Transcript Tools of the Trade

Nature of
Science
By
Dr H-W Winter
Book Structure
• Page 1
Title page “Science” with a
picture and your name &
vertical form.
(this is your homework task)
Title Pages
…are the first things a reader sees!
Remember, you do not have a second
chance to make a first impression!
Take pride in your written work
It is part of your learning and will get
marked
Book Structure
• Page 1
• Page 2
Title page “Science” with a
picture and your name & VF
Lab Rules
write down as many rules as you
remember from last year!
PHS Science Faculty Laboratory
Rules
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Never enter a lab unless a teacher is present.
Get your exercise book (1E5), homework book, student planner and
pencil case out of your bag before entering the lab.
Bag are placed on the shelves.
Eating/chewing in the labs is not permitted.
When doing practical work stay in your group in your work area.
Students must not go behind the teacher’s tables/bench.
Safety glasses are to be worn during any experimental work that
involves heating or chemical reactions.
Only touch equipment when you are told to do so. Handle equipment
in the manner in which you have been instructed.
If an accident occurs, no matter how small, report it immediately to the
teacher.
Report any breakages to the teacher.
Clean equipment before returning it to the correct place. Ensure
benches are left dry and clean.
Follow instructions and use your common sense.
Book Structure
• Page 1
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•
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Title page “Science” with a
picture and your name & VF
Page 2
Lab Rules
Page 3
Programme of the Year info
(Signatures)
Page 4 & 5 List of content
Page 6
Title page
“Nature of Science”
Book Work
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Set out your work in paragraphs
Underline your headings and sub-headings
Rule off when you start something new
Do not start anything new on a page that is ¾ full
Write in blue or black pen (red is the marker’s colour), you
may use colours for title pages and borders
Draw diagrams in pencil
Glue in all hand-outs
Leave no free pages unless you want to add something in
the next 2 days or so
Enter the main headings in your list of content with page
numbers
Safety equipment in the lab
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Safety glasses
Fire extinguisher
Fire blanket
Bench boards
Eye wash
Broken glass bucket
Safety equipment
is only there for
the safety of
people or property;
it is not a tool with
which you can do
things. Therefore a
test-tube holder is
not a safety
equipment, it is a
tool.
Laboratory Safety
(Copy into your book and select words from the list on the right to correctly complete these sentences.)
•
Never__________________ any chemicals in the laboratory.
bump
chemicals
eat food
safety glasses
instructions
report
taste
teacher
test tube
water
•
______________ all breakages to your teacher.
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If you spill __________________ on your skin, wash immediately with
plenty of ________________, then tell your teacher.
•
Take care not to_________________ anyone who is using chemicals.
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Do not_______ ___________ in the laboratory.
•
Never point a _________ ___________towards your own face or
anyone else’s.
•
________ _______ must be worn whenever you heat materials or when you work with
chemicals.
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Know what you are doing in the laboratory. Read the______________
Laboratory Safety
Model answers
•
Never taste any chemicals in the laboratory.
•
Report all breakages to your teacher.
•
If you spill chemicals on your skin, wash immediately with plenty of water, then
tell your teacher.
•
Take care not to bump anyone who is using chemicals.
•
Do not eat food in the laboratory.
•
Never point a test tube towards your own face or anyone else’s.
•
Safety glasses must be worn whenever you heat materials or when you work
with chemicals.
•
Know what you are doing in the laboratory. Read the instructions.
The Bunsen burner
•
You are given 5 matches. Use them to work out the hottest parts of the
flame. (Hint: you can use the timing of flaring up match heads and the
charring of white wood to brown wood)
Barrel (will be hot
after use)
Adjustment ring
Air hole
Hose connection
Base
Measuring Volume
• Make sure you are eye-level with the bottom of the
meniscus; always read the bottom of the meniscus!
