)

3. Case studies (secondary)

4. Surveys (primary)

Line graphs

• Used to visualise trends over time for continuous variables

• Useful for comparing multiple trends or variables on a single graph

Scatter plot

• Used to analyse the relationship between 2 continuous variables

• Used to display the overall trend or pattern in the data in order to compare variables

Bar graph

• Used to compare categorical data like colour or blood type

How can qualitative data be represented as a visual or digital representation?

• Images

• Photos

• Diagrams

How can quantitative data be represented as a visual or digital representation?

• Tables

• Graphs

• Maps

How would you use visual and digital representations to collect data?

• Sensors

• Imaging

• 3D modelling and simulations

Draw

To reach a conclusion through deduction or inference

How to draw conclusions based on data?

Describe any trends, patterns, relationships and consider any limitations

Positive correlation

Two variables increase together

Negative correlation

One variable increases while the other decreases

Exponential increase

Variable increases at an accelerating rate (steep upward curve)

Exponential decrease

Variable decreases at an accelerating rate (steep downward curve)

Why do we assess scientific findings?

• To help validate our results

• To understand the significance of our results

• To identify new questions for further exploration

Tabulation

• Easy for results comparison

• Sometimes results table format can be difficult

• Efficient way to record quantitative data

• Purpose of a table is to allow peers to review the results of an investigation without having to decode long scientific jargon

Graphing data

Visual representation of results

Line graph vs scatter plot

Line graph: The data points are connected sequentially and the order matters e.g. Temperature over a week.

Scatter plot: You want to show the relationship/correlation between two variables e.g. Hours studied vs. test score

How to construct your table?

Writing a conclusion

You conclusion should:

• State what the results of the experiment indicate

• Link to the aim of the experiment

• Include actual values from your results to support your claim

I like to start my conclusion by writing "The results indicate..." DON'T SAY PROVE. Say support, reject

Example: The results do not support the hypothesis that as boiling time increased, voltage increased from 0.2 volts for raw to 9.6 volts for 10 minutes.

Discussion

The discussion is where the trends indicated by the results are discussed. This is also where validity, reliability, accuracy, errors and uncertainty is discussed. Each aspect is multifaceted and should be discussed in depth.

CUTLAS

Crosses

Units

Title

Label both axes

Axis

Straight line of best fit

Size

Why process toxic plants for bush tucker?

• Native plants were an essential part of Aboriginal peoples diet and nutrition

• When other food was scarce, they needed to make these foods safe to eat

How did Aboriginal peoples use toxic plants to make them edible?

• Made careful observations of plants, animals and the environment

• Led to inferences of plant edibility and processes for ridding them of toxicity

Methods used by Aboriginal people to transform inedible plants to edible staple foods (Australian Cycads)

1. Crushing the kernels are pounded into smaller pieces helping leach out the toxins

2. Soaking for several days which allows the toxins to dissolve and be carried away by the water

3. Drying in the sun to reduce moisture and prevent rotting

4. Cooking as Aboriginal people observed that cooking or heating the fruit makes it taste better, breaks down the toxins from food and no-one gets sick

Aboriginal and Torres Strait Islander Peoples used the fruit of cycad and used it as a food

source. They developed methods to remove toxins from cycads that allowed cycad seeds to

become a rich food source. Different methods were used to achieve this. Seeds were removed

from husk and then cooked and leached in running water overnight to remove the toxins.

Another method was to dry the seeds and then leached in running water for 3-5 days.

Fermentation was also used as a method to remove the toxins.

How were Aboriginal people able to locate sources of freshwater within bodies of salt water?

• Observing specific behaviours like birds soaring or gathering inland, they can infer there are nearby freshwater sources

• Different plant species thrive in freshwater and saltwater environments so they can infer there is freshwater in some areas

What are the 4 techniques used by Aboriginal people to locate freshwater?

Technique	Description
Gnammas/Rock Holes	Natural depressions in rocks that collect and store rainwater and doesn't drain away after the rain
Impoundments/Clay dams	Small dams built in clay soils to trap and store surface water after rainfall. These acted like reservoirs, holding water for use during drier times.
Tree roots	Certain trees (e.g., eucalyptus) hold fresh water in their roots. Aboriginal Peoples would dig up roots, cut them into pieces, and drain the water by squeezing or sucking.
Kappi wodern	Freshwater feeds into reefs through underground springs that come up from the water table. During low tides or days without wind, freshwater rises because it has a lower density than saltwater, and it floats on the top.

What are key qualitative methods used to collect data on water quality?

• Water colour

• Plant and animal species

What are the key quantitative methods used to collect data on water quality?

Measuring pH, temperature and dissolved oxygen

How can you use secondary sources to validate inferences and conclusions?

• You might find that other studies come to the same conclusions so your conclusion is solid + adds a level of credibility to your findings

Why gather secondary source research before planning an investigation?

1. Make informed inferences based on existing knowledge

2. Allows us to develop focused inquiry questions that address gaps in knowledge and contribute to our understanding of the topic

3. Assists us in constructing suitable hypotheses

4. Helps us plan our investigations

5. Helps us to avoid unnecessary investigations

6. Reveals limitations or errors in past research

7. May be outdated or biased or inaccurate

Why do animals migrate?

• Find more food

• Find a more suitable environment

• Raise their young in favourable conditions

How do animals migrate?

Animals are able to navigate by:

• Learning from previous generations

• Using the sun and stars

• Using the earth's magnetic fields

• Using landmarks

What is an example of an animal that migrates?

