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Science focus 4 homework book online

The motives for his crimes remain a mystery. Fig 1. A poorly forged will led to his capture. Plasticc banknotes are m more durable than paper ones, lasting four to five times imes longer. Dr Shipman would 3 State what can be used to determine which typewriter was ansom note.

NPA also sells plastic blank notes to government printers in other countries so that they can print their own money. Understanding 6 Investigators generally ignore the slant and spacing of letters in a handwritten document. Explain why. Chapters may also include information on other Prescribed Focus Areas. The verbs in black are the key verbs that have been developed to help provide a common language and consistent meaning in the Higher School Certificate documents.

All other verbs listed below feature throughout the book and are provided here for additional support to teachers and students. Remembering Analysing List Name Present Recall Record Specify State Analyse write down phrases only without further explanation present remembered ideas, facts or experiences provide information for consideration present remembered ideas, facts or experiences store information and observations for later state in detail provide information without further explanation Understanding Account Calculate Clarify Define Describe Discuss Explain Extract Gather Modify Outline Predict Produce Propose Recount Summarise account for: state reasons for, report on.

Unit 1. These might be about how animals like ants breathe, how rainbows are formed, why sunsets are red or what affects the rate at which fruit rots. To performing experiments. An experiment is simply a test on a small part of the world. Science: Asking questions The answers to questions that scientists ask often can be found in textbooks, encyclopaedias or on the Internet.

Sometimes the questions that scientists ask have never been asked before and that is when scientists need to find the answers themselves by investigate the world, scientists carry out experiments. Many of these experiments can be extremely dangerous and so a set of laboratory safety rules is needed to reduce the risks involved.

Quick Quiz Prac 1 p. So many, in fact, that science is split into branches or disciplines. They might study why mosquito and ant bites itch. Chemistry: chemists investigate materials, chemicals and chemical reactions and how they can be used. Ecology: ecologists study how living things affect each other and the environment in which they live. They might ask about what animals are likely to become extinct if world temperatures increase. Geology: geologists study rocks, the Earth, earthquakes, volcanoes and fossils.

They might ask what causes earthquakes to happen. Physics: physicists ask questions about how and why things move and the forces and energy involved. They might ask questions about how to make bike helmets safer. You will work with intense heat, acids and other corrosive substances. It is particularly dangerous if any chemicals get splashed into your eyes. Other chemicals are poisonous and can make you extremely ill or can kill.

Broken glass and equipment pose the risk of cutting you or of fragments entering your eyes if they shatter. Safety rules The science laboratory can be a dangerous place, but it becomes far safer if everyone follows a set of safety rules. Each laboratory is different and so is every class. This means that one set of rules cannot be used by everyone. Each class needs to develop their own set of rules with their teacher to keep everyone safe.

Common sense is a good start. Always look for potentially unsafe activities in the lab and report these immediately to your teacher. What are they doing wrong? What rules would you make to minimise the risk to themselves and to others in the lab? What are they doing right and what risks are they avoiding? Worksheet 1. Identify whether the sub-branches below belong in astronomy, biology, chemistry or ecology. Understanding 4 Describe four dangers that you might have to deal with in a science laboratory.

Explain what could cause these injuries and describe what could be done to minimise the risk of them. Complete this table by identifying which senses should and should not be used. Creating 14 Without using any words, design a simple two-colour sign to tell people that: a There is a slippery surface ahead. The signs must be in only two colours and use only a few words.

Explain why these dates were important. Select one scientist from each group. L e -xploring To find out more about the branches of science, a list of web destinations can be found on Science Focus 1 Second Edition Student Lounge. The main sense a scientist uses is sight. They will also use hearing, smell, taste and touch, although sometimes it will be far too dangerous to use some of these.

In a way, a scientist is like a detective trying to solve a puzzling case. Clues must be gathered through careful observation of all the evidence. The various clues can then be linked together until a conclusion can be drawn about the case. Aim To act a set of observations to work out whom most likely stole the sausages.

Method 1 Carefully read the story on the next page. You arrive home at 3. You are surprised since, from experience, you know that wet grass is very hard to cut. You enter the house. The sausages that you left defrosting on the kitchen table are gone!

You enter the lounge room. The front window has been shattered! Pieces of broken glass are lying everywhere. The curtains are all messed up and the carpet is soaking wet and marked and smudged with mud! Some strands of blond hair are stuck on the windowsill. A small stone has been placed in the middle of the coffee table … the calling card of the sausage burglar? Questions 1 State what you want to know about the case or what you are trying to investigate.

