Crown Hills Community College
Year 8
Science Homework
Name ________________________ Form ________
Teacher ______________________ Room ________
Year 8 – Science Homework
Content
Page Title Date set Due date Completed 1 Forces keywords 2 Forces extended question 3 Matter keywords 4 Matter extended question 5 Organisms keywords 6 Organisms extended question 7 Electromagnets keywords 8 Electromagnets extended question 9 Waves keywords 10 Waves extended question 11 Ecosystems keywords 12 Ecosystems extended question 13 Reactions keywords 14 Reactions extended question 15 Energy keywords 16 Energy extended question 17 Earth keywords 18 Earth extended question 19 Genes keywords 20 Genes extended question 21 Wind turbine variables 22 Solar panel variables 23 Variables 24 Washing powder experiment 25 Modified plants experiment 26 Spring extension variables 27 Photosynthesis graph 28 Hydrocarbon graph 29 Limestone experiment 30 Line and bar graphs 31 Carbon dioxide graph 32 pH graph 33 Temperature graph 34 Oxygen bubbles experiment
35-36 Hair dye experiment 37-38 Pollen grain experiment
Year 8 – Science Homework Forces keywords
Name: _____________________ Form: _________ Completed on time
moment
Single force which can replace all the forces acting on an object and have the
same effect.
resultant force
A measure of the ability of a force to
rotate an object about a pivot.
drag force
The point beyond which a spring will not return to its original length when the
force is removed.
law of moments
Force extending or pulling apart.
elastic limit
The force acting on an object moving through air or water that causes it to
slow down.
tension
An object is in equilibrium if the clockwise moments equal the
anticlockwise moments.
pressure
Force squashing or pushing together, which changes the shape of an object.
compression
The ratio of force to surface area, in N/m2, and how it causes stresses in
solids.
1.
Year 8 – Science Homework
Forces extended question
Two students are trying to explain how a chair cushion supports your weight. One student says the seat just squashes the same amount whoever sits on it and the other says it depends on how heavy the person is.
The diagram shows the inside of a chair cushion.
Explain how a chair cushion supports your weight and which student is correct. In your answer you should include diagrams to show the forces on the springs as someone is sitting down and when they are sitting still.
(6 marks)
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Name: _____________________ Form: _________ Completed on time
Teacher: _______________________________________ Effort Grade
Merits awarded
2.
Year 8 – Science Homework
Forces extended question
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Year 8 – Science Homework Matter keywords
Name: _____________________ Form: _________ Completed on time
atom A one- or two-letter code for an element
that is used by scientists in all countries.
chemical formula A substance made up of atoms of two
or more elements, strongly joined together.
chemical symbol A group of two or more atoms, strongly
joined together.
compound A formula that shows the relative
number of atoms of each element in a compound.
element A table of all the elements, in which elements with similar properties are
grouped together.
molecule A substance that cannot be broken
down into other substances.
Periodic Table A molecule made by joining up
thousands of smaller molecules in a repeating pattern. These can be natural
or synthetic.
polymer The smallest part of an element that
can exist.
3.
Year 8 – Science Homework
Matter extended question
Describe the chemical reactions of Group 1 and Group 7 elements.
Your answer should include: examples of word equations for a specific Group 1 element the reaction between a Group 7 element and iron word equations for any reactions you describe. (6 marks)
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Name: _____________________ Form: _________ Completed on time
Teacher: _______________________________________ Effort Grade
Merits awarded
4.
Year 8 – Science Homework
Matter extended question
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Year 8 – Science Homework organisms keywords
Name: _____________________ Form: _________ Completed on time
addiction The transfer of gases between an organism and its environment.
bile A drug that slows down the body’s
reactions by slowing down the nervous system.
deficiency A lack of minerals, that causes
poor growth.
gas exchange A need to keep taking a drug in order to
feel normal.
drug Enzyme that breaks down lipids into
fatty acids and glycerol.
alcohol Substance that breaks fat into
small droplets.
respiratory system Chemical substance that affects the
way your body works.
lipase The organs involved in gas exchange.
5.
