Required Practicals

Question 1

describe a method to investigate the relationship between force & extension of a spring

Answer 1

1. measure the original length of the spring with a metre rule clamped vertical
2. attach a pointer to the bottom of the spring, ensuring it is perpendicular to the ruler
3. add a 10g mass to the spring & record the length of the stretched spring
4. subtract the original length from the stretched length to calculate the extension
5. repeat by increasing the total mass on the spring in 10g intervals
6. calculate the weight of each mass
7. repeat taking masses off the spring
8. plot graph force on y-axis vs extension on x-axis
9. draw a line of best fit & calculate gradient, which = spring constant

Question 2

describe a method to investigate how mass affects acceleration

Answer 2

1. set up a trolley attached to a string at one end & masses hanging over the table from the other end from a pulley
2. put the trolley on a start line, put a piece of card on top & put a light gate 20cm in front of it
3. measure the mass of the trolley with a balance
4. release the trolley & light gate will measure acceleration
5. repeat twice & calculate mean
6. repeat after adding masses to the trolley in 10g intervals, which increases mass of the system
7. plot graph

Question 3

describe a method to investigate how force affects acceleration

Answer 3

1. set up a trolley attached to a string at one end & masses hanging over the table from the other end that have been measured with a balance
2. put the trolley on a start line, put a piece of cards on top & put a light gate 20cm in front of it
3. measure the mass of the trolley with a balance
4. release the trolley & light gate will measure acceleration
5. repeat twice & calculate a mean
6. repeat after transferring masses to the hanger that hangs over the table from the trolley in 10g intervals, which increases the weight/accelerating force
7. plot graph

Question 4

describe a method to investigate the frequency, wavelength & speed of waves in a ripple tank

Answer 4

1. fill a ripple tank with 5mm deep water & put ripple tank on top of white paper
2. put a wooden rod on the surface of the water attached to power supply & signal generator, which causes oscillations of the rod
3. place a lamp above the ripple tank with a strobe disc (or you could take a picture of the display) & dim lights
4. shadows = wave fronts
5. to find wavelength measure perpendicular distance across 10 wavefronts & divide by 10
6. to measure frequency, count 10 or 20 waves passing a particular point in a given time then divide by that number
7. to calculate wave speed, multiply wavelength by frequency

Question 5

describe a method to investigate waves in a solid

Answer 5

1. set up a string attached to a vibration transducer (connected to a signal generator), over a pulley & masses on the other end
2. turn on the signal generator, which will cause the string to vibrate
3. adjust the frequency of signal generator so a whole 5 waves fits onto the length of the string
4. calculate wavelength of waves by measuring all the half-wavelengths on the string, dividing by the number of waves & multiplying by 2 to get full wavelength
5. calculate wave speed by multiplying frequency of the signal generator by wavelength

Question 6

describe a method to measure the speed of sound waves in air

Question 7

describe a method to investigate the reflection of light

Answer 7

1. place an object on a piece of paper & draw a line where one of its sides is positioned
2. draw a normal to the object
3. shine a single ray of light from a ray box at meeting point of the normal & the surface
4. mark with crosses the centre of the incident & reflected ray
5. connect the crosses with a straight line & measure the angle of incidence & angle of reflection with a protractor
6. the angle of incidence = angle of reflection
7. repeat using different objects & same angle of incidence

Question 8

describe a method to investigate the refraction of light

Answer 8

1. place a glass block on a piece of paper & trace its outline with pencil
2. draw a normal to the object
3. shine a single ray of light from a ray box at meeting point of the normal & the surface
4. mark with crosses the centre of the incident ray, reflected ray & refracted ray
5. connect the crosses with a straight line 6. remove the block & draw a straight line connecting the incident ray with the refracted ray to show the ray that travelled through the block
6. measure the angle of incidence, reflection & refraction
7. repeat using blocks made from different materials, keeping the angle of incidence the same

Question 9

describe a method to investigate how the type of surface affects the amount of IR radiation absorbed or emitted

Answer 9

1. place an infrared detector in line with & 20cm away from the leslie cube & record the initial temperature of the surface
2. a leslie cube has different types of surfaces e.g. matt black, shiny black, matt white, shiny white
3. boil water in kettle & pour it into leslie cube
4. measure initial temperature of water
5. measure the temperature of the surface every 30s for 5 minutes
6. rotate the leslie cube so a different surface is in line with the ir detector & repeat
7. plot a graph for each surface & compare
8. more ir radiation is emitted from black surfaces than white surfaces & from matt surfaces than shiny surfaces