Scientists call this the aim. In the case above, you have used many of the skills a scientist needs. You need to know the name of each piece and how to use it safely and accurately. Everyday laboratory equipment Equipment is used in science to help carry out experiments and to make observations more accurate. Chemistry experiments, for example, are commonly run in beakers and conical flasks. Measuring cylinders are used to accurately measure volumes of liquid and thermometers are used to measure temperature.

Stopwatches and electronic timers are more accurate than normal watches and clocks, and can be used for better timing. Other equipment magnifies very small objects that might normally be difficult to measure. Microscopes magnify extremely small objects, whereas telescopes magnify objects that are far away. Microphones and electronic amplifiers allow you to hear sounds that otherwise cannot be heard. You will use a lot of different pieces of equipment in the school science laboratory.

As with all equipment, there are special rules for using each piece. Your teacher will instruct you on how to safely use each one. The drawings are simple lines and curves, normally without any shading or colouring. These diagrams are known as two-dimensional 2D scientific diagrams and are used by scientists all around the world. Collar: controls the amount of air that enters the burner and controls the heat and colour of the flame. The hole must be closed before lighting.

The collar must be turned so that the airhole is closed whenever a Bunsen burner is lit. Very little air is then able to mix with the gas and so the gas will not burn well. It produces an easily visible, pale yellow flame that is relatively cool. It is also a dirty flame because it leaves a layer of carbon on anything that is heated in it. This flame is called the safety flame because it is the coolest flame and is the easiest to see. If the collar is turned so that the airhole is open then a lot of air will enter.

Although difficult to see, this flame is blue in colour and noisy. Prac 1 p. It is used to heat chemicals. Your safety depends upon using it correctly. The hottest part of the flame is just above this cone. Prac 4 p. This presents a few questions: Who should get the credit? Who does the work in science? Bunsen worked on explosive arsenic compounds, which almost killed him, and he lost one eye when a glass container exploded. Working with the German physicist Gustav Kirchhoff — , Bunsen discovered two new elements—caesium and rubidium.

Science Clip Smelly Bunsen! Bunsen was a bachelor for all his life. He developed a number of strange personality quirks, including not bathing! Identify what each of the students in Figure 1. Understanding 4 Clarify the purpose of the collar in a Bunsen burner. Analysing 12 Compare the following pieces of equipment by listing their similarities: 5 Explain why a yellow flame is called a safety flame when it is still hot enough to seriously burn you.

Applying 9 Identify a piece of equipment that you would use to: a Measure the temperature of boiling water. Creating 13 Construct a labelled 2D scientific diagram that shows the setup used for boiling water. You will need to show the bench mat, tripod and gauze mat, Bunsen burner and beaker.

We b Desti nation c micrometer d barometer e mortar and pestle f ammeter. Aim To draw, classify and name common laboratory equipment. Measuring equipment Pouring equipment Storage equipment Equipment to run chemical reactions in Safety equipment Holding equipment Cleaning equipment Mixing equipment Equipment A range of everyday scientific equipment. Method 1 In your science workbook construct a table with eight sections, as shown opposite.

Draw each piece: a as realistically as you can b as a scientific diagram. Aim 5 Turn off the Bunsen burner by turning off the gas. To correctly and safely light a Bunsen burner. Safety 1 Tie long hair back and wear safety glasses.

Bunsen burner bench mat matches safety glasses Method 1 Place a Bunsen burner on a bench mat and connect its hose up to the gas outlet. This flame should be yellow—orange in colour and is known as the safety flame. The flame should turn blue and become noisier. Science Safety Do not hold the gauze mat or porcelain in the flame with your bare hands—use tongs. Questions 1.

Questions 1 Discuss whether the yellow flame is hot enough to make the gauze mat go red. Method 1 Set up the Bunsen burner. Questions 4 Light the burner as usual. Noise of flame Airhole Colour of flame Coloured diagram of flame Coloured diagram of What happened to the gauze mat held in flame porcelain held in the flame? Closed Half open Open 4 How hot is hot? Aim To accurately measure an amount of water and heat using different flames. Safety Boiling water will burn badly if spilt.

Treat it and the hot beaker with care. Boiling will be obvious when the water begins to bubble vigorously. Safety 1 Use tongs to hold the test tube because the glass will get very hot. Questions 1 Explain why pointing test tubes at people is dangerous. As a scientist you will need to make detailed observations and to think about what you have just observed. Measurements can make your observations more detailed and allow you to see any patterns that may exist.