• Make the calibration face you
mL
4
0
36 mL
2
0
Lab Equipment Quiz
3
2
1
4
Lab Equipment Quiz
100
100

90
90
80
80
70
70
60
60
50
50
40
30
20
40
6
30
10
0
7
20
10
5
Lab Equipment Quiz
9
8
Lab Equipment Quiz
11
10
Lab Equipment Quiz
12
13
Lab Equipment Quiz
14
15
16
Lab Equipment Quiz
17
18
19
20
Lab Equipment Quiz
21
22
Laboratory Equipment
Conical Flask
kotimutu korere
Boiling Tube
Test Tube
ipuipu
Beaker
ipurau
Laboratory Equipment
100
100

90
90
80
80
70
70
60
60
50
50
40
30
20
40
Stirring Rod
30
10
20
0
Thermometer
Measuring
Cylinder
10
Laboratory Equipment
Watch Glass
Evaporating Dish
rihi whakaeto
Laboratory Equipment
filter funnel
korere
Petrie dish
matiti ipuipu
test tube rack
Laboratory Equipment
Metal Gauze
whariki tarai
Tripod
toruwae
Laboratory Equipment
Pipette
Tongs
Laboratory Equipment
Clamp
Boss
Lab Stand
a. k. a.
Retort Stand
Apparatus
rubber stopper
boiling tube
beaker
ipurau
delivery tube
Drawing Scientific Diagrams
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Draw 2-dimensionally as a cross-section
¼ to ⅓ page in size
Use a sharp pencil
Rule all straight lines
Correct proportions
(the size of things relative to each other)
• Horizontal labels
Drawing Equipment
Tāngia taputapu
tatari
filter paper
korere
filter funnel
ipuipu
test tube
3D
2D
Mass and Volume Challenges
• Determine the mass of 7.8 mL of water.
• Determine the mass of 7.8 mL of salt water.
• What is the mass of a new pen relative to a
almost empty pen? What do you have to do to
make this a fair test?
• Determine the volume of one drop of water
using a 10 mL measuring cylinder.
• Determine the volume of your pencil sharpener.
°c
42
Reading Scales
Tricks:
100
•
Work out what the units are that are used
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Work out in what direction the scale gets bigger (increasing
numbers)
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Work out how much one of the little lines is worth
- by counting how many spaces there are between two numbers on
the scale (10)
- then find the difference between the two numbers on the scale
(98°C – 97°C = 1°C)
- then divide the difference by the by the number of spaces (1°C ÷ 10
= 0.1°C)
98
•
Check that you are right by counting from one to the next numbered
line using your calculated value
97
•
Now count in the number steps of little lines in the direction the scale
gets bigger starting from the last numbered line on the scale up to
the reading:
98.1°C, 98.2°C; write down your reading including units!
96
•
99
If the reading is in between two lines, guess the next decimal place
as accurately as possible
36
Reading Scales
mL
9
mL
50
40
mL
20
30
20
10
10
8
7
6
10
5
4
3
2
1
Reading Scales
0
4
60
50
40
30
20
10
0
N
8
12
11
10
9
8
7
6
12
5
4
3
2
1
0
N
Reading Scales
35
30
40
45
50
55
60
65
25
20
70
2
15
75
1
10
80
0
85
5
0
90
20
15
10
5
0
25 30 35
rpm
x 100
40
45
50
55
60
3
4
5
6
mV
7
8
9
10
11
12
Reading Scales
°C
42
°C
42
°C 42
83
41
82
40
81
39
80
38
79
37
70
69
68
67
66
Reading Scales
0
10
20
30
40
50
60
70
50
40
30
20
10
0
80
90
100
60
110
120
mm
mm
Reading Scales
XI
XII
I
X
11
12
1
IX
9
III
VIII
2
10
II
IV
VII
VI
V
3
XII
8
4
7
6
5
IX
III
VI
The Metric System, SI - Units
• In order to compare measured values with
each other we have to give the
measurements units.
• Most of the world is measuring in the socalled metric system (based on the
number 10).
• There are basic units.
The Metric System, SI - Units
What you use to
measure
ruler
measuring cylinder
balance
watch
thermometer
Quantity
measured
length
volume
mass
time
temperature
Name of basic
unit
metre
Litre
kilogram)
second
degree Celsius
Symbol
m
L
kg
s
o
C
Note: The unit “kilogram” is the odd one out, where the basic unit is
having a “kilo” in its name already. A “kilokilogram” is called a tonne.
