Physics Required Practicals

Variables:

• Control - volume of liquid and energy provided
• Independent - type of liquid
• Dependent - temperature change

Steps:

• Place element (heating coil around object) in a beaker filled with water and insulate it to prevent energy loss
• Turn on the electric heater for 1 minute and measure the start and end temperatures
• Measure the voltage and current of the heater and calculate the power (P=IV)
• Repeat experiment for different objects
• Calculate the specific heat capacity using the equation on the formula sheet

Hazards:

• Heater gets hot
• Liquids can boil and spit - wear safety goggles

Variables:

• Control - times when temperature is measured, volume of water and insulation thickness
• Independent - type of insulation
• Dependent - temperature

Steps:

• Wrap 4 test tubes in different insulation and fill with hot water
• Measure start temperature, start the stopwatch and measure temperature every minute for 10 minutes
• Plot results of time against temperature using a coooling curve

Hazards:

• Hot water can scald you
• Allow test tubes to cool before touching, even with no water in them

Factor 1: Length of a wire

Variables:

• Control - current
• Independent - length of the wire
• Dependent - voltage

Steps:

• Set up a circuit with a cell, ammeter, voltmeter in parallel to component and a variable resistor
• Pre test the circuit 
• Record voltage and current at different wire lengths
• Use the variable resistor to keep the current constant and calculate resistance

Hazards:

• Avoid touching wire - very hot
• Use low voltage and keep the current low

Factor 2: Series and parallel

Variables - same as factor 1

Steps:

• Set up series circuit with 2 resistors
• Record current and voltage readings and calculate total resistance
• Set up parallel circuit with 2 resistors
• Record current and voltage readings and calculate total resistance
• Compare total resistance of series circuit with the total resistance of the parallel circuit

Hazards - same as factor 1

Variables:

• Control - temperature of the circuit and component
• Independent - potential difference across the component
• Dependent - current through the component

Steps:

• Set up a circuit with a variable resistor, cell, ammeter and a voltmeter parallel to the component
• Use the variable resistor to adjust the p.d across the component
• Measure the voltage and current 3 times to calculate the mean
• Repeat for other components ( filament lamp, diode or resistor)

Hazards:

• Filament lamp can get hot - high currentb through it
• Bulb may blow when too hot

Variables:

• Control - temperature
• Independent - material being tested
• Dependent - volume and mass

Steps:

• Record height of water and mass of solid/liquid being tested
• Add solid to displacement can - the water displaced is the volume
• Add liquid to displacement can - the water displaced is the volume
• Measure volume of regular solid - l x w x h - and measure the mass
• Calculate density for all 3 materials

Tips:

• If solid is less dense than water, there will be no displacement - floats on water so no water is displaced - volume is not given so density cannot be calculated

Variables:

• Control - material the block is made from
• Independent - angle of incidence
• Dependent - angle of refraction

Steps:

• Set up equipment using a ray box, pice of card and a glass block
• Draw around block to keep it in the same place and mark position of light ray at start and end
• Remove block and connect dots to show light ray
• Add normal lines and measure the angle of incidence (reflection) and refraction
• Repeat for a range of incidence angles
• Repeat with different transparent blocks

Variables:

• Independent - force on the spring
• Dependent - extension of the spring

Steps:

• Set up equipment with a clamp stand holding a spring holding a mass holder
• Add 100g (1N) to the mass holder
• Measure the extension of the spring and record results (new length - original length)
• Repeat for masses from 1N to 10N (200g,300g,400g,500g,600g,700g,800g,900g,1000g)

Tips:

• The extension is not the whole length, it is the new length subtract the original length
• Adding too many masses can stretch the spring too far and it will not return to its shape (deformed)

Variables: (depending on what is changed)

• Control - force/mass
• Independent - force/mass
• Dependent - acceleration

Steps:

• Set up equipment with a trolley, light gate, pulley and hanging masses conencted
• Release trolley and use light gate to calculate velocity and stopwatch to calculate time to calculate acceleration (acceleration=change in velocity/time)
• Rpeat using various masses

Tips:

• Repeat results to improve the accuracy of the investigation

Variables:

• Control - water depth

Steps:

• Time how long one wave takes to travel across the tank and calculate the wave speed (S=D/t)
• Count number of waves passing a fixed point in a second to calculate frequency
• OR calculate frequency using formula ( frequency=wave speed/wavelength)
• Estimate wavelength suing a ruler
• Use a stroboscobe to make same meaurements and compare accuracy of results

Tips:

• Stroboscope improves accuracy
• Projecting a shadow can make wavelength measurements easier to take and improve the overall accuracy of the experiment

Variables:

• Control - volume of water and start temperature
• Independent - colour of boiling tube
• Dependent - temperature

Steps:

• Take four boiling tubes with different colours (matt black, gloss black, white, silvered)
• Pour hot water into tubes and measure the start temperature of each
• Measure the temperature of each tube every minute for 10 minutes
• Tube that has the greatest temperature change emits infrared energy the quickest

Tips:

• Evaporation can cause cooling. Block the top of each tube with a bung or wool to minimise this