Qualitative and quantitative observations Scientists make two types of observations. Observations can be qualitative. This means that the observations are being written down in words only. Qualitative observations could be made about the noise a bird makes, the taste of ice-cream or a description of what happens when water is boiled. Other observations are quantitative. These observations involve measurements and are stated as numbers.

Inferring and predicting Once you have observed something, you can then make a logical explanation known as an inference as to what happened and why it happened. You may then be able to predict what might happen in the future.

Predictions must be logical and based on the observations made in your earlier experiments. You make observations, inferences and predictions every day, probably without knowing it. Consider: Observation Inference Prediction The dog barked. That possum is back again. The barking will frighten it away.

Sometimes the same observation can lead to different inferences and predictions: Observation Inference Prediction or Observation Inference Prediction The leaves are turning brown. The tree is dying. I will have to get a new one. The leaves are turning brown. It is a deciduous tree that loses its leaves in autumn. It will get new leaves in spring. In this case, a calendar could assist you in deciding which is correct. Measurements can also be arranged in tables and can be used to construct graphs.

Tables and graphs are very useful in science because they make it much easier to see any patterns that may exist in the measurements. Units Scientists use the units of the metric system for their measurements. Grams are used for measurements of small masses, like the mass of a coin or a mouse, whereas kilograms or tonnes are used for heavier objects.

Centimetres, metres and kilometres are used for length. Seconds, minutes and hours are used for time. All three failed. One is thought to have failed because NASA scientists did not write the units down for a series of measurements. One group of scientists thought the measurements were in older Imperial units, whereas another group thought they were metric. The spacecraft crashed into the surface! This causes a reading error in your measurement.

Some older Australians still use Imperial units e. These are the units they grew up with and the units they are most used to. People in the USA but not the scientists also use Imperial units including degrees Fahrenheit for their temperatures for everyday measurements. Errors and mistakes You will always have errors in your Just right: person B will read this measurements, regardless of how measurement most accurately as 20 careful you are.

Errors are not B C A mistakes. Mistakes can be avoided Too low: Too high: with care. Errors are slight person A will person C will changes in measurements that read this as A reading error, for example, is always made whenever you must guess the measurement because it 0 5 10 15 20 falls between markings on your 25 30 35 measuring instrument. Another important error is caused by not having your eye directly in line with the measurement.

This is called Fig 1. A beam balance is often used in the school laboratory to measure the mass of an object. The mass is a measure of how much matter there is in an object and is sometimes incorrectly called weight. Taking accurate measurements You need to minimise errors and make no mistakes if you are to take accurate measurements. Do not try to remember measurements. For example, always use g for grams not G or gms and mL for millilitres not ML or mls. Use decimals instead. For example, 9.

This is when the device reads some value even though nothing is being measured. An example is a weighing scale that measures 0. Mass is usually measured in the laboratory in grams, abbreviated as g. Larger masses are usually measured in kilograms kg. For increased accuracy, an electronic balance is Prac 5 Prac 3 Prac 4 sometimes used. This curve is called a meniscus.

Understanding 3 Define the following terms: L a qualitative b quantitative c meniscus d mistake e error. Be careful! There will be no fish left in the pond after a while. The cat is on the edge of the fishpond. The bigger Olympian will win the event. One can lift a heavier weight than the other.

The line is taut and the fishing rod is bending. Identify this statement as an observation or prediction. Explain your reasoning. Analysing Beaker 12 Analyse these measuring devices and state their measurements. Before Jill passed out, she wrote down everything that she saw, heard and smelt in this experiment.

Analyse what happened and list all the qualitative observations that Jill would have made. He needed to put the substances in containers instead. Complete the table opposite of his results by calculating the missing values. N 3 20 e f 2 0 0 10 20 30 40 50 60 70 80 90 0 1 2 3 4 5 6 7 8 9 10 0 0 10 20 30 40 50 60 70 80 90 0 1 2 3 4 5 6 7 8 9 10 g j h 60 14 While in hospital, Jill made some inferences and predictions about the experiment.

Classify which are inferences and which are predictions. Construct a table and present the results as they should look. Aim To observe a burning candle. Record your result. Michael Faraday, the 19th century scientist, made 53! Questions 1 How many different observations did you make? For each observation, state whether it was qualitative or quantitative. If they were different, propose a reason why. Write your measurement in your table and on the piece of paper.

Name of piece of equipment What is being measured My measurement Unit it is measured in Unit DYO Aim To develop a method that measures things without accurate measuring instruments. In groups, design your own way of measuring each of the following: 1. Explain why it would be physically impossible to measure just one of each with the equipment you were given. Aim To use a beam balance correctly to find the mass of various objects.

