- Messages
- 109
- Reaction score
- 8
- Points
- 28
Investigate the height to which a ball rises when it has been released from a stretched.
Limitation
A Ruler not vertical.
B Locating the centre of the ball (when reading ruler).
C Parallax error.
D Establishing when the ball is at its maximum displacement.
E Only two displacements (are not enough to validate the conclusion).
F Difficulty in the release of the mass (reference to force/vertical plane).
Improvements
A Sensible method to ensure ruler vertical.
B Place the rule as close as possible to the mass/mark the centre of the ball with mark or pointer/use the bottom/top of the ball.
C Measure at eye level/repeat to get eye in the right place/place the rule as close as possible to the mass.
D Use video camera (play back) frame by frame/slow motion/position sensor above or below.
E Need a wider range of displacements and plot a graph/find mean k.
F Use a clamp/electromagnet to release the mass.
Do not allow ‘repeated readings’, ‘human error’.
Do not allow ‘use a computer to improve the experiment’.
Investigate how the light detected by a light-dependent resistor (LDR)
depends on the thickness of an absorber.
Limitations
A Two readings not enough (to draw a conclusion).
B Alignment of cylinders/alignment of LED/LDR.
C Stray light coming in/not light tight/cylinders not sealed so let light enter tube/external light hits LDR.
D Difficult to hold all together/voltage meter fluctuates.
E Separation between LED and LDR changes (as paper added).
Improvements
A Take many readings AND plot a graph/find many values of k.
Guide used; ruler/line on desk.
B Adjust LED/LDR to get max voltage/method of fixing LED/LDR in cylinder.
C Dark room/black cloth over head/lights off and blinds down/black box/black tape.
D Method of fixing; clamp/plasticine/tape.
E Pre-slots in tube.
Investigate the angle of tilt of a bottle when it contains different
amounts of water.
Limitations
A Two readings are not enough (to draw a valid conclusion).
B Parallax error in measuring h/θ .
C Difficult to measure height owing to refraction/shape of bottle/thickness of
bottom not taken into account/ruler does not start at zero/cannot see meniscus clearly.
D Difficulty in deciding the toppling point.
E Difficulty in measuring θ owing to container not perfectly right angled (curved) at the bottom/difficult to line up protractor/horizontal line of protractor not on table/ difficult to manipulate bottle and measure angle/flexible container/shape of bottle.
Improvements
A Take many (sets of) readings and plot a graph of the results. Be clear NOT just
repeat readings.
B Get eye level/‘eye level’ perpendicular (to protractor lines, ruler scale or meniscus).
Put scale onto bottle.
C Add dye/use ruler with a zero at the start.
D Move by increments/hold with newtonmeter and tilt until F = 0/bottle on tilting ramp idea.
E Make bottom square with plasticine/use protractor with horizontal line flush to table
top/freestanding or clamped protractor.
:good: :good: :good: :good: :good: :good: :good: :good: :good: :good: :good: :good: :good: :good: :good:
Limitation
A Ruler not vertical.
B Locating the centre of the ball (when reading ruler).
C Parallax error.
D Establishing when the ball is at its maximum displacement.
E Only two displacements (are not enough to validate the conclusion).
F Difficulty in the release of the mass (reference to force/vertical plane).
Improvements
A Sensible method to ensure ruler vertical.
B Place the rule as close as possible to the mass/mark the centre of the ball with mark or pointer/use the bottom/top of the ball.
C Measure at eye level/repeat to get eye in the right place/place the rule as close as possible to the mass.
D Use video camera (play back) frame by frame/slow motion/position sensor above or below.
E Need a wider range of displacements and plot a graph/find mean k.
F Use a clamp/electromagnet to release the mass.
Do not allow ‘repeated readings’, ‘human error’.
Do not allow ‘use a computer to improve the experiment’.
Investigate how the light detected by a light-dependent resistor (LDR)
depends on the thickness of an absorber.
Limitations
A Two readings not enough (to draw a conclusion).
B Alignment of cylinders/alignment of LED/LDR.
C Stray light coming in/not light tight/cylinders not sealed so let light enter tube/external light hits LDR.
D Difficult to hold all together/voltage meter fluctuates.
E Separation between LED and LDR changes (as paper added).
Improvements
A Take many readings AND plot a graph/find many values of k.
Guide used; ruler/line on desk.
B Adjust LED/LDR to get max voltage/method of fixing LED/LDR in cylinder.
C Dark room/black cloth over head/lights off and blinds down/black box/black tape.
D Method of fixing; clamp/plasticine/tape.
E Pre-slots in tube.
Investigate the angle of tilt of a bottle when it contains different
amounts of water.
Limitations
A Two readings are not enough (to draw a valid conclusion).
B Parallax error in measuring h/θ .
C Difficult to measure height owing to refraction/shape of bottle/thickness of
bottom not taken into account/ruler does not start at zero/cannot see meniscus clearly.
D Difficulty in deciding the toppling point.
E Difficulty in measuring θ owing to container not perfectly right angled (curved) at the bottom/difficult to line up protractor/horizontal line of protractor not on table/ difficult to manipulate bottle and measure angle/flexible container/shape of bottle.
Improvements
A Take many (sets of) readings and plot a graph of the results. Be clear NOT just
repeat readings.
B Get eye level/‘eye level’ perpendicular (to protractor lines, ruler scale or meniscus).
Put scale onto bottle.
C Add dye/use ruler with a zero at the start.
D Move by increments/hold with newtonmeter and tilt until F = 0/bottle on tilting ramp idea.
E Make bottom square with plasticine/use protractor with horizontal line flush to table
top/freestanding or clamped protractor.
:good: :good: :good: :good: :good: :good: :good: :good: :good: :good: :good: :good: :good: :good: :good:
