Science

Y9 Homework Booklet

? ??

Contents

Unit PagesHealth and Fitness 2 - 9Homeostasis 10 – 15Human Impact 15 – 21Variation 21 – 30Chemical Reactions 30 – 35Particles 35 – 41Electricity 41 – 49Forces 49 – 56Space 56 - 60

1

Health and Fitness

Homework One – Healthy Heart and Pulse Rate

Three students measured their pulse rates before a game of squash. They measured their pulse rates again after the game every minute for 5 minutes. The table shows their results.

Pulse rate /beats per minuteStudent A Student

BStudent C

Before exercise 72 65 751 minute after 170 144 1782 minutes after 142 115 1323 minutes after 96 70 1054 minutes after 82 65 925 minutes after 75 65 84

1) Which student had the highest pulse rate after the game of squash?

2) What is meant by recovery time? How long was student B's recovery time?

3) Which of the three students was the fittest? Give two reasons for your answer.

4) Suggest three pieces of advice you could give someone to help prevent the risk of a heart attack.

5) Where in the body does the process of respiration take place?

2

Extension

Read the following information.

During the process of respiration, chemical reactions take place. These chemical reactions:- · use up oxygen and glucose · produce carbon dioxide and water · release energy

1) Use this information to complete the following diagram.

2) How is the carbon dioxide removed from the body?

3) State one way in which muscles use the energy released in respiration.

3

Homework Two – Breathing and Smoking

The diagram shows a model which can be used to demonstrate breathing.

1) Name the part of the body represented bya) the balloonb) the glass tube Ac) the glass tube Bd) the sheet of rubber.2) When the rubber sheet is pulled down the

balloons inflate. Explain how this is caused.

The graph on the next page shows the death rates from lung cancer of people who have stopped smoking.

4

3) What is the death rate for smokers?4) How does the death rate change. 2 years after

stopping smoking? 8 years after stopping smoking?5) How many years does it take for the death rate

to drop from 100 deaths per 100,000 to 28 deaths per 100,000?

Extension

1) Describe how you would use the information in the graph to persuade someone who had just stopped smoking not to start again.

Homework Three – Diet and Drugs

1) Copy out and complete the following table of nutrients and their effects in the body by filing in the boxes with the most appropriate word or words.

5

Nutrient Use in body Symptoms of deficiency

iron (i) anaemia- too few red blood cells

(ii) absorption of calcium from food

(iii)

calcium strengthening of bones and teeth

rickets-soft bones and teeth

vitamin C

(iii) scurvy-bleeding gums, poor wound healing

2) Explain why people with anaemia always feel tired.

3) In addition to vitamins and minerals a balanced diet should include carbohydrates, fats, protein and fibre. Explain why each of these nutrients is needed.

4) Explain why too much fat in the diet is unhealthy.

5) What is this purpose of digestion?

6) Alcohol is a drug. Which property makes alcohol a drug?

It is soluble in water.It is a chemical.It can provide energy.It affects the nervous system.

7) Which of the following statements could be used to explain why alcohol in the blood could cause accidents?

Alcohol cools the body.Alcohol increases the time a person takes to react.Alcohol is a stimulant.Alcohol makes a person happy.

Extension

Read the following passage and answer the questions below.

6

Drugs and drug abuse

Drug abuse is commonly described as the use of drugs which leads to either physical, mental, economic or social harm to the user or to other people who may be affected by the user's behaviour. The term is commonly associated with the misuse of illegal drugs such as heroin, LSD, cocaine and barbiturates but it applies equally to drugs such as tobacco and alcohol and drugs obtained by prescription. Dependence on drugs falls into two categories - 1. Psychological dependence is an emotional state of craving for a drug whose presence in the body has a desired effect or whose absence has an undesired effect. Most people are very mildly dependent on the caffeine in tea or coffee. Dependence on cannabis falls into this category. 2. Physical dependence is a condition where the body undergoes chemical changes as a result of taking the drug and deprivation of the drug causes physical symptoms called withdrawal symptoms. In the case of heroin, an addict who is deprived of the drug will within a few hours develop severe abdominal pains, sweating and muscular tremors. In some cases, the symptoms can be fatal. The dangers to the health of the addict range from the danger of an overdose to diseases such as AIDS and blood poisoning transmitted by infected needles which are often shared. Addicts have a high death rate from liver disease and damage to the kidneys and brains are common.

1) Name three illegal drugs named in the passage.2) Explain why the body becomes physically

dependent on a drug.3) Name two withdrawal symptoms given in the

passage.4) Suggest how drug abuse can lead to social or

economic harm to the addict.

Homework Four – Disease and Illness

1) Disease can be caused by microbes such as bacteria. Name two other types of microbes which can cause disease.

7

The diagram shows the structure of a bacterial cell.

2) Use the information in the diagram to write a description of a bacterial cell.

3) Explain how microbes cause disease.

The body has a several ways of preventing microbes entering the body. Study the following table

Name of disease

Type of causativ

e organism

Method of spread

Method of prevention or

treatmentPoliomyeliti

s virus through air and water immunisation

Measles virus through the air immunisation

Chickenpox virus through the air immunisation

Tetanus bacteriumthrough infected

cutsimmunisation

Blood poisoning bacterium

through infected

cutsantibiotics

AIDS viruscontaminate

d body fluids,sexual

intercourse

no treatment available

Tuberculosis bacterium through the

air immunisation

Pneumonia bacterium through the air antibiotics

Diphtheria bacterium through the immunisation

8

airFood

poisoning bacterium contaminated food antibiotics

4) Which disease is caused by a virus and spreads through water?

5) Which bacterial disease is spread through contaminated food?