Questions 1 Construct a table in your workbook with the column headings Object being measured, Mass and Units. If this does not happen, adjust the balance screw on the edge of the arm. Then pull the sliding mass back one notch.

Mass g Equipment 0. N 5 Mark on your graph a length that you did not measure. To do this, they need to write a scientific report. Equipment or materials This is a list of all equipment and chemicals needed in the experiment. The sizes of the various pieces of equipment must also be included.

Risk assessment safety guidelines This can be a short statement on how you intend to minimise risks when performing the experiment. Any safety equipment you intend to use should also be included here. For many experiments, for example, you would list safety glasses and a lab coat or apron. Otherwise, you might forget some of them. Aim This is what you intended to do in the experiment, what you were trying to investigate or what you hoped to achieve. Hypothesis optional You probably have an idea of what might happen or what you might find out in an experiment.

Method This is a detailed list of what was done in the experiment. To allow another scientist to be able to repeat the experiment, you must include what quantities were used and the exact order in which the experiment was performed. This is often presented as a numbered list. A diagram of the experiment with all the equipment connected, not separate can be very useful.

You must include a complete list of measurements and observations that you took in the experiment. Results are easier to read if they are presented in a table. Always include headings and units e. This is where you summarise what you have found out in the experiment.

The conclusion should be short and must relate directly to the aim. Common mistakes made in scientific reports Writing a scientific report is sometimes difficult and students make mistakes frequently. Tony ran an experiment during which he tested the flexibility and stretch of a fishing line. His scientific report is shown below. No label What length? Spacings should be equal, and increase by the same amount Points are too big What weights?

No units Put units in headings A diagram would help here Units changed The conclusion does not match the aim Units changed 26 Fig 1. Go to Science Focus 2 Unit 1. Analysing Understanding 4 In your own words, describe what is meant by the term aim. Analyse why. Count half-covered squares as full and less than half-covered as empty. N 8 Check your predictions by counting the squares for four, five and then six drops on the slide. N Area squares Questions 80 60 40 20 0 4 Present your results as a line graph, with Area on the vertical axis and Number of drops on the horizontal axis.

N 2 3 4 5 6 7 8 Number of drops 5 State a conclusion for this experiment. Does salt make a difference? Aim To investigate if salt makes a difference to the boiling point of water. Use the glass stirring rod to dissolve the salt. Put your answer in the Discussion section of your report. Record this temperature in your workbook. Method 4 Carefully light the Bunsen burner and use a blue flame to heat the water. Use the conclusion from this experiment to propose a reason why.

They then design experiments to answer their questions. Your conclusion probably confirmed that dogs are easily bluffed, at least on the first few tries. Another example of observations leading to experiments comes from Joe, Year 7 scientist.

Joe noticed that when he washed dishes he sometimes made lots of froth and at other times he made almost none. Joe has a problem. Observations can lead to experiments Most likely, you have already run an experiment based on observations you have made about the world.

It might be as simple as throwing a ball to a dog. Throw the ball and they fetch it. This observation has probably led you to wonder what would happen if you pretended to throw the ball. It has a clear aim to test if a dog can be bluffed by a pretend-throw and hypothesis Fig 1.

Fair tests and variables Things happen due to lots of different factors, but it is sometimes difficult to determine which factor has the biggest effect and which ones have no effect at all. Any test that a scientist carries out must be a fair one.

To be fair, you must change only one factor at a time. These factors are called variables and are anything that may affect the results of an experiment. These were his variables. From their observations, scientists then make a hypothesis. Joe had noticed that more froth was produced when faster tap water was added and when more detergent was used. This was his hypothesis. Planning experiments Scientists change only one factor or variable at a time. Otherwise they would not be able to work out which variable caused the effect.

All the other variables must be kept exactly the same or constant. Go to 30 Science Focus 2 Unit 1. Experiment 1: He put three drops of detergent in the sink each time. He ran hot water in very slowly at first, then repeated with hot but faster water.

He repeated the experiment with very fast but equally hot water. Each time he filled the sink half-way. Experiment 2: He put one drop of detergent in the sink and turned the tap on high until the sink was half full. He then repeated the experiment with two drops of detergent, then three and then four. Prac 2 p. Understanding 1 Define the term variable.

For this new experiment: d your test results for this topic. List the four variables. Applying 1. Questions 1 State the variables that Joe tested. DYO Answering a question with an experiment 2 Travis noticed that when he dropped a ball, it never bounced back to the same height from which it was dropped.