Year 8 – Science Homework
Organisms extended question
Describe the main events that take place inside your body in order to turn a meal into simple food molecules. (6 marks)
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Name: _____________________ Form: _________ Completed on time
Teacher: _______________________________________ Effort Grade
Merits awarded
6.
Year 8 – Science Homework
Organisms extended question
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Year 8 – Science Homework Electromagnets keywords
Name: _____________________ Form: _________ Completed on time
magnet
A region in which there is a force on a
magnet or magnetic material.
magnetic pole
A device that uses an electromagnet to make sound from a varying potential
difference. Turns an electrical signal into a pressure wave of sound.
magnetic field
A material with a magnetic field around it in which a magnetic material
experiences a force.
solenoid
A device that uses an electromagnet
to break a circuit if the current is too big.
core
Wire wound into a tight coil, part of an
electromagnet.
electromagnet
A non-permanent magnet turned on and off by controlling the current
through it.
loudspeaker
The ends of a magnetic field, called
north-seeking and south-seeking poles.
circuit breaker
Soft iron metal which the solenoid is
wrapped around.
7.
Year 8 – Science Homework
Electromagnets extended question
Describe how you would investigate how the number of coils affects the strength of an electromagnet, using this equipment:
iron core; wire; power supply; paper clips (small, medium, or large)
Your answer should include:
a method
how you control the variables
whether you should repeat
whether you should use small, medium, or large paper clips
safety advice. (6 marks)
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Name: _____________________ Form: _________ Completed on time
Teacher: _______________________________________ Effort Grade
Merits awarded
8.
Year 8 – Science Homework
Electromagnets extended question
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Year 8 – Science Homework Waves keywords
Name: _____________________ Form: _________ Completed on time
electromagnetic spectrum
The part of a longitudinal wave where
the air particles are close together.
gamma ray
When waves join together so that they
add up or cancel out.
compression
Waves with the lowest frequency in the electromagnetic spectrum, used
for communicating.
transverse wave
A wave in which the direction of vibration is the same as that of the
wave.
longitudinal wave
The range of wavelengths of radiation produced by the Sun and
other sources.
superpose
Wave of the electromagnetic spectrum used for producing images of bones
and tissue.
radio waves
Wave with the highest frequency in the
electromagnetic spectrum.
X-ray
A wave in which the direction of vibration is perpendicular to that of the
wave.
9.
Year 8 – Science Homework
Waves extended question
Microwaves have a frequency range of 300 million Hz to 300 000 million Hz.
They are used both for mobile phones and for cooking food.
In microwave ovens, the microwaves are absorbed by water in food, causing it to warm up. The frequency of microwaves used in ovens is 2500 million Hz.
Mobile phones send and receive use microwaves for communication. These microwaves are not absorbed by water, but they do cause a very small heating effect.
Living cells contain water.
Explain why microwaves from ovens are dangerous but microwaves from mobile phones are thought to be safe for you to use.
Suggest some precautions you should take with your mobile phone. (6 marks)
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Name: _____________________ Form: _________ Completed on time
Teacher: _______________________________________ Effort Grade
Merits awarded
10.
Year 8 – Science Homework
Waves extended question
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Year 8 – Science Homework Ecosystems keywords
Name: _____________________ Form: _________ Completed on time
aerobic respiration The substance in blood that carries oxygen around the body.
anaerobic respiration Chemical reaction where glucose reacts with oxygen to release energy, carbon
dioxide, and water.
haemoglobin A lack of minerals, that causes
poor growth.
oxygen debt Chemical containing minerals, normally
applied to soil.
deficiency Extra oxygen required after anaerobic respiration to break down lactic acid.
fermentation Chemical reaction that takes place
without oxygen. Glucose is converted into lactic acid and energy is released.
fertiliser Green pigment in plants and algae which absorbs light energy.
chlorophyll Chemical reaction used by
microorganisms to convert glucose into ethanol, carbon dioxide, and energy.
11.
Year 8 – Science Homework
Ecosystems extended question
Explain, in detail, how plants are adapted for photosynthesis. (6 marks)
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Name: _____________________ Form: _________ Completed on time
Teacher: _______________________________________ Effort Grade
Merits awarded
12.
Year 8 – Science Homework
Ecosystems extended question
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Year 8 – Science Homework Reactions keywords
Name: _____________________ Form: _________ Completed on time
conservation of mass A chemical reaction in which a
compound breaks down to form simpler compounds and/or elements.
combustion A chemical reaction in which
substances react with oxygen to form oxides.
decomposition A substance that stores energy in a
chemical store which it can release as heat.
exothermic In a chemical reaction, the
total mass of reactants is equal to the total mass of products.
oxidation A reaction that takes in energy, usually
as heat. In other words, it transfers energy from the surroundings.
physical change A chemical reaction in which a
substance reacts quickly with oxygen and gives out light and heat.
fuel A change that is reversible, in which new substances are not made. Examples of physical changes include changes of
state, and dissolving.
endothermic A reaction that gives out energy, usually as heat or light. In other words, it transfers
energy to the surroundings.
13.
Year 8 – Science Homework
Reactions extended question
Look at these energy-level diagrams for melting and freezing.
Identify which graph shows which process.
Explain what each graph shows about how heat is being transferred in the reaction, and explain what is happening in terms of bond breaking and/or bond making. (6 marks)
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Name: _____________________ Form: _________ Completed on time
Teacher: _______________________________________ Effort Grade
Merits awarded
14.
Year 8 – Science Homework
Reactions extended question
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Year 8 – Science Homework Energy keywords
Name: _____________________ Form: _________ Completed on time
conduction
The transfer of energy as a wave.
convection
A type of machine which is a rigid bar
that pivots about a point.
radiation
The store containing energy due to the vibration or movement of
particles of a substance.
lever
Transfer of thermal energy when
particles in a heated fluid rise.
pulley
Transfer of thermal energy by the
vibration of particles.
thermal energy store
Radiation given off by the Sun and other objects that brings about
energy transfer.
(thermal) insulator
Material that only allows heat to
travel slowly through it.
infrared (radiation)
A system to lift (or lower) heavy objects.
15.
Year 8 – Science Homework
Energy extended question
The diagram shows a section of roof insulation. The material consists of a layer of foil and a layer of foam on a wooden board.
Explain how the material has been designed to reduce the transfer of thermal energy by conduction, convection, and radiation.
Your answer should include:
description of thermal energy transfers
descriptions of how thermal energy transfer can be reduced.
(6 marks)
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Name: _____________________ Form: _________ Completed on time
Teacher: _______________________________________ Effort Grade
Merits awarded
16.
Year 8 – Science Homework
Energy extended question
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Year 8 – Science Homework Earth keywords
Name: _____________________ Form: _________ Completed on time
atmosphere
The gradual increase in the average surface temperature of the Earth.
greenhouse gases
Summarises how carbon and its compounds enter and leave the
atmosphere.
global warming
The mixture of gases surrounding the
Earth.
carbon cycle
A gas that contributes to the greenhouse
effect, such as carbon dioxide.
minerals
Using electricity to split up a compound
into its elements.
ore
Collecting and processing a material so that
it can be used again.
electrolysis
Chemicals that rocks are made from.
recycling
A naturally occurring rock that contains enough of a mineral to make it worth getting the
mineral – and then the metal it includes – out of the rock.
17.
Year 8 – Science Homework
Earth extended question
Describe the sources of human-produced global warming. Suggest ways in which changes in human behaviour may reduce global warming and the consumption of natural resources. (6 marks)
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Name: _____________________ Form: _________ Completed on time
Teacher: _______________________________________ Effort Grade
Merits awarded
18
Year 8 – Science Homework
Earth extended question
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Year 8 – Science Homework Genes keywords
Name: _____________________ Form: _________ Completed on time
chromosome A technique in which scientists
insert foreign genes into organisms to change their characteristics.
genetic modification Section of DNA that contains the information for a characteristic.
allele Long strand of DNA, which contains
many genes.
DNA Process by which the organisms with the characteristics that are most suited to the
environment survive and reproduce, passing on their genes.
gene Different forms of a gene.
mutation When no more individuals of a species remain anywhere in the world.
natural selection Change to DNA that can cause
disease.
extinct Chemical that contains all the information needed to make
an organism.