Too small or too big
• Sometimes the units are too small or too
big to measure in easy numbers.
• You cold say “a flea is 0.002 m long”, or
“the volume of a raindrop is 0.0001L”, but
you would find it hard to imagine this.
• Therefore units derived from the basic
units are in use.
Too small or too big
Prefix
Symbol
kilo ~
centi ~
k
c
milli ~
m
Multiple of
basic unit
1,000
Example
1
kilometre km
centimetre cm
100
1
millisecond ms
1, 000
micro ~

1
1, 000 , 000
micrometre m
Convert the following:
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2340 g
0.033 m
38.0 cm
0.039 L
56777 mL
12121m
700 mL
999 m
= 2.340
= 33
= 0.38
= 39
= 56.777
= 12.121
= 0.7
= 0.999
kg
mm
m
mL
L
km
L
mm
Organising data and
drawing a graph
• A candle was weighed on an electronic balance. Its mass
was 30.17 g.
• The candle was left on the balance and it was lit.
• The mass was recorded straight after it was lit and found
to be 30.17 g. This happened at 1.40 pm.
• The student carried on reading the mass and the time and
recorded the readings as follows (getting increasingly
sloppy in his work):
• 1.42 pm 30.11g; 1.44 pm 30.06g; 1.46 pm = 29.5 g; 2 min
later = 29.88 g; now every 2 minutes: 29.74 g; 29.63;
29.51; 29.32; didn’t read for 15 minutes, then it was 28.56
g; 2.13 pm = 28.45 g; 2 minutes later 29.37 g; 10 min later
27.99 g
Organising data
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Organise the data in a table that has
clear headings and units
Have an additional column in the table
that allows you to process the data such
that you can draw a graph
Remember to put a heading on top of
each column and the unit that goes with
it!
Table of results for the mass of
a candle burning on a balance
Time of the day (hrs pm)
Mass of candle (g)
Time from lighting (min)
Organising data
• A candle was weighed on an electronic balance. Its mass
was 30.17 g.
• The candle was left on the balance and it was lit.
• The mass was recorded straight after it was lit and found
to be 30.17 g. This happened at 1.40 pm.
• The student carried on reading the mass and the time and
recorded the readings as follows (getting increasingly
sloppy in his work):
• 1:42 pm 30.11g; 1:44 pm 30.06g; 1:46 pm = 29.5 g; 2 min
later = 29.88 g; now every 2 minutes: 29.74 g; 29.63;
29.51; 29.32; didn’t read for 15 minutes, then it was 28.56
g; 2:13 pm = 28.45 g; 2 minutes later 29.37 g; 10 min later
27.99 g
Table of results for the mass of
a candle burning on a balance
Time of the day (hrs pm)
Mass of candle (g)
1.42
1.44
1.46
1.48
1.50
1.52
1.54
1.56
1.58
30.11
30.06
29.5
etc
Time from lighting (min)
0
2
4
etc
Table of results for the mass of a candle burning on a balance
Time of the day
(hrs pm)
Mass of
candle (g)
Time from lighting
(minutes)
1.40 pm
30.17
0
1.42 pm
30.11
2
1.44 pm
30.06
4
1.46 pm
29.5
6
1.48 pm
29.88
8
1.50 pm
29.74
10
1.52 pm
29.63
12
1.54 pm
29.51
14
1.56 pm
29.32
16
2.11 pm
28.56
31
2.13 pm
28.45
33
2.15 pm
28.37
35
2.25 pm
27.99
45
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Draw the mass versus time graph for the
candle burning on the balance
Remember:
Title for graph: “y versus x for…..”
Labels on axes
Units on axes
Whole numbers on axes
Even steps on the axes
Crosses for the plots
“Line of best fit”
Mass of candle versus time graph for a burning candle
Mass of candle
(g)
31
x x
x
30
x
x
x x
x
x
29
x x
x
x
28
0
10
20
30
40
45
Time (min)
Use your graph and other data to find answers to
the following questions:
A. What would have been the mass of the candle 20
minutes after it was lit?