Aim To identify variables and design a simple experiment. You will need to collect at least five different measurements. Equipment Prepare a list of the equipment you intend to use. Safety Once you have decided on your topic and method, write your own risk assessment, listing all the possible dangers that may be involved and what can be done to minimise them.

Method 1 Read the following investigations and choose one of them to run as an experiment. Whichever investigation you choose: a Identify three variables that are likely to have an effect on the results. List them in order from what you consider to be the most important to what you consider to be the least. She often noticed, however, that a lot of it remained undissolved at the bottom of the cup.

She wanted to find out why the amount on the bottom differed each time. He thought this sounded weird and wanted to see if it was true. Creating 12 You have often wondered whether your cup of hot chocolate will cool down faster in a glass cup or a polystyrene cup. Design an experiment to test this idea. Unit 2. Although the same type of particles make up ice, steam and tap water, the three materials behave very differently.

The particles that make up solids, liquids and gases are far too small to be seen even with a microscope and so scientists use a model to explain their various properties. Scientists, architects and engineers also use physical models of things such as buildings, ships, aircraft and landscapes.

These models can be used to test how a skyscraper might respond in an earthquake or how a flood may affect the shape of a river valley. Likewise, a model aircraft can be tested in a wind tunnel to see how a newly shaped wing cuts through the air. Sometimes scientists use a model to describe an idea or concept that helps them explain how something works.

This type of model is particularly useful when they are investigating something that cannot be seen, such as the structure of the atom the atomic model. The model might not be exactly right but it can be used to understand and predict how things behave and react—just like a model aircraft helps designers better understand the real thing.

For example, scientists cannot see individual particles of water, but they can observe how water and ice and steam behaves. From these observations scientists have developed the particle model to better understand different forms of water and other solids, liquids and gases. The particle model Fig 2. Models in science Quick Quiz Scientists often use models to help them understand the world and the way it works. Computer models, for example, are commonly used to simulate weather patterns and to predict the movements of the planets, tides and tsunamis, and the effects of earthquakes.

Matter is the basic building material from which substances are made. Everything in the universe is made of matter—from stars to spiders, galaxies to geckos and planets to people. Matter has mass and takes up space. There are three states of matter—solids, liquids and gases.

Ice, water and steam, for example, are all water, but in different states, or phases. To explain the behaviour of solids, liquids and gases scientists use a model known as the particle model. This model proposes that all matter is made up of tiny, invisible particles and explains the different states in terms of how these I n t e r a c t i ve particles move and stick together. The particles in liquids and gases all vibrate too. These particles can move about freely though, giving liquids and gases the ability to flow and move about.

Iron, plastic, wood and sponge are all solids with very different characteristics. All solids, however, share some common characteristics, which are known as the physical properties of solids. The particle model explains these properties by imagining that the particles within the solid are bonded strongly to each other and packed very closely together. Properties of solids Particle model of solids Solids have a defined shape and do not flow.

The particles are strongly bonded to their neighbours, so their position is fixed. Solids are virtually incompressible. There is very little space between the particles, so they cannot be pushed any closer together. Solids expand when heated and contract when cooled. Heating causes the particles to vibrate faster, pushing them further apart and causing the solid to expand.

The reverse happens when the solid is cooled. Science Clip Viscosity and quicksand Viscosity describes how easily a liquid flows. Water flows easily and so has a low viscosity, whereas honey, which does not flow as easily, has a high viscosity. The best way of getting out is to move through it slowly and smoothly. These properties can also be explained by the particle model. In this model, the particles in a liquid are packed very close together and can move around freely.

Although most gases are invisible, they are extremely important to life on Earth. The air Prac 5 p. In the particle model, gas particles are not bonded to each other at all. This allows them to move around freely anywhere within their container. Properties of liquids Particle model of liquids Liquids flow to take the shape of their container.

The particles are weakly bonded to their neighbours. This allows the particles to move freely within the liquid. Liquids are virtually incompressible. There is very little space between the particles, so they cannot be pushed together any further. Most liquids expand when heated and contract when cooled. Heating causes the particles to vibrate faster, forcing them further apart and causing the liquid to expand.

The reverse happens when the liquid is cooled. Fig 2. The experiment began in and is still running! The aim of the experiment is to determine the viscosity of pitch, a black liquid that is so viscous it appears to be solid—even brittle. Professors John Mainstone and Thomas Parnell began the experiment by putting some pitch into a large funnel and started counting the drops oozing from its tip. Today, the ninth drop is only just starting to form!

This suggests that pitch is billion times more viscous than water. Properties of gases Particle model of gases Gases have no fixed shape and will spread to fill their container. The particles are not bonded to each other and so are free to move anywhere within their container.

