How Science Works Flashcards
What does accuracy mean? What can you do to increase the accuracy of an experiment?
Results are close to the true value – accuracy can be increased by controlling variables
What is calibration?
Marking a scale on a measuring instrument
What is the independent variable?
The independent variable is the variable that is changed
What is the dependent variable?
The dependent variable is the variable that is measured
Why do we normally use at least 5 different conditions in an experiment?
We do 5 tests to obtain a pattern – this will also highlight anomalous results
What is a hypothesis?
A proposal to explain certain facts or observations
What is validity? How can you increase the validity of an experiment?
A valid experiment tests what it is supposed to – validity is increased by ensuring all variables are controlled, and removing errors (e.g. experimental bias)
What is an interval?
The quantity between readings e.g. 10cm, 20cm, 30cm, 40cm, 50cm have and interval of 10cm
What is random error? How can you reduce the impact of random errors?
1 or 2 odd results that may be caused by equipment or experimental error – reduce the impact of random error by repeating results and removing anomalies from the average
What is a systematic error?
What should you do if you suspect systematic error?
Data which differs from the true value by a consistent amount each time – it is usually caused by the way measuring instruments have been read
Repeat using a different technique or instrument
Explain the following types of data: -
Categoric
Continuous
Categoric: values which are groups or lables (e.g. boys and girls)
Continuous: values which have numbers e.g. time, weight, number of people, distance etc…
What is zero error?
When a measuring instrument gives a false reading when it should be zero
What is a precise result?
A result which is very similar to the mean value
What is the range?
The maximum and the minimum values e.g. from 10cm to 50cm
What is repeatability?
When the experimenter repeats the experiment using the same method and gets the same result
What is reproducibility?
When the experiment is repeated by another person or by a different method and you get the same results
What is resolution?
The smallest change in the quantity being measured e.g. mm on a normal ruler
How do you draw a sketch graph?
Label the axes on a sketch like below and draw what you think the line of best fit is like
What is uncertainty?
The interval within which the true value can be expected to fall, with a given level of confidence or probability, e.g. “the temperature is 20°C ± 2°C, at a level of confidence of 95%
What is a control variable?
A variable which could affect the results if it isn’t monitored or kept the same
What does interpreting mean?
To read and summarise the information shown on a graph, table or chart
What is a prediction?
A statement suggesting what will happen in the future, based on observations / experience / a hypothesis
What are environmental considerations?
The impact on wildlife and the natural habitat e.g. pollutions
What is an opinion?
Personal judgments or views which can be formed form scientific evidence or non-scientific ideas
What is bias?
The influence placed on scientific evidence because of wanting to prove your own ideas, supporting the person paying you, political influences, or the status of the experimenter
What does ethical mean?
Whether it is right or wrong. E.g. drug testing on animals
What are social considerations?
What people think e.g. different religions
What are economic considerations?
Costs involved
What is a control group?
A group often used in biological and medical research to ensure that observed effects are due to changes in the independent variable alone e.g. a group of people who take a placebo are compared
How do you calculate an average?
The sum of all the measurements divided by the number of measurements taken
When would you use a bar chart?
Bar charts can be used to display data in which one of the variables is categoric
When would you use a line graph?
Line graphs can be used to display data in which both the independent and dependent variables are continuous
When would you use a scattergram?
Scattergrams can be used to show an association between two variables
What is a casual link?
When one variable causes a change in another
What is a link due to association?
Changes in one variable and a second variable are linked by a third variable e.g. different greenhouse gases and global warming
What is data?
Information that has been collected (numbers / written observations)
What are anomalies?
Values in a set of results which differ from the expected and variation caused by random uncertainty
What is measurement error?
The difference between a measured value and the true value
What is a valid conclusion?
A conclusion supported by valid data, obtained by an appropriate experimental design
What is evidence?
Data which has been shown to be valid
What is a fair test?
A fair test is one in which only the independent variable has been allowed to affect the dependent variable
What is a true value?
The value that would be obtained in an ideal measurement
What does reliable mean?
A reliable measurement is one that consistently remains the same after several repeats