6) What do the diseases that are treated with antibiotics have in common?

7) Tuberculosis can affect a number of body organs but commonly affects the lungs. Describe how the disease spreads from one person to another.

Extension

1) For each of the following state how it helps to preserve food.

a) vacuum packing.b) dehydration.c) canning.

9

Homeostasis

Homework One – Organ Systems, The Skeleton and Joints

1) Explain what the word homeostasis means.2) Name the nine organ systems.3) Describe the role of each of these systems in

homeostasis.4) a) The skeleton performs three important jobs in our

bodies. What are they?b) Which organs are protected by the (i) skull

(ii) rib cage5) Label the circled

joints as one of the three main types of joints in the human skeleton (e.g. fixed, hinge, or ball and socket).

Extension

1) The table below contains a list of words and definitions, but they are matched up wrongly. Copy out the word, and then write the correct meaning by it.

10

A

B

CD

E

F

Muscles This keeps the synovial liquid inside the joint.

Tendons When the muscles pull these the skeleton starts to move.

Synovial cap

These cause the bones to move by pulling on them.

Synovial liquid

This holds the whole joint in place.

Bone This is a smooth covering on the end of the bone. It acts as a shock absorber.

Cartilage This liquid lubricates the movement of bones so they don’t wear out.

Ligament These join the muscles to the bone.

2) a) If the triceps contract, what happens to (i) the biceps and (ii) the lower arm?b) Explain why we need two muscles to move our lower

arm. Use the words push, pull, contract, relax and antagonistic.

Homework Two – Control of the Body

Conditioned reflexes:Read the following passage and then answer the questions in full sentences.

11

“In most simple reflexes, the stimulus and the response are related. For example, the chemical stimulus of food in the mouth produces the reflex of salivation. After a period of learning or training, however, it is possible for a different and often irrelevant response to produce the same response. In such a case, a ‘conditioned reflex’ has been established, and the animal is said to be conditioned to this stimulus. Pavlov, a Russian biologist, carried out a great many experiments on dogs regarding conditioned reflexes, one of which has become a classic.

The smell and taste of food is a stimulus that activates a dog’s salivary glands, making it’s mouth water. For several days Pavlov rang a bell at the time the food was being served to the dogs. Later the sound of the bell was a sufficient stimulus to cause the dog’s mouth to water, without sight or smell of the food. The original chemical stimulus of the food has been replaced by an unrelated stimulus through the ears.”

1) What is a reflex (give an example different from above to help your explanation)?

2) Explain the terms a) stimulus and b) response (using your above example to aid your explanation).

3) What is a dog’s normal reflex to the smell of food?4) Why did the ‘conditioned’ dogs produce saliva when

the bell was rung?5) Describe any conditioned responses that you have

acquired.

Extension1) Most reflexes exist to protect our bodies from harm.

Make a list of as many reflexes as you can that we have. For each one explain what its role is in our protection.

2) Describe fully what happens in our bodies when we accidentally pick up a hot frying pan.

Homework 3 – The Skin and Temperature Control

1) What is the body temperature of humans?

12

2) Explain how the two parts of the skin labelled below help with the control of temperature in the body.

3) Explain how blood flowing in the skin can change to help control body temperature.4) What else can humans do to control their body temperature.

Extension1) The skin is made up of a top layer of dead cells. What

is this layer called and what is its main job?2) What is the name of the layer of living cells in the

skin?3) The skin has many sensors within it. For each of the

following sensors write down i) what it senses?ii) where does it send the information to?iii) what is the response by the body?

a) The pain receptorb) The heat sensorc) The cold sensor4) What can be the effects of our bodies overheating or

cooling down too much? Give examples of when this may happen

Homework Four – The Excretory System

1) What waste products do humans need to remove from their bodies?

13

A

B

2) Copy the diagram of the urinary system below and label the parts shown.

3) Where does the 2 litres of water you need to drink everyday go? What happens to it? Does it all become urine?

4) What else does the kidney control other than water level?

Extension

1) (a) In humans, glucose is formed by the digestion of a polymer (large molecule) of glucose. Give the name of the polymer.

2) Glucose is absorbed from the small intestine into the blood stream and is carried to the liver. Which part of the blood carries glucose?

3) Glucose molecules cannot be stored in the body. They are converted into a compound which can be stored in liver cells. What is the name of this compound?

4) During a long distance run on a hot day, an athlete produces large quantities of sweat.

(a) The production of large quantities of sweat affects the composition of the blood. Give one way in which the composition of the blood will change.

14

A

B

C

D

(b) How would the rate of urine production by the kidneys change during the long distance run?

Human Impact

Homework One - PollutionMany things we use cause pollution. Examples are the car, burning of fossil fuels to make electricity and treating crops with fertilisers which subsequently get washed into rivers.

1) You have just been elected for the green party. In your manifesto you said you would cut down on polluters. Describe what you would do, and how it would cut down pollution, for each of the three examples given above.

2) Make a leaflet (using a whole page in your book) describing the problems caused by so many people using their cars. Make it colourful, and try to give as much information as you can.

3) Many more children now have asthma than 20 years ago.a) What is the main reason for this?b) Why do you think children and old people are more

greatly affected by air pollutants than people in their twenties and thirties?

Extension

Every year in Britain we cut

15

down hedges and trees to make bigger fields so we can grow more crops. In the developing world local people cut down rain forests to grow enough crops for families to eat.

16

Politicians in England and other European countries are always telling developing countries to stop cutting down the rain forests.

1) You are a journalist writing

17

a report about the state of the planet. Record a conversation between the two politicians. Try to cover as many of the arguments as you can in this discussion, explaining how

18

each of the politicians feels.

This area used to

be forest. It was all cut down to provide people with the raw materials to build.