Gases are compressible. Lots of space between the particles allows them to be pushed closer together easily. Gases expand dramatically when heated and contract when cooled. Gas particles are constantly moving. Heating a gas causes the particles to move faster and move further apart. This causes the gas to expand. The gas contracts when the gas is cooled and the particles move slower. In a confined space, heating increases the pressure of gases. The pressure decreases when cooled. In a confined space, heating the gas causes the particles to collide with the sides of the container more often and with greater force.

Pressure depends on force and so it increases too. The pressure decreases when the gas is cooled and there are fewer and less forceful collisions. Scientists should be objective at all times. This means that they should only rely on evidence collected from experiments that have been repeated many times around the world. The particle model is not just an idea. This evidence has come from repeated experiments. In this case, one jar of brown nitrous oxide gas is mixing via diffusion with a jar of colourless air.

Dissolving Although a sugar cube seems to disappear when it is dissolved in a hot cup of tea, its sugar particles are still there—you can taste them! The water particles in the tea have pulled the sugar cube apart and spread the sugar particles throughout the cup.

Go to Prac 6 p. Solvent particles e. The liquid is known as the solvent. Solute particles e. Solute is the substance being dissolved. Natural gas methane, CH4 is normally odourless, making it undetectable if there is a leak or something is left on. To make natural gas extra smelly, chemicals called mercarptans are added to it.

Mercaptans are the smelliest substances on Earth. The human nose is so sensitive to them that it can detect one mercaptan particle amongst several billion molecules of air. The solid that dissolves is known as the solute. The liquid that dissolves a solute is known as the solvent.

Diffusion nose The smell from an open bottle of perfume will quickly reach you, even if you are on the other side of the room. The gas particles have travelled across the room via a process called diffusion. Science In the particle model, gas particles move quickly. Some smells zig-zag path from the we find pleasant, others are bottle. Particles may also nasty and others naturally diffuse through solids and evoke fear. Clip 38 nostril Fig 2. Science Clip Penis-eating fish! In , two men in Papua New Guinea had their penises bitten off by piranha-like fish.

The men had been fishing, standing up to their waists in the Sepik River. They had a wee in the water and the urine diffused far and wide until the fish sensed it. The fish followed the faint urine trail and bit off its source! Unit Brownian motion 2. He saw that the pollen grains were constantly moving around as if they were being jostled by something. This jiggling motion is now known as Brownian motion and can be easily explained by the particle model.

The particle model explains that the water particles are vibrating and moving about, bumping into the pollen grains. This jiggling is known as Brownian motion. Applying 12 Identify a food or drink that contains: 2 List five different examples each of a solid, a liquid and a gas. Clarify the definition of a solid so that people cannot make this mistake. Explain how this can be. Justify this statement. Creating 19 Construct your own version of the particle model.

Draw it as three layers, with solid at the bottom, changing into liquid and, finally, gas at the top. Design an experiment to demonstrate it. Explain how temperature affects the viscosity of honey. Compile a summary of the states of matter and their properties using only labelled diagrams. Find out how to make a substance that acts like a liquid and a solid. In this role play you will experience the movement of particles. Aim Use role play to simulate how particles move in a solid, liquid and gas.

In particular, think about how you will represent the movement and bonding of the particles. Question Write a description of the movement of the class members to describe and contrast each state of matter. Plasticine particle models Aim To build a model showing the arrangement of particles in various solids.

One way is shown in Figure 2. Aim 4 Use the plastic spoon again to measure out three spoonfuls of borax solution into the second cup. Describe what it does over five minutes. Describe how the silly putty changes shape over time. One or two drops of food dye no more can be added at this stage.

Comparing viscosity DYO Viscosity describes how easily a liquid flows. Questions Aim To rank liquids according to their viscosity. Method 2 Assess your experiment and determine how you would do things better next time. Questions 1 State which substance you were able to compress. It is through observation and experiment that we have been able to reach our present understanding of matter. Although we cannot see the particles, there has always been evidence available for those who are observant enough to notice it, and interested enough to try and understand what they see.

By early in the nineteenth century, experiments on the behaviour of different states of matter had led to the kinetic theory of matter. Part of this theory stated that all the tiny particles of matter move constantly. The model of tiny particles of matter that developed was all based on deduction making conclusions based on evidence rather than on direct observation of the particles themselves.

Having made observations, a good scientist will then investigate further, to try and understand what they have observed. The Scottish botanist Robert Brown — was an enthusiastic scientist whose search for an understanding of the world led to the first observation of molecules in motion. He sailed to Australia and collected vast numbers of Australian plants. When he returned to England, Brown used a microscope to study the plants.

