Chapter 1: Scientific Endeavour Flashcards
What is the difference between observation and inferences?
Observation: Statement describing the way something happens, using our 5 senses
Inference: Predictions based on your interpretation, using one’s prior knowledge and experiences o come up with an explanation, an inference may or may not be true and thus needs to be tested
What is an independent variable?
An independent variable are those factors in an experiment that the scientist deliberately changes so as to observe the consequences of these changes.
What is a dependent variable?
Dependent variables are factors that undergo changes due to changes in the independent variable.
What is a control variable?
Control variables are all those factors that the scientist attempts to keep constant to ensure a fair experiment.
To test a hypothesis, we perform an experiment to try to prove that it is (a) instead of trying to prove that it is (b).
Choose one of the options
(A) true or false
(B)true or false
(A) false
(B) true
As it is easy to find evidence to confirm something is true but difficult to prove something is false
What is an experimental group and its purpose?
An experimental group is the group which is exposed to the independent variable under study and dependent variable is collected from this group of subjects
What is a control group and a negative control group as well as its purpose?
A group that is not influenced by the independent variable being tested
Negative control group—> The group which is exposed to a factor that is known to give negative results
— Serve as a standard for COMPARISON against the EXPERIMENTAL group so that one can conclude that the treatment resulted in the CHANGE in the DEPENDENT variable (to test VALIDITY of the experiment)
—-If the negative control produces an effect, then there could be an unknown factor that is affecting the results.
Why should one person repeat the experiment and how many times should the person repeat the experiment?
A person should repeat an experiment at least three times in order to check for reliability of the experiment as experimental results need to be reproducible. Therefore the recommended sample size is three or more.
What is the difference between validity and reliability?
Validity— relates to the experimental method and how appropriate it is in addressing the aim of the experiment.
Reliability— relates to the consistency of the experimental results, that is, how close repeated measurements are to each other.
What should the format of the title of a graph be written in?
A title is written at the top as the graph of variable Y against variable X.
What are the three types of flame?
Luminous flame, non-luminous flame, “strike back”
What is the difference between a test tube and a boiling tube?
A test tube is for containing or heating a small volume of liquid (generally less than 20cm cube)
A boiling tube is for containing or heating a greater volume of liquid. (Generally less than 50 cm cube)
How do you measure the volume in a measuring cylinder?
measure the volume of a liquid to half the smallest division in cm cube
What is beaker for and not for?
Beaker is for containing or heating a large volume of liquid and it is NOT for MEASURING VOLUME
What is conical flask for?
Conical flask is for containing chemicals and collecting liquids The narrow necks allow the contents to be mixed easily by swirling and allows it to support filter funnels.