2) If we are to protect our environment, what kind of changes do the human race have to go through?

Homework Two – Food ChainsLevel 3-6

1) Copy out the following table. For each pair of animals write down which is the predator and which is the prey. The first one has been done for you.

Animals Predator Preycat / mouse cat mouse

caterpillar / thrushsheep / humaneagle / blue tits

19

deer / leopard

2) A food chain shows how food (and energy) is passed from one living thing to another, e.g. grass sheep manPut the following food chains in order:a) cat, pond weed, gold fishb) wheat, owl, mousec) grass hopper, lizard, plants

3) All food chains start with plants. Where do plants get their energy from?

4) What is the process that plants use to make their energy?

Level 5-7

1) A pyramid of numbers shows us how many organisms there are at each level of the food chain.a) Why are there so many plants at the bottom of the

pyramid?b) Why are there so few predators right at the top of

the pyramid?c) Use one of the food chains that from Question 2

above to show what a pyramid of numbers looks like.

2) It is much more efficient for humans to use wheat to make bread and eat that, rather than to feed wheat to chickens and then eat them. Explain why this is so.

3) Why do you think meat is so much more expensive than vegetables?

4) In the 1960s farmers sprayed their crops with a strong pesticide called DDT. Describe how this chemical could then get into humans.

Extension

Plants make food using sunlight, taking in necessary nutrients from the soil. These plants are eaten by animals. When the animals die and rot, the nutrients go back into the soil. The diagram shows a more detailed picture of what is going on in the environment.

20

Use this diagram to answer the following questions.

1) What are three processes which return carbon dioxide gas (CO2) to the air?

2) What are the two main ways in which carbon dioxide gas is removed from the air?

3) What would happen if suddenly all the plants were to die? Use the carbon cycle to try to explain the effects.

4) Carbon is stored as fossil fuels (coal and oil). What will happen to the levels of carbon dioxide in the atmosphere if we continue too burn large quantities of fossil fuels?

21

22

Homework Three - Herbicides

A field was treated with a weedkiller. The bar chart shows the number of different weeds before and after treatment.

1) Which type of weed was affected most by the weedkiller?

2) Calculate the percentage decrease in the number of dandelions 1 week after treatment. (Show your working)

3) Suggest two reasons why the number of daisies shows an increase 6 weeks after treatment.

4) Suggest the impact of the decrease in plant numbers on the invertebrate populations within this field.

Homework 4 - Sewage

The graph shows the effect of sewage entering a river on the oxygen level and the relative numbers of bacteria and fish.

23

40

35

30

25

20

15

10

5

0

Before Treatment

1 week after treatment

6 weeks after treatmentnumber of

weeds

dandelions daisies buttercups plantainstype of weed

Sewage waterHigh

Low

Relativenumber

oxygen

fishbacteria

0 2 4 6 8 10 12

Distance downstream

1) How are the bacteria affected by the sewage entering the river?

2) How are the fish affected by the sewage entering the river?

3) What is the reason for this change?4) As the distance downstream increases the

concentration of sewage falls. Suggest two reasons for this.

Variation Homework

Homework One – Variation Between Species

1) Copy and complete this passage:

Each of us is an individual. We look …………… from each other and also …………… in different ways. Some of our characteristics come from the way we live our lives; these are called e……………… factors. Examples of these are ……………… and ……………… . Other c……………… comes from our parents. These are called h…………… factors. These include ……………… and ……………… .

hereditary eye colour accent gender different characteristics behave skin tans

environmental

2) Some of our characteristics are said to be continuous, such as height. Explain what the word

24

continuous means include an example of what a continuous graph looks like. Explain how the look of the graph shows that the characteristic is continuous.

3) Do the same for discontinuous characteristics, such as, the ability to roll your tongue.

4) For the list of words in the box, write downa) the inherited characteristicsb) the environmental characteristicsc) the continuous characteristicsd) the discontinuous characteristics.

freckles accent height tongue roller shoe sizeability to speak German good swimmer having

asthma appendix scar hair length hair colour eye colour

gender if you bite your nails a beer gut

ExtensionIn 1984, Professor Alec Jefferies discovered how to make a genetic fingerprint. This shows up the DNA from the body cells as a pattern of dark bands (a bit like a bar code on food). Every person’s DNA pattern is unique. If you can match DNA from a crime scene with a person’s DNA,

then you can prove that they were definitely there. DNA can be extracted from the blood, skin, sperms, hair or any other part of the body.Making a fingerprint:

First the DNA has to be extracted from the cells and then enzymes are used to break the molecules into short pieces. The fragments are put onto a special gel and a high voltage current is applied. This moves the fragments along the gel. Smaller bits get moved further than bigger bits, so the fragments spread out forming bands. The bands are invisible so next they are reacted with a radioactive chemical. Now the bands are radioactive, which means when they are pressed onto photographic film (which is then developed) dark patches appear where the bands were and the DNA pattern can be seen. A genetic finger print has been made.

25

1) Using the information on the previous page, put these 10 steps in order, and fill in the missing gaps.

Break DNA into bits using e……………

Label bands with a r…………… chemical.

Match the DNA from the c…………… scene with the suspect’s DNA

Collect samples of tissues from the crime scene

Decide who did it

Repeat the process using b…………… or other tissue from suspects

Extract D…... from tissue.

Apply an electric current to spread bits out into b……………

Press onto p…………… film and develop

Put bits on gel

2) Find out what DNA stands for. What is its structure?

