Alternative to Practical

Question 1

Three points that make a graph directly proportional?

Answer 1

Through origin
Increase at same rate
Positive gradient

Question 2

Control variables when testing a cooling bulb?

Answer 2

Same starting temperature

Same surrounding temperature

Question 3

Setting up an optics experiment

Answer 3

Bulb, lens, dark screen 2cm from lens, metre rule between them all

Question 4

Controls in optics experiments

Answer 4

Dark room

Move lens backwards and forwards to get optimum sharpness

Question 5

Obtaining accurate readings

Answer 5

Check for zero errors

Repetitions

Question 6

Proper way to say close enough

Answer 6

Within limits of experimental accuracy

Question 7

Reasons for errors in measuring angle of incidence/reflection

Answer 7

Thickness of lines
View base of pins
Protractor only accurate to +/- 1 degree

Question 8

How to be accurate with plumb line

Answer 8

Viewing line directly in front of card

Question 9

How you can see that a lamps filament is heating up

Answer 9

Brightness changes

Question 10

Accurate thermometer work

Answer 10

Wait for temperature to stabilise

View thermometer at right angles

Question 11

Thing for measuring distances

Answer 11

Trundle wheel

Question 12

Minimum distance for sound experiment

Answer 12

200m

Question 13

Why only do speed of sound to 2 sig fig?

Answer 13

Time measurements too inaccurate

Question 14

3 things to do with reflection experiments

Answer 14

Avoid parallax errors when taking readings with protractor
Thin lines
Pins as far apart as possible

Question 15

How to avoid parallax error when using metre rule?

Answer 15

View scale perpendicularly

Question 16

Practical difficulty and solution in balancing a metre rule

Answer 16

Ruler never quite balances

Place the ruler where it nearly balances

Question 17

Centre of mass is not in middle of rule, so does not balance. But the ruler does balance at another point . What does the student do?

Answer 17

Take measurements from point where metre rule balances

Question 18

Explain briefly how you would reduce the uncertainty in the position of Q required for exact balance

Answer 18

estimate between two best positions that almost balance but tip opposite sides

Question 19

Controls in lens experiment where you do not have to make sure image is one hundred percent focused

Answer 19

use of darkened room / brighter lamp / no other light interfering
mark position of centre of lens on holder
place metre rule on bench (or clamp in position)
ensure object and lens are same height from the bench
lens / object / screen perpendicular to bench
repeats
avoidance of parallax with action and reason

Question 20

Range of values for which an image will be focused

Answer 20

+/- 0.5cm

Question 21

3 things to keep the same when doing the heating rod experiment

Answer 21

• length of rod
• diameter/thickness/area (of cross-section) of rod
• amount of wax / type of wax
• weight / size/mass of marker
• position for the markers
• (Bunsen) flame / (rate of) heating
• position of Bunsen / flame
• position of rod on tripod

Question 22

Why not to use liquid in glass thermometer

Answer 22

Temperatures too high

Bulb can’t make proper contact

Question 23

When resistance of variable resistor decreases the lamp gets….

Answer 23

Brighter

Question 24

Why record 20 swings not 1?

Answer 24

Reduces the effect of error due to stopping/starting stopwatch