# Required Practicals

• Created by: harrypj03
• Created on: 05-03-19 13:48
• AQA GCSE Physics Required Practicals
• Specific heat capacity
• The heater increases the internal energy of the body and we measure this using a joulemeter. Measure the temperature of the body (object) at the start and measure the maximum temperature of the body at the end.
• Specific heat capacity = change in internal energy / (mass (kg) x maximum temperature rise (°C) ).
• Insulation
• A vacuum flask keeps drinks hot or cold.There is a vacuum layer (with no air in) surrounded by walls lined with silver.This prevents heat loss to the environment via conduction or convection. However, it is hard to create a perfect vacuum so there may be some particles.
• The silvered walls reduce the heat transferred by radiation.Materials that are poor heat conductors (like rubber) keep the container in position inside the flask.For normal objects, adding more layers of insulation can reduce the heat lost to the environment.
• Resistance
• any suitable value of resistors may be used as long as you have two resistors of the same value. Using wire-wound resistors should alleviate any potential problems with overheating.
• Give students two resistors of the same value and ask them to connect them into the two circuits shown below. By measuring the voltage across the resistors and the current through them (placing the meters in the positions shown in the circuit diagrams) they can calculate the total resistance of the circuit.
• I.V. Characteristics
• set up circuits involving different elements to investigate how the current changes as with the potential difference. There are three parts to this investigation. Characteristrics of a  •lamp    •resistor    •diode.
• Density
• For solids, we can use the Law of Displacement to estimate its volume.This is done using a displacement can, or a graduated measuring cylinder.The volume of displaced water is measured, and this is the volume of the object.
• For measuring the density of liquids, place a measuring cylinder on a balance and set the reading to zero.Pour the liquid into the cylinder and write down its mass and volume. Then calculate the density
• Force & Extension
• Waves
• To produce plain (straight) waves, a wooden rod should be used (usually one of the accessories supplied with the ripple tank). When stationary, the wooden rod should just touch the water surface. The ripple pattern can be viewed either on a large sheet of white card placed on the floor directly below the ripple tank or on the ceiling.
• To achieve the conditions necessary for resonance the following can be adjusted: • the frequency at which the generator vibrates (adjust the frequency of the signal generator) • the length of string allowed to vibrate (move the wooden bridge) • the tension in the string (add or remove masses).
• For a quick demonstration use an elasticated cord attached to the vibration generator. Then simply stretch the cord until it resonates and a standing wave pattern is seen. Students should observe the wave pattern and then decide how the wavelength, frequency and speed should be measured.
• Acceleration
• Students draw straight lines in chalk onto the bench at equally measured intervals to allow the time to travel set distances to be easily recorded. The force is provided by the weight stack, string and pulley. Attach the pulley to the bench at the far end of the track. Hang the weight stack on the string, pass it over the pulley and attach it to the toy car. Select weights that, when added to the end of the string through the pulley will just accelerate the car along the bench.
• To investigate the effect of force on acceleration with constant mass, repeat the experiment with different masses on the end of the string placing the mass removed from the hanger on the top of the car so that the total mass of the car and hanger is constant. To investigate the effect of mass on acceleration with constant force, use the same mass on the string and add different masses to the top of the car.
• Light
• In this experiment, students trace the path of light reflected from and refracted through blocks of different materials. They will use a ray box to produce a narrow ray of light. They will compare the light reflected and refracted for the two materials. The reflected and refracted rays from the ray box will be faint. The experiment will have to be carried out in low light conditions.