26

Homework Two - Inheriting Variation

1) Copy and complete:

Hereditary ……………… are inherited from parents and cannot be ……………… . Examples are eye colour and ………… group. ……………… characteristics are not inherited. They happen after a baby has been ……………… and may change during life. Examples are scars from operations and speaking with a Derbyshire ……………… . Continuous variation is a gradual change from one characteristic to ……………… with many in-between stages, for example height or ……………… . Discontinuous variation has no ……………… stages. These characteristics are completely …………… , for example, you are either male or ………………, and not something in-between.

another different born environmental femalein-between changed blood characteristics weight

accent distinct

Each of the cells in the human body contains a nucleus. Inside the nucleus are 46 chromosomes, the structures which carry the genetic information. These chromosomes arrange themselves into 23 pairs, one member of each coming from each parent. When the sex cells, a sperm cell or an egg cell, are made, the chromosomes in each pair is split up. This means that each sex cell contains only 23 chromosomes. At fertilisation the sperm cell, carrying 23 chromosomes, joins with the egg cell, also carrying 23 chromosomes. This makes up a new cell of 46 chromosomes, which then starts to grow and divide to make a new baby.

2) Which structure within the nucleus of a cell is it that codes for what the cell does?

3) How many chromosomes do you find in a human hair cell?

4) Out of these chromosomes, how many originally came from the mother and how many from the father?

27

5) Which cells in the human body do not contain 46 chromosomes?

6) What happens at fertilisation to the number of chromosomes?

7) Using the above information and your answers, explain why you have parts of you that look similar to your father and other parts that look similar to your mother?

ExtensionLook at the below diagram which gives you further

information about genes, chromosomes and DNA.

1) Copy out the three sentences from the diagram (marked with an arrow ) and fill in the missing words.

2) Use the above diagram to explain to a year 8 student what the relationship is between the nucleus, chromosomes, genes and DNA. Remember they have heard very little about genetics before. It may help to use cartoons (remember Jurassic Park).

3) Explain why you have a different genetic finger print to anyone else, including your brothers and sisters.

28

Homework Three – Genetic Squares

Genetic squares can be used to work out gene combinations when plants or animals (including humans) reproduce.Chickens

1) Copy out the following information:“The genes for pure breeding black chickens are BB.

29

The genes for pure breeding white chickens are WW.In this example, both genes are equally strong. As neither gene dominates, the cross breed chicken (BW) is speckled. This is called blue.”

2) Copy out the genetic square below and say how many black, white and speckled (blue) chicks are

expected.

3) a) Draw out a genetic square to show the next generation of chickens, when two blues breed.

b) How many chicks of each colour would you expect?

Humans4) Copy the following information:

“The genes for brown-eyed children (B) are dominant (stronger). The genes for blue-eyed children (b) are recessive (weaker).”

30

5) Copy the genetic square, filling in the genes carried by the sperm.

6) How many brown eyed children could you expect?7) How many blue eyed children could you expect?8) Which genes did the father pass on in his sperm?9) What was the father’s gene combination (genotype)?

Extension

A boy has two rabbits. The male is grey and the female is white. On mating, all the baby rabbits were grey. When the grey baby rabbits had grown, he let two of them mate several times. One quarter of the babies turned out to be white.

1) Which coat colour was dominant?2) Explain why the first two rabbits, shown in fig A, did

not have any white babies?3) Explain why the grey offspring were able to have

white babies (fig. B).4) White babies are more

popular and fetch a higher price. Suggest how the boy could arrange mating so that only white babies were produced. Show how you worked it out by using genetic squares.

Homework Four – Playing God?

31

Scientists are always trying to make improvements to the world we live in. Farmers want to reduce their costs to obtain greater profits. One way to improve the animals and plants so they more fulfil the needs of humans is to selectively breed in features that are required.

1) If you were a scientist, what two fruits would you select features from to try to make a new fruit which you would prefer?

2) Draw the two fruits you have selected.3) What features would you like to keep from these two

fruits?4) What features would you like to breed out of the two

fruits?5) Draw a picture of the new fruit, labelling all the

features you have kept and why.6) Give your fruit a name.7) What advertising slogan would you use to help to sell

your fruit?

ExtensionIn recent years there have been many debates in the media about genetic experiments. Research one of the following and, in the form of an essay, give your ideas both for and against further research in this area.

1) The breeding of genetically modified plants which contain genes that produce specific pesticides to prevent damage by pests.

2) Breeding animals that produce enzymes and chemicals which are useful for humans (e.g. a pig that can produce insulin for treatment of diabetics).

3) Breeding animals that carry organs that can be transplanted into humans (e.g. a pig with a liver that can then be transplanted into a person with a terminal liver problems)

4) The cloning of humans as a source of organs for people with damaged or diseased organs.

5) The splicing of chromosomes to enable parents to choose particular features for their child to carry, such as eye colour and intelligence.

32

Chemical Reactions

Homework One - Conservation of mass

Six groups of students were given different amounts of magnesium with which to make magnesium chloride. Each group measured how much magnesium chloride they had made. These are the results they obtained:

Group Mass of magnesium used

(g)

Mass of magnesium

chloride made (g)A 1 4B 5 20C 20 80D 7 36E 10 40F 20 80

1) Label the axes of your graph like this:Plot a scatter graph of their results. Draw a line of best fit.

Mass ofmagnesiumchloride (g)

Mass of magnesium (g)

33

Using the information in the graph, answer these questions:

2) Which pattern do most of the results show?3) Which result does not fit this pattern? Circle it on

your graph.4) Predict from your graph

(i) How much magnesium chloride would be produced if a student started out with 15 g of magnesium?

(ii) How much magnesium would be required to make 44g of magnesium oxide?