19.
Year 8 – Science Homework
Genes extended question
Explain how a lack of biodiversity can affect an ecosystem and why helping to preserve biodiversity can benefit humans. (6 marks)
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Name: _____________________ Form: _________ Completed on time
Teacher: _______________________________________ Effort Grade
Merits awarded
20.
Year 8 – Science Homework
Genes extended question
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Year 8 – Science Homework
Wind turbine variables
What was the independent variable in the investigation?
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What was the dependant variable in the investigation?
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State one control variable for the investigation.
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Number of blades
Name: _____________________ Form: _________ Completed on time
Teacher: _______________________________________ Effort Grade
Merits awarded Extension Task:
Research the advantages and disadvantages of using wind turbines to generate electricity.
Number of blades
21.
Year 8 – Science Homework
Wind turbine variables
Explain the advantage of taking repeat readings.
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Year 8 – Science Homework
Solar panel variables
A student was investigating how the angle of tilt of a solar panel affected the energy generated by the solar panels.
Name: _____________________ Form: _________ Completed on time
Teacher: _______________________________________ Effort Grade
Merits awarded Extension Task:
Research the advantages and disadvantages of solar panels.
22.
Year 8 – Science Homework
Solar panel variables
1. State the independent variable for the student’s investigation.
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2. State one control variable for the student’s investigation.
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3. Describe the trends shown in the table of results.
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Year 8 – Science Homework
Variables
For each of the experiments show state the independent, dependent and control variables.
Do earthworms prefer wet or dry soil?
1. You have a tub filled with soil.
2. One half is wet and the other is dry.
3. You put 10 earthworms in the tub and leave them for 1 day.
4. You count how many worms are on the dry side and how many are on the wet side.
Do bananas go brown more quickly if you keep them in the dark or in the light?
1. You have 2 bananas you bought at the same time from the same bunch.
2. You put one banana in a cupboard and the other on a windowsill.
3. You leave them for 3 days and compare bananas to see which is darker.
Name: _____________________ Form: _________ Completed on time
Teacher: _______________________________________ Effort Grade
Merits awarded Extension Task:
Invent your own experiment, state the independent, dependent and control variables
23.
Year 8 – Science Homework
Variables
Which object falls more quickly?
1. You have a fork, a hairbrush and a shoe.
2. You drop them out the window at your house
3. You time how long they take to hit the ground.
Which is the best biscuit for dunking?
1. You have 3 types of biscuit; Rich Tea, Custard Creams and Chocolate digestives.
2. You dunk each biscuit into a cup of tea
3. You time how long it takes for each biscuit to break in half.
4. The biscuit that takes the longest to break is the best for dunking.
Experiment
Independent Dependent Control
Worms
Bananas
Objects
Biscuits
Year 8 – Science Homework
Washing powder experiment
Two pupils were given a sample of ‘biological’ washing powder and a sample of ‘non biological’ washing powder.
They investigated how the two powders compare in removing egg-stains from cloth.
Plan
We put ‘biological’ powder into one bowl and ‘non-biological’ powder into the other bowl. We added water.
. We put some egg-stained cloth into each bowl.
. We left the bowls for 30 minutes. We dried out the cloth and saw what happened.
Name: _____________________ Form: _________ Completed on time
Teacher: _______________________________________ Effort Grade
Merits awarded Extension Task:
Research the difference between biological and non-biological washing powder.
24.
Year 8 – Science Homework
Washing powder experiment
Look at their report.
(a) Give one way they made their investigation fair. ____________________________________________________
1 mark
(b) Give two ways they could improve their investigation.
1 _______________________________________________________ 1 mark
2 _______________________________________________________ 1 mark
(c) What should they observe to compare the two types of washing powder?
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Year 8 – Science Homework
Modified plants experiment
Scientists at the University of Leeds have found a way to modify the genes of flowering plants. They claim that flowers from modified plants remain fresh in a vase of water for up to six months longer than flowers from unmodified plants.
Plan an investigation you could carry out in the school laboratory to test the claim that flowers from modified plants last for much longer than flowers from unmodified plants.
