Aim
- “To investigate…evaluate…assess…”
- Should mention the independent and dependent variable
- Include the ‘effect’ - use word in aim
Hypothesis
- “If…then”
- Predictive statement
- Relate to independent and dependent variable
- Statement you can answer true/false, yes/no to
- Include words such as bigger/faster, smaller/slower (e.g. if surface area is big, reaction rate is faster)
Method
- Use only one tense
- No personal pronouns
- Numbered steps
- Repeats
- Identify how independent variable will be changed
- Specify how to measure dependent variable
- Control variables
Risk Assessment
- Identify the risk
- State how it can affect you
- How can you minimise the risk?
Tables
- Independent Variable (what is changing) on LHS
- Dependent variable on right column
- Include UNITS in headings
- Column to write average
Graphs
- Title - descriptive about experiment
- Independent variable on x-axis, Dependent variable on y
^ LABEL AXES AND WRITE UNITS - Even scale (start at 0, go up by equal units)
- Use pencil and ruler
- Continuous data - line graph/Categorical - column
- No data point at origin, don’t connect points to there
- Mark points with crosses, more accurate
- Line should establish a trend (line of best fit, equal amount of points on both sides of line)
Reliability
REPEAT and GET SIMILAR RESULTS EACH TIME
- How many times is it REPEATED?
- Are the RESULTS SIMILAR or consistent?
repetition, consistency of results, average multiple trials (precise when repeated)
Example of assessing reliablity
“The experiment was NOT reliable as there was no repetition; only one trial was conducted for each ramp height. No other results from other trials were available which contributed to the unreliablity. Could not compare consistency to and calculate and average to graph the experiment.
Accuracy
- Were my results consistent with what I expected/background?
- Qualitative judgement - compare results to expected
- Precision of measurmeents
- Precision and accuracy - ways to think about error
how close your calculations were to known/published values, any sources of inaccuracy (e.g. errors in measurement, limitation of EQUIPMENT, exact half when cutting)
Error
Instrumental - enviornmental - human - procedural - systematic - random
- Experimental error: difference between measured value and its true value
REDUCE:
- calibrate equipment
- use controls
- repeat measurements
- large sample
- eye level measurements
Validity
- Was experiment fair? Only one IV, one DV, controlled Vs present
- Did method test aim?
- Answer hypothesis from results
- State WHAT variables are
Fair test? How well all other variables were controlled, did experiment answer aim, only one independent variable
Conclusion
- Mention aim/hypothesis -> proven true or not true
- Mention trend specifically (higher, lower) -> per my trend, lowest showed this, highest showed this
- Detail, mention results
- Answer/address hyp true or false
Variables
- Independent: the cause, what is being changed (CHANGE)
- Dependent: what happens as a result of the change, the effect (MEASURE)
- Controlled: element that remains unchanged/unaffected by other variables (SAME)
Assess
Make a judgement and give a valid reason why
Explain
Cause and effect language
Improvements to experiment
SAY WHAT AND HOW IT IS AN IMPROVEMENT
- More trials
- Larger sample (e.g. test from a wider variety of heights, flavours, sizes etc)
- Control variables better
Conclusion example
In the experiment, it was found that a motion car travelling down a ramp that was elevated higher had higher acceleration, a trend evident in the results that were graphed. This trend from the data was consistent with the hypotehsis, which stated that increasing the height the ramp was elevated at would increase the acceleration of a motion car rolling down its slope, therefore, the hypothesis was proven true
Hypothesis example
If teh hieght the ramp is elevated at is increased, then the acceleration of a motion car rolling down its slope will also increase
Aim example
To investigate how the acceleration of a motion car down an inclined ramp and how it is affected by varying the height the ramp is positioned at using a ticker tape
Risk assessment example
The electricity in the power pack is dangerous as contact with this electric current can result in electric burns. Do not use the power pack near taps or sinks, only touch the insulator, avoid contact with uninsualted/exposed surfaces and switch off when not in use.
…can be minimised by…
