Year 8 Revision of SAW
Name:
( )
Homeroom:
Date:
1. The graph shows the death rates from lung cancer of people who have stopped smoking
(a)
What is the death rate for smokers?
140 per 100,000 people
b)
How does the death rate change:
(i) 2 years after stopping smoking?
Death rate decreases from 140 per 100,000 people at 0 years, to 100 per 100,000 people at
2 years.
(ii) 8 years after stopping smoking?
Death rate decreases from 140 per 100,000 people at 0 years, to 40 per 100,000 people at
8 years
(c)
How many years does it take for the death rate to drop from 100 deaths per 100,000 to
28 deaths per 100,000 people?
10 years (from 2 years to 12 years – so 12 minus 2 = 10 years)
(d) Describe how you would use the information in the graph to persuade someone who
had just stopped smoking not to start again.
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Graph does not take into account for how long they have been smoking before. Person could
have given up for 10 years, then smoke for a year and go straight back to 0 years again –
wasting all the time they have given up.
Many answers can be given for this – so long as you use information from the graph to back
up your reason it will be correct.
2. The table shows the breathing rates of 5 people, A, B, C, D and E as they walk at
different speeds.
Breathing rate (Breaths per minute)
Walking speed (km
per hour)
Person A Person B Person C Person D Person E
0
16
15
16
14
14
1
17
16
17
15
16
2
20
18
19
17
18
3
21
19
20
19
21
4
22
20
23
20
23
5
27
23
28
23
26
(a) Describe the independent and dependent variables in the experiment.
Independent variable: Walking speed
Dependent variable: Breathing rate
(b) Plot the results as 5 lines on the same graph with appropriate title, axes, labels, and units.
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(c) Describe all the control variables in the experiment.
All participants should walk at the same time and same path.
Same person to measure the time/ speed of each participant in the experiment, as different
people may have different reaction time.
Same person to measure the breathing rate of each participant in the experiment, as different
people may have different reaction time.
(d)
Calculate the mean (average) breathing rate for the five people when walking at 3 km
per hour. Show your working.
21 + 19 + 20 + 19 + 21; = 20 breaths per minute;
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(e)
What is the relationship between speed of walking and breathing rate?
As speed of walking increases, rate of breathing increases ............................................
(f)
For person A, what change in speed of walking increases the breathing rate by 10%?
From 2 km per hour to 4 km per hour .............................................................................
(g) Calculate the percentage increase in the breathing rate when person D changes from
walking at 1 km per hour to 4 km per hour. Show your working.
(g)
5 x 100;
3
15
= 33%;
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3. The table shows a person's breathing rate and the volume of each breath at rest and
during exercise.
Activity
Breathing rate
volume of each breath
/Breaths per minute
/dm3
At rest
18
0.5
During gentle exercise
22
1.4
During vigorous exercise
28
2.0
(a) Describe the independent and dependent variables in the experiment.
Independent variable: Amount of exercise
Dependent variable Breathing rate and volume of each breath
(b) Draw the graph of this experiment to show the relationship between breathing rate and
different activities with an appropriate title, axes, labels, and units
(c) Describe all the control variables in the experiment.
Same person to do the experiment
Same person to measure the breathing rate of that person.
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Length of doing gentle exercise and vigorous exercise should be the same.
Time should be given to rest.
Place of doing gentle exercise and vigorous exercise.
(d) How does exercise affect the breathing rate?
Breathing rate increases with exercise ............................................................................
(e)
Calculate the amount of air entering the lungs:
(i) at rest.
18 x 0.5;
= 9 dm3
(ii) during vigorous exercise.
28 x 2;
= 56 dm3
(f)
Air contains 20% oxygen. How much oxygen entered the lungs during gentle
exercise?
22 x 1.4 = 30.8 dm3;
30.8 x 20;
100
= 6.16 dm3
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4. The table shows the number of deaths from lung cancer in 6 different countries.
Number of deaths from lung cancer
Country
(per million of the population)
USA
130
England
90
Italy
75
Holland
60
Portugal
45
Spain
80
(a)
Draw a graph of these figures.
(b) The population of Portugal is 35 million.
Calculate the total number of deaths from lung cancer in Portugal.
(c) 45 x 35 =;
1575;
(c) In which country would you expect cigarette smoking to be the highest. Briefly state
your reason.
USA .................................................................................................................................
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5. The graph shows the effect of different amounts of alcohol on the mean reaction time of a
group of people.
0.6
0.5
0.4
Mean reaction
time
0.3
(seconds)
0.2
0.1
0
0
2
4
6
8
10
12
Units of alcohol in blood
(a) What is the normal mean reaction time?
0.2 seconds ......................................................................................................................
(b) Calculate the change in the mean reaction time when the amount of alcohol increases
from 2 to 6 units.
0.15 seconds
(c) What is the relationship between reaction time and the amount of alcohol in the blood?
increasing alcohol level increases reaction time .............................................................
.........................................................................................................................................
(d) Use the information in the graph to explain why it is dangerous to drink and drive.
alcohol slows reactions; less liable to respond quickly to dangerous situations; increased
chance of accident; ..............................................................................................................
.........................................................................................................................................
.........................................................................................................................................
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6. The table shows the daily nutrient needs of children of different ages
Mass of nutrient needed per day
Nutrient
Fat /g
Protein /g
Calcium /mg
Iron /mg
Boy aged 5 -11
66 - 85
30 - 65
700
10
Girl aged 5 -11
60 - 75
30 - 65
700
10
Boy aged 12 -16
75
80 - 100
500
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Girl aged 12 - 16
70
75 - 90
500
10
(a)
A 9 - year old boy needs 10 mg of iron per day. Calculate the percentage change in
the daily mass of iron needed when the same boy is 14 years old. Show your working
(a)
10 - 8 x 100;
10
= -(minus);
20%;
(b) The daily mass of iron needed by boys changes as they get older but the mass of iron
needed by girls does not change. Suggest and explain one reason why.
menstruation/monthly cycle in females; iron needed to replace lost red blood
cells/haemoglobin ................................................................................................................
.........................................................................................................................................
(c) (i) Describe the pattern shown in the need for calcium of children of different ages
calcium requirement lower/200 mgs lower in 12 - 16 year olds/higher in 5 - 11 years olds;
.........................................................................................................................................
(ii) Give one explanation for this pattern.
more calcium needed as permanent teeth develop in 5 - 11 year olds/more bone growthin 5 11 year olds
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