In earlier times, people believed whales “disappeared” or even died off seasonally when they vanished from local waters, because they had no way of tracking them across oceans. The assumption came from observing the pattern of absence but misinterpreting its cause. Humpback whales migrate thousands of kilometres every year. They travel from cold polar waters, where they feed in summer to warm tropical waters, where they breed and give birth in winter.

Movement of comets

• Comets are leftover materials from the formation of our solar system and orbit our sun

• They can be identified by their tail, which is ice vaporising as it gets closer to the sun

• Follow Kepler’s Laws of Planetary Motion – the closer to the sun they are, the faster they move

• They have a highly elliptical orbit

• Comets originate from the Kuiper belt or Oort cloud. Those from Kuiper are in plane with the solar system. Those from Oort are at random angles to the solar system.

Comets travel in elongated, elliptical orbits around the Sun, spending most of their time in the cold outer solar system before a gravitational disturbance sends them inward. As a comet nears the Sun, its ice heats up and turns directly into gas, forming the visible coma and tail, which are always pointed away from the Sun.

Patterns are repeated events in nature. Patterns have been observed overtime throughout the

universe that have supported scientists in constructing body of evidence required to support

scientific conclusions. Scientists seek to identify and understand patterns in our world by

drawing on their scientific knowledge to offer explanations that enable the patterns to be

predicted. One such example is Halley’s comet. Previously, comets were thought to be

unique one-time events. In 1860, English astronomer Edmond Halley became interested in

positions of the comets and started to plot the path of comets and identified a pattern of

comets that approached Earth. He used Newton’s law of gravitation and searched the

historical records to conclude that the same comet had approached Earth in 1531, 1607, 1682

and predicted its return in 1758. This comet is now called as the Halley’s comet and has an

elliptical path around Sun with orbital time of 75 years. Hence, it was established that comets

orbit the Sun and will be observed approaching the Earth periodically.

Formation and shape of crystals

• Snowflakes form around dust particles in air

• The shapes and sizes are determined by the weather

• The drier the weather conditions, the simpler the snowflake

• Due to the nature of bonding in water molecules, snowflakes are always symmetrical and 6 sided

Elements exhibiting certain properties

Mendeleev looked at increasing atomic mass and similar properties of elements to organise the periodic table we know today

Now it has been used to show many more properties such as:

• Atomic mass

• Atomic number

• Atomic radius

• Electronegativity

• Ionisation energy

A clear pattern observed in nature is the recurring properties of elements. When scientists, including Dmitri Mendeleev, studied elements, they noticed repeating trends in properties such as reactivity, conductivity, and atomic radius when the elements were arranged by increasing atomic mass. These consistent patterns over time built a strong body of evidence for Mendeleev’s scientific conclusion that elements exhibit periodic properties, which led to the development of the Periodic Table. This organisation not only explained existing patterns but also allowed Mendeleev to predict the properties of elements not yet discovered, further confirming the validity of his conclusion.

Fractals

Are repeating, infinite patterns and irregular geometric patterns that exhibit self-similarity and repeat at different scales seen throughout nature

Examples in nature:

• Vascular system in plants

• Snowflakes

• Electricity discharge

• Romanesco cauliflower

• Coastlines

• Seashells

• Galaxies

Aurora Australis

• Solar flares from the sun produce electrons that are sent towards Earth

• The Earth’s magnetic fields pull these towards the north and south pole

• Particles collide with atoms in the atmosphere – colours are produced as these atoms drop from excited states

Predicting the Aurora Australis

• Auroras follow the solar cycle = 11 years

• Years with high levels of activity tend to have more spectacular auroras

• Auroras also coincide with sunspots turned towards earth. They help with predictions as the sun takes 28 days to rotate.

• There is no precise way to accurately predict an aurora

Unstable isotopes

• An isotope is a type of atom from the same element but with a different number of neutrons

• Isotopes that are unstable release radiation and undergo nuclear decay – their ratio of protons to neutrons is too large

• All elements after lead (atomic number > 82) are unstable

Type 1 error

• Type I = hypothesis is incorrectly accepted

  • patterns aren’t there, but look like they are

  • random data looks like a pattern by chance

  • we use statistical analysis to overcome this error

Type 2 error

• Type II = hypothesis is incorrectly rejected

  • failing to recognise a pattern

  • usually happens because variables aren’t controlled

  • leads to misinterpreting patterns

Pareidolia

• The tendency to perceive a specific, often meaningful image in a random or ambiguous visual pattern

• Can be visual or auditory

• The tendency to see faces in random objects

Optical illusions

• Misleading image presented to vision

• The image processed by the brain is different to reality

• Our brain taking shortcuts to interpret information quality

Correlation vs Causation

Correlation signifies a statistical association between two variables, indicating they tend to change together, but not necessarily that one causes the other.

Causation, on the other hand, means that a change in one variable directly causes a change in the other

How can data be misinterpreted?

• Personal bias

• Poor scientific method

• Inaccurate data

• Confusing correlation for causation

• Unethical behaviour

• Sampling errors

• Quoting numbers within margin of error

• Making generalisations

• Not considering outside causes

• Deception

Outliers

• An unusual score that deviates from the rest of the data set

• It is further away from the rest of the data points and lies out of the general pattern

How do outliers affect data analysis?

Outliers can bias estimates and errors

• Affects the mean

  • Increases with a high value

  • Decreases with a low value

• Affects the slope of the data

  • The line of best fit will be skewed towards the outlier

• Increases the range and standard deviation

• Standard error of regression (R2 value)

• Affects P-value (statistical significance)

What are the advantages and disadvantages of outliers?