Required Praticals Flashcards
Describe an experiment to look at specific heat capacity.
Measure the mass of a block with two holes in it. Then wrap it in an insulating layer to avoid losing heat energy and place a thermometer and a heater in it. Measure the temperature of the block and turn the heater to 10V. The current does work, causing electric energy to travel to the block and be converted into thermal energy, heating the block. Measure the current and temperature every minute for 10 minutes. Use the equations P=IV and E= Pt to work out the figures you need for ΔΕ=mcΔθ, and rearrange it so that heat capacity is 1/(gradient x mass of block) after you have put it onto a graph.
Describe an experiment to look at thermal insulators / insulating materials.
Boil water and pour a safe level into a beaker with a lid. Record the mass and measure the initial temperature. Then seal the container and wait for 5 minutes before recording the temperature again. Allow the container to cool and repeat, but using materials such as newspaper. The less energy lost, the better insulator. You should also find thicker materials should be better at keeping it hot.
Describe an experiment to investigate factors affecting resistance in a circuit.
Create a series circuit with an ammeter (in series) and a voltmeter (in parallel), with a ruler with a piece of wire, two batteries and a switch. Attach one crocodile clip to the 0cm on the ruler and the other 10cm away. Record this and turn on the circuit, recording the results on the ammeter and voltmeter. Repeat this, and then use R=V/I (from VIR) to plot a graph. It should show a straight line from 0 showing direct proportionality. If not, you could have made a systematic error.
Describe an experiment to look at different component’s I-V characteristic.
Create a series circuit with a component, cell, variable resistor, ammeter (in series) and voltmeter (in parallel). Take a component and change the variable resistor, recording the changes in I and V. Swap the wires connected to the cell so the direction of the current changes and repeat. Plot a graph. The 3 components are an ohmic conductor (which goes straight through 0 in a straight line), a filament bulb (which curves slightly at the ends but looks similar to an ohmic conductor) and a diode (which stays on 0 before the graph is positive and then shoots up).
Describe an experiment to investigate resistance.
For resistors in series, create a circuit with a cell, ammeter and resistor. Look at the p.d of the cell and then measure the current on the ammeter. Keep adding resistors and record how current changes. For resistors in parallel, create a parallel circuit and keep adding resistors in parallel. Then use the equation R = V/I to find the resistance as the resistor number increases from one to four. On a graph, adding resistors in series should show that adding resistors decreases the current. Adding resistors in parallel should increase the current and decrease the resistance, so the graph curves down.
Describe an experiment to investigate the relationship between force and extension in a spring.
Put a spring on a clamp stand, measuring it’s length in mm. Add mass, allow it to settle and measure the new length. Subtract the old length from the new length to get the extension. Repeat this at least 6 times and plot a force-extension graph. If you reach the limit of proportionality the graph will curve.
Describe an experiment to investigate how mass and force affect acceleration.
Set up a trolley with known mass with a piece of card on it, a pulley with mass and a light gate connected to a computer. Place the trolley behind the start line and release it. Repeat this two or three times to get an average acceleration.
Describe an experiment to measure water ripples (waves).
Use a signal generator attached to a dipper on a water tank to create waves of a set frequency. Using a lamp you can view these and measure the distance between 10 wavelengths and divide it by 10 to find the average wavelength. Then calculate the wave speed using the equation.
Describe an experiment to investigate the wavelengths on a piece of string.
Using a signal generator, a vibration transducer, string, masses and a pulley, set up the experiment and use the generator to create a frequency of vibration. Measure the wavelength between 4 or 5 waves and divide it to find the average wavelength. Then use the equation to find the speed.
Describe an experiment to investigate transparent objects and refraction.
In a dark room, use a ray box on a piece of paper to shine a light at a transparent rectangle which has been traced around. Trace the incident ray and the emerging ray, then connect them when the rectangle has been removed. Draw in a normal and measure the angles of the incident ray and the emerging ray. Repeat this using different transparent materials.
Describe an experiment to investigate light reflection on different objects.
In a dark room, draw a straight line on a piece of paper and line up an object with this line. Use a ray box to shine a light on this object and trace this line and the reflected line. Draw the normal where the light hits it and measure the angles of the lights. Also note the width and brightness of the reflected ray and repeat this with different objects with different textures.
Describe an experiment to investigate emission using a Leslie cube.
Place a Leslie cube on a heatproof mat and fill it with boiling water. Wait for it to warm up and measure the temperature of the 4 boiling sides, which should all be the same temperature. Hold an infrared detector a set distance from the cube and detect the amount of IR radiation. You should find more from the black surfaces than the lighter surfaces. Repeat this to get an average.