It was while using his microscope to make observations on tiny pollen grains that he made an interesting observation. Brown could see them jiggling and slowly moving about in zig-zag paths through the water. Knowing that the tiny pollen grains were not alive, Brown wondered why they appeared to be moving about. To investigate further, he placed a tiny drop of a stain into a drop of water on a microscope slide.

He was surprised to see that the tiny particles of the stain also jiggled about and moved in the drop of water. Brown was unable to provide a full explanation for his observations, but he reported his findings anyway. Regardless, his findings supported the suggestion that all tiny particles of matter move constantly. The motion of tiny non-living objects jiggling about and moving through a drop of water became known as Brownian motion.

In the diagram, the blue lines represent the movement of the blue water molecules, and the wiggly red lines show the movement of the pollen grains. L 44 4 Brown mounted the pollen grains in water at room temperature. Another experiment that would have been useful would be to place identical pollen grains into a drop of warm water. Heating or cooling a substance might just simply alter its temperature.

Sometimes, however, the substance might change state. It often forms rounded droplets like these drops of mercury. Mercury is the only metal that is a liquid at normal room temperature. Applying a model melting. A solid wax candle, for example, absorbs Ice changes state when it melts.

It absorbs heat energy enough heat energy from the flame to melt and from whatever is around it e. Likewise, the solid wax of a candle is quickly turned into a liquid after the candle is lit. Some of the Melting point wax is also turned into a gas that keeps the flame burning.

The temperature at which a particular solid changes Most substances change state if enough heat energy into a liquid is called the melting point. The table is added or removed from them. This process can be below shows the melting point of various substances. Substance Solid to liquid Water To change a solid e. This causes solids to expand. When a liquid loses energy, the vibration of particles lessens and the bonds between particles are once again strong enough to keep them in fixed positions.

Boiling point The temperature at which a liquid boils is called its boiling point. Some sample boiling points are shown in the table below. As freezing and melting are the reverse of each other, the freezing point and the melting point of a substance occur at the same temperature. Table salt Gold Diamond Evaporation A liquid does not have to boil for vaporisation to occur—boiling just speeds up the process.

Evaporation is occurring whenever a liquid changes into a gas at a temperature below its boiling point. The warmer the liquid, the faster the rate of evaporation. A puddle of water will eventually evaporate on a dry day as particles at the surface absorb enough energy from the air to escape the liquid. It will Prac 1 p. Liquid to gas A liquid changes into a gas when heat completely breaks the bonds between the particles. When heat is added to a liquid, small bubbles of gas soon begin to form within the liquid.

When enough heat is added, these gas bubbles become large enough to float to the surface and boiling occurs. When a liquid boils, bubbles of gas escape into the air. This is known as vaporisation. Gas to liquid The opposite of vaporisation is condensation.

Condensation occurs when gas particles lose heat energy and turn into liquid. When you breathe out on a very cold day, the water vapour in your breath a gas condenses to form tiny droplets of water that are suspended in air and appear fog-like. A similar thing happens when you breathe on a window. Small water droplets condense on the glass, making it difficult to see your reflection. Unit Sublimation is a much less common change.

Sublimation occurs when a solid absorbs heat and changes directly to a gas without melting and going through the liquid phase. An example of sublimation is when dry ice frozen carbon dioxide sublimes to form carbon dioxide gas. Sublimation is also the word used when a gas changes directly into a solid.

Breathing onto a cold mirror causes the vapour in your breath to condense into a fine film of liquid water droplets. Worksheet 2. Science Clip Lord Kelvin, superscientist! William Thomson was born in in Belfast, Ireland. William was one bright kid, starting university when he was 10 years old and becoming a professor at 22! Work is being done on the water. Some heat and sound is generated. Unit 5. Newton Unit for force.

The levels dropped slowly over three hours to about the same level as those of a low-GI food. The low-GI food raised the blood sugar levels but not as high as the high-GI food. With the low-GI food, the blood sugar levels dropped more slowly after peaking. The blood sugar levels for the high-GI food would probably continue to drop further. For example, it could be due to the chicken, which may have come from a bulk supplier, or it could be because the cream in the desserts was not kept cold enough.

The important thing is that students offer a plausible explanation for their hypothesis. The victims should be questioned again about their movements in the days prior to their illness. Food in their own homes should also be tested. It must be ascertained which common suppliers the eateries shared. Also, when it was sitting in the schools at room temperature, there would have been further bacterial growth.