Homework Two – Chemical ChangesAt 7 am Mr Meldrew staggered out of bed and into the bathroom. He cleaned his teeth, using toothpaste to neutralise the plaque acid. He went downstairs, struck a match and lit the gas. He put on

the kettle and whilst waiting for it to boil he went to the fridge. Mr Meldrew was annoyed to find that the milk had gone sour so decided to do without it. When the water had boiled he brewed his tea using hot water to dissolve out the chemicals from the tea. Some bacon in the fridge smelt a little strange. He thought the bacteria had acted on it, but decided to cook it anyway.

When he got to his car it wouldn’t start. Opening the bonnet he noticed lots of rust around the battery and a loose terminal. On tightening this up he got grease on his shirt, but at least he managed to get the car to start and drove off to work.

He got home to find he had used too much yeast to ferment his wine. The container had exploded throwing wine over everything. He put the stained clothes in bleach to soak. He now began to feel stomach pains from eating the bacon that morning. He dissolved some stomach powder in water, drank it and left it to work on his stomach acid. He was so tired he fell asleep by the fire, and the chocolate in his pocket melted. As it ran down his

34

leg he moaned ‘I can’t believe it! Sour milk, a faulty car, exploding wine, and a bad stomach. What a day!!!’.

1) Make a table of what happened to Mr Meldrew. For each event state whether it was a chemical or physical change.

What happened Chemical or physicalCleaning teeth Chemical

2) For each event explain why it is a chemical or physical change. If it is a chemical change describe what has happened in as much detail as you can (e.g. brushing teeth is a chemical change because the bacteria in the mouth produce acid which attacks teeth. The acid is neutralised by the toothpaste making it harmless).

Homework Three – Making salts

Acids react with bases to make salt and water. The following equation shows what happens when sulphuric acid reacts with copper oxide.

Sulphuric acid + Copper oxide Copper sulphate + Water

1) Write down the name of the chemical which is a base.

2) Write down the name of the chemical which is a salt.3) What name is given to a reaction where an acid is

used up by a base?4) Complete the following word equation:

Nitric acid + Zinc oxide _ _ _ _ _ _ _ _ _ _ + _ _ _ _ _

If acids are reacted with some metals, hydrogen is made instead of water. A salt is still produced.

35

5) Complete the following word equations:

Magnesium + Sulphuric acid __ _ _ _ _ _ _ _ _ _ _ _ _ _ + _ _ _ _ _ _ _ _

Iron + Hydrochloric acid __ _ _ _ _ _ _ _ _ + _ _ _ _ _ _

6) Name a metal that does not react with an acid to produce hydrogen.

7) Name a metal which would be explosive if put into any acid.

8) What is the difference between an alkali and a base?

Extension

Homework three – What’s the reaction?This is a list of common types of chemical reactions:

1) Copy out the below table, putting the correct word from the list above next to its meaning.

Word MeaningThis is a reaction that takes in heat – it gets colderA reaction that gives out heat – it gets hotterThis occurs when something burns in oxygen.When an acid and a base cancel each other outThe conversion of food and oxygen into energy. It

36

When we burn certain fuels, we produce some poisonous gases. When these gases meet the clouds, they form acid rain. Find out using the library or Encarta:

· Which fuels give off gases that can lead to acid rain.

· How we can reduce the emission of such gases.

· The long term effects on forests, wildlife and the oceans.Use this information, write a five minute assembly to be used on your year group discussing the affects that our current life style has on the environment.

Respiration Exothermic Oxidation Fermentation Reduction Neutralisation Rusting PhotosynthesisCombustion Endothermic

occurs inside our bodies.The reaction of iron with oxygen and water.The gain of oxygen by a chemicalThe loss of oxygen from a chemicalThe turning of sugar into alcohol.Plants use the sun’s energy to make their food.

2) Using the work you have already done, give an example for each of the above types of reaction. Write it in the form of a word equation.

3) Try to write chemical equations for each of the examples you have been given. You can use your copy of the periodic table to help with the symbols.

Particles

Homework One – States of Matter

Look at these particle pictures. They represent a solid, a liquid and a gas.

Now look at this picture and explanation of a solid dissolving in a liquid.

The particles in a solid are close together. The particles in a liquid are more spread out and moving quickly. When they bash into the solid, they break solid particles off. Eventually they become totally mixed.

37

1) Now draw particle diagrams and give full explanations for each for each of the following:

a) A solid expanding.b) A solid melting.c) A gas condensing.d) A liquid freezing.e) Two gases diffusing.

Extension

1) Draw each of the above boxes. Underneath each one, put the label that best describes the contents of the box from below (extra – give your own example of chemicals that fit the criteria).

Homework Two – Melting and Boiling Points

The melting point of a substance is the temperature at which it turns from a solid to a liquid. The boiling point of a substance is the temperature at which it turns from a liquid to a gas.

The latent heat of vaporisation is the amount of energy needed to turn a substance from a liquid to a gas.

38

Atoms of a mixture

A mixture of compounds

Molecules of a compound

Molecules of an element

Atoms of an element

This energy is used to break the attraction between the liquid particles.

Substance Melting point (oC)

Boiling point (oC)

Latent heat of

vaporisation (kJ per Kg)

Aluminium 660 2467 10900Helium -270 -269 20.7Copper 1083 2595 4760Iron 1537 2927 6270Water 0 100 2260Ethanol (alcohol)

-117 79 838

Oxygen -218 183 213Nitrogen -210 -196 199

1) Use the table to answer these questions in full sentences.

a) What is the melting point of ice?b) What is the boiling point of water?c) Which substance has the highest melting point?d) Which substance has the lowest boiling point?e) Will iron be a solid or a liquid at 1500 oC?f) Which of the substances are liquid at room

temperature (20 oC)?g) If a mixture of ethanol and water is heated,

which will boil first?h) If a liquid mixture of oxygen and nitrogen at -

205 oC is slowly warmed, which will be the first to boil away?

i) If the substances were cooled down from room temperature, which would remain a gas for the longest time?

j) Having reached its boiling point, which substance requires the most energy to turn it into a gas? What does this tell you about the attraction between its particles?

