They should also discuss what they would do differently next time and why. Level 4 - Investigation has testable question, prediction, complete procedure, experiment is repeated at least three times, variables are listed and controlled where possible. Only one variable is manipulated. Measurement was used in data collection. Results are appropriate.
Conclusions are appropriate.
Level 3 - Investigation has testable question and prediction. Procedure may be incomplete. Experiment is repeated at least three times. Not all variables may be listed and controlled, but important ones are. Only one variable is manipulated.