This disrupts blood flow and eventually kills. For example, in some countries, prostitution is rife and illicit; unprotected sex is the norm; unhygienic medical services; denial; poor education; lack of access to things like condoms. Usually 1. Stubbies or mixed drinks in bottles or cans contain more than one standard drink, but each brand varies.

Someone could refill your glass before you finish it, so you do not know exactly how much you have had. Unit 6. Using human fingers would be too easy. This is because it was easier for predators to see dark-coloured moths when the trees became lighter.

The light-coloured moths became better adapted again. The graph shows how the environment changed to the advantage of the dark moths. A total covering of cement has formed. The one-toed foot allows greater speed over harder ground to escape predators on the grasslands. In addition, the development is of features more suited to new surroundings, not necessarily development of a more complex form.

The discovery was made at Liang Bua, a large limestone cave on Flores, km east of Bali. The nearest anatomical equivalents lived almost 2 million years ago, with some features of the find harking back to 3 million year old human ancestors in Africa. They were the height of a three-year-old child, weighed around 25 kg and had a brain smaller than most chimpanzees.

They look at dating what they find, the anatomy of fossils, and the behaviour. So they try to contextualise and get a broader picture of what the fossil tells us. Also it may give evidence of how humans adapt to different environments. Not all human species are the same. Some information may also be gained about how humans affect the environment they live in.

This type of information can be applied to better understand how we live now and in the future. Unit 7. Buffon One of the earliest naturalists to suggest the idea of evolution. Lamarck Proposed evolution by the inheritance of acquired characteristics. Wallace Along with Darwin, he proposed evolution by natural selection. Mesozoic era The age of the reptiles. Archaeopteryx A fossil bird-like reptile. Cenozoic era The era in which humans are thought to have first appeared.

Homo habilis Early fossil form known as handy man. Homo erectus Early fossil form known as upright man. Homo sapiens The species to which you belong. City Temperature rise predicted in Temperature rise predicted in Canberra 2. Warm air forms here as the land warms up due to sunlight.

Being inland the area will be less likely to cool down as much at night, keeping the average temperature considerably higher. Alpine areas around Canberra may change due to this, with different vegetation taking over higher regions and some plants and animals having to move or becoming extinct.

Initially this is caused by humans releasing more carbon dioxide and greenhouse gases into the air through processes such as land clearing and burning fossil fuels. Diagram of the greenhouse effect may help in this answer.

In the years and the thickness appeared to be increasing. A similar trend occurred in and Between September and November the ozone hole is thinnest. This coincides with the start of summer in Antarctica. In and the ozone hole was always at least DU thinner than in and , and the hole at its thinnest was up to DU thinner than in the previous years.

This again supports the claim that the ozone layer has thinned over the years, as the first graph does. Richmond Windsor r ive nR. Galston ea. M5 8 km Maroubra Hurstville Revesby. Botany Bay. Menai Ingleburn 16 km. Heathcote Motorway-highways Other main roads.

Unit 8. CFC s Chlorofluorocarbons. Dobson Units for measuring the ozone layer. Montreal Protocol in which countries agreed to ways of reducing CFC emissions. Antarctic Region on Earth over which the ozone hole appears. Word Clue radiation Fast-moving particle or electromagnetic wave.

Chernobyl Site of a major nuclear reactor accident. Maralinga Site of British nuclear tests in Australia. Unit 9. Being interested helps improves this aspect of yourself. Open navigation menu. Close suggestions Search Search. User Settings. Skip carousel. Carousel Previous. Carousel Next. What is Scribd? Uploaded by Ollie Cruz. Did you find this document useful? Is this content inappropriate? Report this Document.

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Hypothese bij spellings problemen thesis What type of mine is Na needed? Unit 2. This causes solids to expand. Bunsen was a bachelor for all his life. One is inherited from the mother and one from the father.
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Financial analyst resume due diligence This allows steel rods to be used as reinforcement for concrete with no risk of cracking. Some practical activities are design! Applying a model melting. Michael Faraday, the 19th century scientist, made 53! City Temperature rise predicted in Temperature rise predicted in Canberra 2. Once the oxygen in science focus 4 homework book online D is used up no more will be able to enter because the oil will stop this occurring, so tube D will only rust a little and then stop.
Science focus 4 homework book online Questions incorporate the key verbs, so that students can begin to practise answering questions as required in later years. All paperwork must More information. Solvent particles e. In this case, one jar of brown nitrous oxide gas is mixing via diffusion with a jar of colourless air. Aim To identify variables and design a simple experiment. The particle model Fig 2. X chromosomes Females carry two of these chromosomes.


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