Extension

39

1) Draw the apparatus you would use to separate alcohol from water. Describe how it works.

Homework Three – Melting and Cooling Curves

Imagine a beaker of pure ice with a thermometer in it. You heat the ice with a Bunsen Burner. As the temperature increases, the ice molecules vibrate faster and faster. The kinetic energy of the molecules increases.

Eventually, the molecules have so much energy they can break away from each other. They separate and move freely. The solid melts and turns into a liquid.While the melting is happening the temperature does not rise. The energy you are putting in is used to break the connection between the molecules.

Once all the solid has become a liquid then the temperature starts to rise. It will continue to rise until the liquid begins to boil. The liquid water becomes a gas. While the water is boiling the temperature stays the same. The energy is used to break the attraction between the liquid molecules. This energy is called latent heat.

A gas can lose energy and change to become a liquid – called condensation.

A liquid can lose energy and change state to become a solid – called freezing.

1) The graph below shows what happens when ice is heated until it boils. Use the information above to label the parts of the heating curve for water.

Labels to use:Ice meltingWater boilingWater gets hotterIce starts to meltWater starts to boilAll ice turned to water

2) Use the information in the passage above to label the parts of the cooling curve for water.

40

Labels to use:Water freezingSteam condensingAll steam turned to waterWater cools down

41

Homework Four – Solutions, Solutes and Solvents

1) Copy out the following table. Put in the correct word from the list below.

This is a mixture of a two substances where the particles are totally mixed up.This is the substance which does the dissolving.

This is the substance which is dissolved.

This is a substance which can be dissolved in the solvent.

Word List

2) When you add sugar to water you make a solution.a) What is the solute in this example?b) What is the solvent in this example?

3) In a bottle of coke there are many substances. Most of it is made from water and a gas called carbon dioxide (this gives the fizz).a) What is the solute in this example (the water or the

gas)?b) What is the solvent in this example (the water or the

gas)?4) Oil is insoluble in water. What does insoluble mean?5) When we wash clothes that have oil on them, the stain

will not come out with water. What do we need to add to help dissolve the oil?

Extension

Different substances have different solubilities in water.1) a) What does the word solubility mean?

b) Two solids are totally mixed up. One is very soluble in water, the other is only partially soluble in water. We

42

soluble solution solute solvent

could separate these two substances using Chromatography. Explain what ‘chromatography’ is and how you would carry it out.

Electricity, Magnetism and Energy.

Homework One – Drawing Circuits

1) Copy out this table and then add in the symbols which are commonly used in electrical circuits:

The electrical component The symbolA bulbA switchA battery made up of 3 cellsA cellA power supplyA variable resistorAn ammeterA voltmeter

2) Using the symbols you have just drawn, carefully draw in pencil (using a ruler) the following circuits:a) A series circuit with one cell and one bulb.b) A series circuit containing a 3 volt battery (remember

each cell provides 1.5 volts), two bulbs and a switch to turn off both bulbs.

c) A series circuit containing 3 bulbs and a device for dimming the lights.

3) Copy out the following table and then complete it.

Action in series circuit

Result of action Explanation of why this happens.

What happens to the brightness of the bulbs when I add another bulb?What happens to the other bulbs when I

43

unscrew one bulb from its holder.

Extension

Ann set up some circuits to look at the relationship between current flowing through an electrical component and the voltage across it. Each of her bulbs has a resistance of 1 ohm (). Here are her results.

Voltage (volts) Number of bulbs in series

Current (amps)

1 1 12 1 23 12 14 2

2 2.56 3 23 3

The equation for voltage is:

Voltage = current x total resistance

4) Copy the equation you were given for how to work out the voltage.

5) Now, rearrange the equation so you can a) Calculate the current.b) Calculate the resistance.

6) Copy the table into your book and fill in the missing spaces.

7) Using the symbols you have drawn above, draw the circuit you would use to get the readings for 2 bulbs in series.

Homework Two - Series and Parallel Circuits

1) Copy out the following table and fill in the spaces.

44

Action in parallel circuit

Result of action Explanation of why this happens.

What happens to the other bulbs when I unscrew a bulb from one branch? What happens to the brightness of the bulbs when I add another bulb in a new branch?

2) Draw out proper circuit diagrams (using rulers and pencil) for each of the following. The first has been done for you.

3) By each of your circuits, write down the word series or parallel.

4) On each of your circuits, draw an ‘X’ by the bulb which has an X on in the diagram.

5) For each circuit, describe what would happen to the other bulbs when bulb X is unscrewed.

45

6) In the following diagram, three bulbs are connected in a circuit, but you can’t see the connections. Lamp A is brighter than B and C. When A is removed, B and C are not affected. When C is removed, B goes out but A shines on.

a) Which two lamps are connected in series?b) Which of the lamps is in parallel to the other two?c) Draw the circuit.

Extension

1) Draw the following circuits using the normal symbols. a) A parallel circuit with one cell, an ammeter

measuring the current, two bulbs in parallel and a switch that can turn only the second bulb off.

b) A parallel circuit with a 4.5 V battery, three bulbs in parallel and a switch that can turn only two of the bulbs on or off together.

c) A circuit is built which has two cells connected to give 3 V. Three bulbs are connected to the cells so that each one is as bright as it can be. A voltmeter is connected across each bulb. The circuit has one switch that can turn off all three bulbs.

d) A 4.5V battery and four bulbs are connected so each one does not light up very brightly. An ammeter is connected so that it can measure the current flowing through the circuit.

e) A power pack set on 2V is connected to two bulbs connected in parallel. There is a switch in the circuit. When the switch is ‘open’ the bulbs light up quite brightly, but when the switch is ‘closed’ the bulbs go out.

