Required practicals paper 2 Flashcards
Describe how to investigate the relationship between the extension of a spring and the force applied to it
- Set up the equipment as shown in the diagra
- Use a 50cm ruler to measure the length of the spring when there is no mass applied to it
- Hang a 100g (1N) mass off the spring and mesasure the length using a 1m ruler. Record the result in a table
- Calculate the extension of the spring using the formula:
extension = extended length - original length
- Repeat the experiment a further 7 times, increasing the mass by 100g each time, covering a range of 200g to 800g
- Repeat the experiment 3 times and take an average of the extension for each mass. Make sure you use the same spring for each experiment
- Plot a graph of extension (y-axis) against force (x-axis)
- The spring constant of the spring can be found by using the formula:
Spring constant - 1/gradient
Independent variable
The force on the spring
Dependent variable
the extension of the spring
Control variable
The spring - springs with different spring constants will have different extensions for any given force
Explain how to use a trolley and light gates to investigate the effect of force on acceleration
- Set up the equipment as shown in the diagram
- Set up the datalogger and light gate to read the acceleration of the trolley using the double interupt card
- Place 7x 100g masses on the trolley
- Place a 100g (1N) mass on the end of the pulley
- Let go of the masses and trolley and measure the acceleration of the trolley as it passes through the light gate
- Repeat the experiment moving one mass from the trolley to the weight stack each time, do this for a range of 100g to 800g, increasing in intervals of 100g each time
- Repeat the experiment 3 times and take an average
- Plot a graph of acceleration (y axis) against force (x axis)
- the mass of the trolley can be found from the formula
mass = 1/gradient
Independent variable
The force on the trolley
Dependent variable
The acceleration of the trolley
Explain how to use a ripple tank to measure the speed of a wave in water
- Set up the equipment as shown in the diagram
- Set the motor so that it is producing low frquency waves
- Use the meter ruler to measure across 5 waves. Divide this length by 5 to find the wavelength of the waves
- Use a stopwatch to cont the number of waves that pass a point in the ripple tank in 10 seconds. Divide this number by 10 to find the frequency of the wave.
- Use the equation
Wave speed = frequency x wavelength
to calculate the speed of the wave
- Repeat the experiment 3 times and take and average
Explain how to measure the speed of a wave on a string
- Set up the equipment as shown in the diagram
- Adjust the frequency of the generator until a standing wave is created
- Measure across a number of nodes using a meter ruler and count the number of gaps between the nodes
- Devide the length by the number of gaps, then multiply by 2 to find the wavelength of the wave
- Use the equation
wave speed = frequency x wavelength
to find the speed of the wave
- repeat the experiment 3 times using different frequencies of standing waves and take an average to find the speed of the wave on the string
Independent variable
Frequency of standing wave
Dependent variable
Wavelength of the wave
Control variables
The string thickness - thicker string gives a slower speed
The string tension - a string with more tension will create a faster wave speed
Explain ho to use a glass block to investigate the effect that changing the angle of incidence of a light ray has on the angle of refraction
- Set up the equipment as shown in the diagram. Ensure that the normal is drawn at right angles to the surface. Measure this with a protractor.
- Shine the light with an angle of incidence of 10˚ measured to the normal. Mark the angle of refraction then remove the block and measure the angle of refaction with a protractor.
- Repeat the experiment changin the angle from 10˚ to 50˚, increasing the angle of incidence by 5 degrees each time
- Repeat the experiment 3 times and take an average
- Plot a graph of angle of incidence agains angle of refraction
Independent variable
The angle of incidence
Dependent variable
The angle of refraciton
Control variables
The glass block - changing the material will change the agle of refraction for any given angle of incidence
The direction the light is shone - shining the light from air to glass (bends towards the normal) produces a different relationship to when you shine the light from glass to air (bends away from the normal)
Explain how to use two tin cans to investigate the effect of surface colour on infrared radiation
- Paint the outside of one can black. Leave the other can with bare metal so that it is silver.
- Fill both cans with water at 70˚C, which has been heated with a kettle than the tmperature allowed to drop to the correct temperature
- Use a thermometer to measure the starting temperature of each of the cans and then start a timer on a stopwatch
- Measure the temperature of each of the cans every 2 minutes for 16 minutes
- Repeat the experiment 3 times and take an average
- For each material plot a graph of temperature against time, the best emitter of infrared radiation will be the material with the steepest gradeint
Independent variable
The colour of the surface of the cans
Dependent variable
The rate of heat transfer
Control variable
Temperature of the environment - changing the temperature of the environment will change the rate of enrgy transfer by changing the size of the temperature gradient
The material of the cans - changing the material of the can will change the rate of heat transfer
Explain how to use a Leslie cube to compare the rate of infrared emission by different types of surface.
- Set up the equipment as shown in the diagram
- Fill the leslie cube with water that has been boiled in a kettle
- Use an infrared camera to look at the intensity of infrared radiation given off by each surface
Explain how to investigate the effect of aparrent weightlessness on the human body
- Pay £20 million to the european space agency
- Spend 2 years training as an astronaut
- Travel to Russia and take a rocket up to the international space station
- Experience aparrent weightlessness
