Unit 1: The Scientific Endeavour

Question 1

Qualitative Data

Answer 1

Involves the 5 senses
(sight, touch, smell, taste, hearing)

Usually descriptive or what you can observe with your 5 senses
(e.g. heavy, long, fast)

Question 2

Quantitative Data

Answer 2

Involves senses and measurements taken using instruments

Has units, measurements or a numerical value
e.g. 2 ants, 500g, 50s

Question 3

Observation

Answer 3

• the act of attentive monitoring or perceiving, mediated through our five senses
• the measurement, collection or recording of data, mediated through instruments, especially during an experiment

Question 4

Inferences

Answer 4

• a logical conclusion that can possibly be derived based on the observations made.

Question 5

Dependent

Variable

Answer 5

Variable Measured (VM)

A dependent variable is what you measure in an experiment and what is affected
during the experiment. The dependent variable is affected during the experiment.
The dependent variable responds to the independent variable.

Question 6

Independent Variable

Answer 6

Variable Changed (VC)

An independent variable is the variable you have control over, what you can choose
and manipulate. It is usually what you think will affect the dependent variable.

Question 7

Constants/ Fixed Variables

Answer 7

The factors within an experiment that are kept the same for all groups or trials in an attempt to reduce the influence of irrelevant variables.

Question 8

Control Group

Answer 8

Controlled Variables (?)

The group in an experiment that receives the exact treatment as the experimental groups except it does not receive any change of the independent variable. It is the
group to which the experimental groups are compared.

Question 9

Hypothesis

Answer 9

A tentative (i.e. not final and definite) and testable proposed explanation for an
observed phenomenon. It is based on observation and prior knowledge of the
system.
• It refers to only one dependent variable and one independent variable.
• It is written as a definite statement, and not a question.
• It is testable by experimentation.

Question 10

Observations

Answer 10

The act of attentive monitoring or perceiving, mediated through our five senses and the measurement, collection or recording of data, mediated through instruments, especially during an experiment.

Question 11

Inferences

Answer 11

A conclusion, based on facts, which a person perceives to be true.

Question 12

Repeats

Answer 12

The replication of experimental and control groups is used to decrease the influence
of variations associated with the independent variable and researcher measurement error.

Question 13

Accuracy

Answer 13

Readings are closest to real value but may not be close to one another.

Question 14

Precision

Answer 14

Readings are closer to one another even if it is far from real value.

Question 15

Parallax Error

Answer 15

Parallax Error
• Occurs when you did not read the marking of an instrument at eye level or did not read perpendicularly above the marking
• error in reading an instrument as a result of not viewing the measurement scale from the correct position.
• Unpredictable (human error)
• Can be corrected by reading the marking of an instrument at eye level or reading perpendicularly above the marking
• Factors that contribute to unpredictable errors include unpredictable environmental conditions and human reaction time in operating a stopwatch.

Question 16

Zero Error

Answer 16

• Occurs when a measuring instrument gives a reading not zero (when nothing is placed on it) when the true reading at that time is zero.
• Consistent error = consistently inaccurate
• Can be corrected by pressing the ‘tare’ button before placing something on the electronic balance or subtract (the amt that error causing) from final reading of mass
• Occurs in measuring instruments e.g. weighing scale

Question 17

Luminous Flame

Answer 17

• flame is not as hot as non-luminous flame
• yellowish-orange, blue
• sooty
• flickering and unsteady
• more visible
• obtain when air-hole is closed
• flame burns less efficiently (incomplete combustion)

Question 18

Non-Luminous Flame

Answer 18

• flame is very hot
• pale blue, blue
• not sooty
• steady
• less visible
• obtained when air-hole is open
• flame burns more efficiently (complete combustion)

Question 19

Why is a luminous flame yellow/orange?

Answer 19

It is due to the presence of carbon.

Question 20

Why is heating with a Bunsen burner usually carried out with an open instead of a closed air-hole?

Answer 20

Opening the air-hole will produce a non-luminous flame which is hotter and burns more efficiently than a luminous flame.