You will be provided with flowers from modified plants and from unmodified plants.
Name: _____________________ Form: _________ Completed on time
Teacher: _______________________________________ Effort Grade
Merits awarded Extension Task:
Research the advantages and disadvantages of genetically modified crop plants.
25.
Year 8 – Science Homework
Modified plants experiment
In your plan give:
• the one factor you will change as you carry out your investigation; (This is the independent variable.)
• the factor you will measure; (This is the dependent variable.)
• one of the factors you should control to ensure a fair test; • the time scale for the investigation.
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Year 8 – Science Homework
Spring extension variables
1. What has the student missed out from their graph?
Name: _____________________ Form: _________ Completed on time
Teacher: _______________________________________ Effort Grade
Merits awarded Extension Task:
Research “Hooke’s law”
26.
Year 8 – Science Homework
Spring extension variables
2. State the independent variable for the student’s investigation.
3. State the dependent variable for the student’s investigation.
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4. State one control variable for the student’s investigation.
Extension
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Year 8 – Science Homework
Photosynthesis graph
Name: _____________________ Form: _________ Completed on time
Teacher: _______________________________________ Effort Grade
Merits awarded Extension Task:
Research factors that can affect the rate of photosynthesis.
27.
Year 8 – Science Homework
Photosynthesis graph
Describe the trend shown in the graph.
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Year 8 – Science Homework
Hydrocarbon graph
Plot the results in the table on the graph.
Draw an appropriate line of best fit.
Name: _____________________ Form: _________ Completed on time
Teacher: _______________________________________ Effort Grade
Merits awarded Extension Task:
Research hydrocarbons.
28.
Year 8 – Science Homework
Hydrocarbon graph
One of the points is anomalous.
Draw a ring around the anomalous point on your graph.
Extension
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Year 8 – Science Homework
Limestone experiment
A student investigated what happens when limestone is heated strongly.
This is the method the student used:
• measure the mass of limestone before heating
• measure the mass of solid product after heating
• repeat the experiment three more times.
The student’s results are shown in the table below.
State one control variable for the student’s investigation
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Name: _____________________ Form: _________ Completed on time
Teacher: _______________________________________ Effort Grade
Merits awarded Extension Task:
Research the uses of limestone.
29.
Year 8 – Science Homework
Limestone experiment
Calculate the average (mean) mass lost. Show your working and don’t forget units
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Mean mass lost: _____________________
Suggest a possible reason for the student obtaining different results each time
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Year 8 – Science Homework
Line and bar graphs
Draw a graph for each of the tables below, you will need to decide whether to draw a bar chart or line graph.
Graph 1 Graph 2
Car colour Number of cars
Red 15
Black 19
Silver 10
Yellow 1
Blue 6
Time (minutes) Distance (m)
0 0
15 12
30 24
45 35
60 49
Name: _____________________ Form: _________ Completed on time
Teacher: _______________________________________ Effort Grade
Merits awarded Extension Task:
Describe the trend on each graph.
30.
Year 8 – Science Homework
Line and bar graphs
Graph 3
Extension
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Time (sec)
Temperature (oC)
0 45
45 20
90 5
135 2
180 1
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Year 8 – Science Homework
Carbon dioxide graph
Plot a graph of the student’s results on the grid below. Label the x axis and draw a line of best fit.
Time in minutes Volume of carbon dioxide collected in
cm3
0 0
1 46
2 70
3 85
4 94
5 96
6 96
7 96
Name: _____________________ Form: _________ Completed on time
Teacher: _______________________________________ Effort Grade
Merits awarded Extension Task:
Describe what an anomaly is.
31.
Year 8 – Science Homework
Carbon dioxide graph
Extension
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Year 8 - Science Homework
pH graph
Draw a line graph for the results shown.
What would be the likely pH of the solution if the pupil added a further 2 cm3 of alkali solution?