B. Which of the readings must have been a mistake?
Give a reason!
C. What was the time when the candle’s mass was
28.56 g?
D. What was the time when the last reading was taken in
the experiment?
E. How many minutes after lighting the candle was this?
F. Did the flame have a mass?
What would have been the mass of the candle 20
minutes after it was lit?
Mass of candle
(g)
31
30
x x
x
x
x
x x
x
x
29.08 g
29
x x
x
x
28
0
10
20
30
40
45
Time (min)
Which of the readings must have been a mistake?
Give a reason!
Mass of candle versus time graph for a burning candle
Mass of candle
(g)
31
x x
x
30
x
x
x x
x
x
29
x x
x
x
28
0
10
20
30
40
45
Time (min)
What was the time when the candle’s mass was
28.56 g? - How many minutes after lighting the candle was this?
Mass of candle versus time graph for a burning candle
Mass of candle
(g)
31
x x
x
30
x
x
x x
x
x
Start time + 31 min = 2:11 pm
29
x x
x
x
28
0
10
20
30
40
45
Time (min)
Did the flame have a mass?
• A candle was weighed on an electronic
balance. Its mass was 30.17 g.
• The candle was left on the balance and it
was lit.
• The mass was recorded straight after it
was lit and found to be 30.17 g. This
happened at 1.40 pm.
Investigating Bunsen Burner Settings
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Aim: To record the temperature of water as it is heated
with different Bunsen burner settings.
Hypothesis: I think that the blue flame will…..
Equipment:
Bunsen burner, tripod/gauze, thermometer,
100 mL measuring cylinder, beaker, stop watch.
Method & Diagram:
Set up as per diagram.
Measure 100 mL of water using the measuring cylinder,
pour into beaker.
Measure its temperature and record.
Set the Bunsen burner to a yellow flame (air hole
closed)
Start the timing when you push the Bunsen burner
under the tripod until boiling and then for a further 3
minutes.
Record the temperature every minute in table format.
Repeat this experiment with a blue flame Bunsen
burner (air hole open). Tip: rinse the beaker with cold
water to cool it down; pull out the burner in-between
experiments.
00:00:00
min sec
1/100s
mL
100
90
80
70
60
50
40
30
20
10
• Results:
Temperature / °C
Time / min Yellow flame
0
1
2
3
4
5
and so on
• Graph of results: (=homework)
Blue Flame
Temperature
°C
Temperature vs time graph for heating water with first a
yellow and then blue Bunsen flame.
T2
blue flame
yellow flame
T1
Conclusion:
The blue flame heated the water faster than the yellow flame.
The yellow flame made the beaker black with soot.
Time
min
How high can a Ping-Pong ball bounce
when released from different heights?
• Think of an aim and a hypothesis
• Design the experiment (how do you
increase the confidence in your results?)
• Draw a diagram
• Write a method
• Design the table for recording your results
• What goes on the graph?
How high can a Ping-Pong ball
bounce?
cm
•
•
•
1.
2.
3.
4.
5.
Aim:
To see how high a PingPong ball will bounce
Hypothesis:
I think that the ball
will bounce less high than the start
height
Method:
Set up as per diagram.
One in the group holds the ruler vertically
and releases the ping-pong ball.
One reads the height of the bounce on the
ruler.
The third group member records the
readings.
Repeat twice and take the averages.
100
90
80
70
60
50
40
30
20
10
0
Start
Height
Bounce
Height
Table of results
Start Height
(cm)
20
40
60
80
100
Bounce
Height (cm)
1st time
Bounce
Height (cm)
2nd time
Bounce
Height (cm)
3rd time
Bounce
Height (cm)
average
Bounce height
in cm
Graph of bounce height vs release height for a ping-pong ball
100 -
50 -
00
100
Conclusion: I was right, the bounce height was always lower
than the start height.
Start height in cm