Homework Three – Changing Electrical Energy Into Other Forms

46

1) Copy the following table and fill in the cells on the right hand side with the names of devices that will transform energy as indicated on the left hand side. The first one is done for you.

Energy Transformation DeviceElectrical to light Light bulb

Electrical to movementElectrical to soundElectrical to heat

Electrical to chemicalChemical to electrical

Movement to electrical

2) A student put two strips of clean lead into a beaker of sulphuric acid. She connected a power supply and ammeter to charge up her lead acid cell and charged it at 1 Amp for 5 minutes. She connected it to a bulb and noticed that the bulb was kept lit for 20 seconds. She repeated the process charging the cell up for longer and longer periods, measuring how long the bulb was lit for each time. Her results are shown below:

Time the cell was charged for (min)

Time the bulb was lit (seconds)

5 2010 4015 6020 8025 9430 9835 98

3) Plot a graph with “Time the bulb was lit” up the side and “Time the cell was charged for” along the bottom then answer the following questions:

4) Electrical energy is supplied to the lead acid cell. What form of energy is it transformed to?

5) Up to a charging time of 20 minutes how does the amount of energy stored change with charging time?

47

6) After 25 minutes how does the amount of energy stored change with charging time?

7) Can you explain this behaviour?

Homework Four – Voltage and Ohm’s Law

1) Copy the following diagrams and write in the readings on the meters.

D

48

Diagram 2

Diagram 1

Ohm’s law tells us how electrical resistance, measured in Ohms (), is related to the voltage, in Volts (V), and the current, in Amps (A).

a) Resistance () = voltage (V)/current (A)

2) Copy the following table and use Ohm’s law to calculate the values needed to complete it:

Resistance () Voltage (V) Current (A)10 212 421 3

4 208 165 5

Extension

The voltage (V) across a device tells us the amount of electrical energy, in Joules (J) that is transformed for each Coulomb (C) of charge that flows through it. The total energy transformed is given by the following equation:

Total energy (J) = Voltage (V) x Charge (C)

1) Copy the following table and use the above equation to calculate the values needed to complete it:

Total Energy (J) Voltage (V) Charge (C)6 212 412 0.51 0.2

8 26 3

49

Using forces

Homework One - Moving At Speed

The speed triangle can be used to work out speed using the following equation:Speed = distance

time1) Copy the speed triangle into your book. Now write out

the equations you need to use to work outa) the time andb) the distance.

2) Copy out this table and use the speed triangle to fill in the blanks. Make sure you include the correct units.

Distance travelled

Time taken Average speed

A walker 12 km 3 hrA jogger 3 km 30 minA marathon runner

2 hr 22 km/hr

A sprinter 100m 10 m/s

You must show all your working out for the following questions, including any equations you are using.

3) A bird flies at 28 m in 4 seconds. What is its speed?4) How far would the bird have flown after 60 seconds?5) There are 86400 seconds in a day. How far in metres

would the bird fly in one day?6) How far in kilometres would the bird have flown in a

day?7) The distance from Belper to South Africa is 10,000 Km.

How many days would it take the bird to fly there without resting?

8) If there is a following wind of 4 km/hr, would the bird now be travelling faster or slower? Use a diagram to explain what you mean.

9) How fast would the bird now be travelling.

50

10) How long would it now take the bird to get to its nesting site in South Africa?

ExtensionThis table shows the overall stopping distance at different car speeds.

Speed of car (m/s) 10 15 20 25 30Thinking distance (m)

6 9 15 18

Braking distance (m)

8 18 50 72

Overall stopping distance (m)

14 27 65 90

Stopping distance = the thinking distance + the braking distance.

1) What do you think is meant by the term thinking distance?

2) How does the thinking distance depend on the speed of the car?

3) What thinking distance corresponds to a speed of 20 m/s?

4) Giving your reasons, suggest the minimum distance that a car should be driven behind another, if both are travelling at 15 m/s.

5) How do you think the thinking distance is affected by the

condition of the road (if it is dry or icy)?6) How do you think the braking distance is affected by

the condition of the road?

7) A car travelling at 25 m/s on a wet road now has an overall stopping distance of 105 m. What is the driver’s

a) thinking distance b) braking distance?8) Why is the braking distance greater on wet roads?

Homework Two - Moments

The diagrams on the following page show planks of wood resting on a pivot in the middle. The planks have

51

weights on them. All the weights are identical. There are three possibilities:

A – the plank balancesB – the right-hand side goes

downC – the left hand side goes

down.

For each of the 8 planks, work out the moment on each side. Using this, write down what will happen in each case (A, B or C). You must show all your working out. An example is given.

Example:

Moment = force x distanceLeft moment = 4N x 3m = 12Nm Right moment = 3N x 5m = 15NmThe right hand side moment is greater. The plank will tilt to the right. Therefore the answer is B.

52

1) Now try these: (Remember to show your working out).

2) In which diagram is there least force on the pivot? (explain your answer).

3) In which diagram is there most force on the pivot?

Extension

This picture shows how a person can balance out the weight of an elephant using a long lever.