...............
volume of alkali added (cm3)
pH of resulting mixture
0.0 5.0
2.0 5.0
4.0 5.0
6.0 5.5
8.0 6.0
10.0 7.0
12.0 8.0
14.0 8.5
16.0 9.0
18.0 9.0
20.0 9.0
Name: _____________________ Form: _________ Completed on time
Teacher: _______________________________________ Effort Grade
Merits awarded Extension Task:
Research how knowledge of acids and alkalis can help treat wasp and bee stings
32.
Year 8 - Science Homework
pH graph
Extension
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Year 8 – Science Homework
Temperature graph
Draw a graph for the results.
Draw a smooth curve of best fit.
From your curve, estimate the temperature of the water after three minutes.
............°C
Time (minutes) Temperature (ºC)
0.0 20
0.5 26
1.0 31
1.5 36
2.0 41
2.5 46
3.0
3.5 57
4.0 56
4.5 58
5.0 59
Name: _____________________ Form: _________ Completed on time
Teacher: _______________________________________ Effort Grade
Merits awarded Extension Task:
Research what the “resolution “ of a scientific instrument is.
33.
Year 8 – Science Homework
Temperature graph
Extension
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Year 8 – Science Homework
Oxygen bubbles experiment
Name: _____________________ Form: _________ Completed on time
Teacher: _______________________________________ Effort Grade
Merits awarded
34.
Year 8 – Science Homework
Oxygen bubbles experiment
Explain why it is a good idea to take repeat readings for an experiment.
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Calculate the mean number of bubbles released per minute when the lamp was 40 cm
from the pondweed.
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Mean number of bubbles at 40 cm = __________________
Plot the results on a line graph.
Describe the trend shown in the graph.
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State the independent variable for the investigation
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State the dependent variable for the investigation
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Year 8 – Science Homework
Hair dye experiment
Jason wanted to find out if hair dye makes hair weaker. He used 5 hairs of equal length. He soaked each hair in a different concentration of hair dye for 15 minutes. He added masses to each hair until it broke.
Name: _____________________ Form: _________ Completed on time
Teacher: _______________________________________ Effort Grade
Merits awarded Extension Task:
List the control variables for the experiment
35.
Year 8 – Science Homework
Hair dye experiment
(a) The table below shows Jason’s results.
(i) Plot a graph of Jason’s results and draw a line of best fit.
concentration of hair dye
(%)
mass needed to break the hair
(g)
0.4 71
0.8 67
1.2 64
1.6 61
2.0 58
(ii) Use the graph to work out the mass needed to break hair soaked in water (0% hair dye).
.................... g
(b) What was the independent variable that Jason changed in this experiment?
...............................................................................................................................................
(c) What was the dependent variable that Jason measured in this experiment?
Year 8 – Science Homework
Hair dye experiment
(d) What is the relationship between the concentration of hair dye and the mass needed to break the hair?
...............................................................................................................................................
...............................................................................................................................................
(e) Jason wanted to investigate whether soaking hair in dye for different amounts of time affected the strength of the hair. Jason drew a table for his results. Add headings and units to the table below for Jason’s investigation.
........................................ (..........) ………………………………………… (..........)
Extension
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36.
Year 8 – Science Homework
Pollen grain experiment
Amy and Tom investigated how sugar affects the growth of pollen grains. They looked at pollen grains under a microscope.
Name: _____________________ Form: _________ Completed on time
Teacher: _______________________________________ Effort Grade
Merits awarded Extension Task:
Write some clear instructions for writing a good plan.
37.
Year 8 – Science Homework
Pollen grain experiment
(a) Give two ways in which Tom’s plan is better than Amy’s plan.
1 _________________________________________________________
2
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(b) In Tom’s investigation, what factor did he change (the independent variable)?
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(c) Look at Tom’s results in the table below.
concentration of sugar solution (%)
percentage of pollen grains that had started to grow (%)
0 0
5 30
10 100
15 30
20 10
25 0
He plotted five of his results on graph paper.
Year 8 – Science Homework
Pollen grain experiment
Plot the result for 20% sugar solution.
(d) Tom’s conclusion was, ‘The greater the concentration of sugar solution, the greater the percentage of pollen grains that had grown.’
Do his results support his conclusion? Tick one box.
yes no
Use the results in the graph to explain your answer. ___________________________________________________________
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38.