Question 21

What is obtained when the air-hole is closed?

Answer 21

Luminous Flame

Question 22

What is the colour of a luminous flame?

Answer 22

yellowish-orange, blue

Question 23

Which flame is sooty? (smoke like thing??)

How is soot produced?

Answer 23

Luminous Flame

Soot is produced when there is incomplete combustion / insufficient oxygen

Question 24

Which flame is flickering and unsteady?

Answer 24

Luminous Flame

Question 25

Which flame burns less efficiently? Why?

Answer 25

Luminous Flame | There is incomplete combustion/ insufficient oxygen

Question 26

Which flame is very hot?

Answer 26

Non-Luminous Flame

Question 27

Which flame is pale blue/ blue in colour?

Answer 27

Non-Luminous Flame

Question 28

Which flame is not sooty?

Answer 28

Non-Luminous Flame

Question 29

Which flame is steady?

Answer 29

Non-Luminous Flame

Question 30

Which flame is less visible?

Answer 30

Non-Luminous Flame

Question 31

Which flame burns more efficiently? | Why?

Answer 31

Non-Luminous Flame. | There is complete combustion/ sufficient oxygen.

Question 32

What is the inner blue zone of the non-luminous flame made up of?

Answer 32

Air and unburnt gas

Question 33

How does a strike-back flame occur?

Answer 33

A “strike back” flame may occur when the air-holes are fully open before you light up the Bunsen burner. There is too much air at the jet which results in the gas burning at the jet inside the barrel. If your Bunsen burner has an accidental “strike back”, turn off the gas tap immediately and let the bunsen burner cool down before lighting it again.

Question 34

Which flame do you leave the bunsen burner in when it is temporarily not in use?

Answer 34

Luminous flame. | This is to make the flame visible so as to avoid accidentally burning one's self.

Question 35

What is the function of the barrel in a Bunsen burner?

Answer 35

to raise the flame to a suitable height for burning

Question 36

What is the function of the collar in a Bunsen Burner?

Answer 36

to control the amount of air entering the burner by opening or closing the air-holes to open or close the air hole

Question 37

What is the function of the gas tap of a bunsen burner?

Answer 37

to control the flow of gas to the bunsen burner

Question 38

what is the function of the air hole in a bunsen burner?

Answer 38

to allow air to enter the burner to allow air (oxygen) to mix with gas fuel

Question 39

What is the function of the gas jet in a bunsen burner?

Answer 39

to enable the gas to rush out from the gas supply and to draw in air

Question 40

What is the function of the base in a bunsen burner?

Answer 40

to support the burner so that it will not topple

Question 41

How do you light a bunsen burner?

Answer 41

1. close the air-hole 2. hold a lighted match near the mouth of the barrel 3. turn on the gas tap slowly (luminous flame) 4. open the air-hole for heating (change to non luminous flame)

Question 42

Attitudes for science?

Answer 42

``` Curiosity Perseverance Positive approach to failure Open-mindedness Co-operation with others Tolerance Impartiality Healthy scepticism Integrity Refusal to believe in superstitions ```

Question 43

What is the scientific method (steps)?

Answer 43

1. Observe 2. Record observations or measurements 3. Suggest a hypothesis 4. Test the hypothesis 5. Infer from data 6. Evaluate

Question 44

What are the safety rules when heating or mixing chemicals?

Answer 44

Wear goggles when heating or mixing chemicals. Place flammable substances away from the naked flame. Point the mouth of a test tube which is being heated away from yourself or your friends.

Question 45

What do you do when accidents occur?

Answer 45

Report all accidents, injuries, breakage and spillage to your teacher immediately. If any chemical gets into your eyes or mouth, rinse your eyes or mouth with plenty of water and report the incident to your teacher.

Question 46

What are the steps involved in the scientific method to plan an experiment?

Answer 46

``` Make observations ↓ record observations or measurements ↓ suggest a hypothesis ↓ test the hypothesis ↓ infer from data ↓ ↓ valid hypothesis invalid hypothesis ↓ ↓ theory go back to recording observations or measurements ```