53

1) Make a sketch of this diagram in your book. Add the labels:

effort, lever, pivot and load.2) Now copy each of the following diagrams into your

book. On each diagram:a) Label the pivot and colour it in green.b) Draw a red arrow to show where you would have to

push or pull to make it work. Label this arrow effort.c) Now draw a blue arrow to show where the machine

pushes or pulls. Label this arrow load.

d) Now label each lever as a force-magnifier or a distance magnifier

Homework Three - Pressure

The pressure triangle can be used to work out pressure

54

using the following equation:Pressure = force

Area

1) What happens to the pressure if the force is doubled?2) What happens to the pressure if the area over which it

is applied is doubled?3) Using the formula above work out the unit for pressure.

(The unit for force is Newton’s and the unit for area is square centimetres).

4) Here is a picture of a design for a water pistil. Use it to answer the following questions:a) If the nozzle is closed, what

happens to the pressure inside the gun when twice the force is applied?

b) When the nozzle is open, a small jet of water shoots a long way. Using the following words try to explain why this happens:

Force small area pressure large area

c) What two ways could you make the jet of water travel further.

d) A force of 10 Newtons is applied to the trigger. The piston has a surface area of 10 cm2. Use the equation at the top of the page to work out the pressure inside the chamber. Don’t forget to show all your working and use the units.

e) The nozzle has a surface area of 1 cm2. At what pressure does the water leave the nozzle.

5) a) What is it about snow shoes that prevents us from sinking into soft snow?b) When a skier falls, she uses the edge of the ski to

help her stand up. Try to explain why this works (think about pressure).

Extension 1) The picture below shows a hydraulic system. A small

force (effort) is applied causing a much larger force,

55

allowing the load to move. Using the labels, explain in detail how this hydraulic system works.

Homework Four - Revision

1) Using a sheet of A4 paper, design a poster that would be suitable to introduce the ‘using forces’ topic to a group of Year 7 students. You need to explain what at least two of the following are and how they are used:

moments balancing forces levers centre of

gravitypressure

Use pictures or cartoons to make it interesting and to help your explanation.

2) You must also set a homework question which uses one or more of the formula you have studied. Include the answer (with all the working out) on the back of your poster.

Gravity and Space

Homework One - Weight and gravity

56

We can calculate an objects weight by using the following formula:

Weight = mass x gravity

The force of gravity on the Earth is 10 N/kg.1) Use this information to copy and complete the table

below.

Object Mass WeightA student 70 kgA car 10,000 NA feather 1gAn apple 100g

2) The force of gravity on the moon is about 6 times less than the force of gravity on the Earth. What would be the weight of the student and the apple on the moon?

57

Extension

Sir Isaac Newton is credited with having ‘discovered’ gravity. Imagine that he was alive today and had just announced his discovery.

1) Write a newspaper article reporting this to the world. What would the headline be?

Homework Two - The Sun, Moon and Earth

The sun has many effects on the earth, including causing the day and night, as well as the seasons.1) How many hours are there in a day?2) What does this length of time does it take for the Earth

to rotate once on its own axis?3) When it is daytime in England, it is night time in

Australia.a) Draw a picture of the Sun and the Earth to show

why this is the case.b) Draw another picture to show why, when it is

midday in England, it is evening in India and morning on America. Label your diagram fully, showing which way the Earth is spinning.

4) Why is it colder in winter and warmer in summer? Draw a diagram to explain this.

Extension1) Why do we have more daylight in England during the

summer than in the winter? (again a diagram may help)2) Explain why when it is midsummer in England, in the

south of Africa it is midwinter.

Homework Three - The Moon and the Earth

1) Copy and complete the following passage (using the word bank).

‘The Earth rotates around it’s own ………… every 24 ……… This length of time is called a ……… The moon is

58

…………. than the Earth, but still has an affect on the Earth’s ………. It ……….. the Earth every 28 days. The moon itself doesn’t produce ……….. We can only see it because it reflects light from the ………..’

Word List:

2) Below is a diagram showing the moon orbiting the Earth. Copy the diagram but on each picture of the moon, draw the shape you would expect to see in the sky.

Extension

3) What is a lunar eclipse? Draw a labelled diagram to help your explanation.

4) What is a solar eclipse? Draw a labelled diagram to help your explanation.

Homework Four - Our Solar System1) Name the nine planets in our solar system.2) Write out a rhyme that is used to remember the order

of the planets.3) Which planet is

59

days hours sun light tides axisorbits smaller

a) closest to the sun?b) furthest away from the sun?c) the biggest?d) has a huge red spot, which is a large storm?e) has an elliptical orbit?

4) Between which two planets is the asteroid belt located?5) How many days does the Earth take to orbit the sun?

What do we call this length of time?6) Which planet makes the largest orbit? What effect does

this have on the length of its ‘year’?

ExtensionLook at the data below:

Planet Relative diameter

Period of orbit (years)

Number of moons

Mercury 0.4 0.2 0Venus 0.9 0.6 0Earth 1.0 1.0 1Mars 0.5 1.9 2

Jupiter 11.2 11.9 16Saturn 9.4 29.5 15Uranus 3.8 84.0 5

Neptune 3.9 164.8 2Pluto 0.3 247.7 1

1) Which planet has the most moons?2) What trend do you notice about the length of orbit for

the planets?3) Which planet do you think has the greatest gravity?

Explain why.

Homework Five - Our Universe

1) Copy out the following sentences putting true or false at the end of each depending on what you think.

a) A universe is a collection of solar systems (true or false)?

b) A solar system is the same as a galaxy (true or false)?

c) The stars we see in the sky are suns (true or false)?

60

d) The sun is a star (true or false)?e) Andromeda is the name of a galaxy (true or false)?

2) Put the following in order of size (largest first):

Star Universe Moon Galaxy Asteroid Planet Solar system

Extension

1) Explain what the ‘Big Bang’ theory is (use the library).2) What will eventually happen to our sun (look this up)?

61