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How Science Works- An Overview
Flashcards for the exams based around the AQA book: GCSE Science A, Essentials, Revision Guide.
16
Science
10th Grade
05/04/2013

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Term
Science attempts to explain the world we live in. Scientists carry out investigations and collect evidence in order to...
Definition

  • explain phenomena (i.e how and why things happen)
  • solve problems using evidence.
Term


Scientific evidence provides facts that help to answer a specific question and either support or disprove an idea or theory. Evidence is often based on data that has been collected through observations and measurements. To allow Scientists to reach conclusions, evidence must be...

Definition

 

  • repeatable - other people should be able to repeat the process
  • reproducible - other people should be able to reproduce the same results
  • valid - it must be repeatable, reproducible and answer the question.
Term
To ensure scientific evidence is repeatable, reproducible and valid, scientists look at ideas relating to...
Definition

 

  • data presentation
  •  observations
  • investigations
  • measurements
  • conclusions and evaluations
Term

 

What is the cycle of an observation?

Definition
  1. Observation made
  2. Hypothesis formed (to explain the observation)
  3. Experiment designed
  4. Data collected
  5. Hypothesis tested
  6. Hypothesis supported or disproved or modified
  7. If the hypothesis is to be modified, repeat steps 2-6
Term

 

In order to explain a phenomenon, Scientists make an observation. They then develop a hypothesis from this observation. What is a hypothesis?

Definition
 


A hypothesis is a guess as to why something happens that can be tested and proved correct or incorrect.
Term
A variable is a factor that can take different values. In an investigation, there are two types of variables. They are called...
Definition
  1. Independent variable - can be changed by the person carrying out the investigation. For example, the amount of water a plant receives.
  2. Dependent variable - measured each time a change is made to the independent variable, to see if it also changes. For example, the growth of the plant (measured by recording the number of leaves).
Term

 

 

Continuous variables...

Definition

 

... can take any numerical value (including decimals). They are usually measurements, e.g. temperature.

Term

 

Categoric variables...

Definition

 

... are variables described by a label, usually a word, e.g. different breeds of dog or blood group.

Term

 

Discrete variables...

Definition

 

... only take whole-number values. These are usually quantities, e.g. the number of shrimp in a stream.

Term

 

Ordered variables...

Definition

 

... have relative values, e.g. 'small', 'medium' or 'large'.

Term

 

What two things do investigations have to be?

Definition

 

PRECISE

(to form a valid conclusion)

and

ACCURATE

Term

Explain the following:

  1. Accuracy of instruments
  2. Resolution or sensitivity of instruments
Definition
  1. Accuracy of instruments - a measurement close to true value or how accurately the instrument has been calibrated.
  2. Resolution or sensitivity of instruments - it is determined by the smallest change in value that the instrument can detect. he more sensitive the instrument is, the more precise the value.
Term

 

What are the three errors in measurement?

Definition

  1. Human error - losing concentration or making the same mistake repeatedly (basically people being stupid).
  2. Systematic error - can result from repeatedly carrying out the process incorrectly, making the same mistake each time.
  3. Random error - can result from carrying out a process incorrectly on odd occasions or by fluctuations in reading.
Term
The dependent variable when presenting data on a graph or chart goes on the __________ axis, whereas the independent variable when presenting data goes on the __________ axis.
Definition

 

 The dependent variable when presenting data on a graph or chart goes on the vertical axis, whereas the independent variable when presenting data goes on the horizontal axis.

Term


Conclusions should...

 

Definition
  • describe patterns and relationships between variables
  • take all data into account
  •  make direct reference to the original hypothesis or prediction
  •  try to explain results or observations by making reference to the hypothesis as appropriate.
Term

 

An evaluation looks at the whole investigation. It should consider...

 

Definition
  • the original purpose of the investigation
  • the appropriateness of the methods and techniques used
  • the reliability and validity of the data
  • the validity of the conclusions
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