Practicals Flashcards
(28 cards)
What are the 2 types of errors in an experiment?
Systematic and Random
What is a systematic error?
a consistent error that affects all measurements in the same way, leading to readings that are always higher or lower than the true value
What is a random error?
errors made by the person carrying out the measuring, and are usually down to timing incorrectly, or reading the instrument incorrectly
Give an example of a systematic error?
balance not resetting to 0, staying at 0.02g (zero error)
Give an example of a random error?
Parallax error when reading instrument
What is the aim of the Hooke’s law practical?
To determine the relationship between force and extension for a spring
What are the independent and dependent variables in the Hooke’s law practical?
Independent variable - Applied force
Dependent variable - Extension of spring
What is a control variable for the Hooke’s law practical?
same spring
What is the method for the Hooke’s law practical?
1) attach a clamp to a stand and hang a spring from the clamp
2) measure the length of the spring
3) place 100g weight on the spring and measure its length again
4) keep adding 100g weights till you cannot add more without surpassing the elastic limit of the spring
5) measure length for each time more weight is added
6) to find out extension for each weight, subtract initial length of spring from length with weights
What are the 2 aim of the acceleration practical?
investigate the effects of a varying force on the acceleration of a constant mass
investigate the effects of a varying mass on acceleration caused by a constant force
What are the independent and dependent variables in the acceleration practical?
Independent variable - Applied force.
Dependent variable - Acceleration of the trolley
What is a control variable in the acceleration practical?
the trolley
What is the method for the acceleration practical?
1) measure length of bench and attach trolley with one end of the string with the other end running across the bench pulley
2) attach the weight stand to the dangling end of the string and hold the trolley so the string is taught
3) release the trolley and start timing, stop timing when trolley reaches the other end of the bench
To investigate changing force on a constant mass:
1) add 10g to the weight stand and repeat the experiment
2) keep adding 10g and repeating experiment until you reach 100g
To investigate changing mass with a constant force:
1) add 10g to the trolley and repeat experiment
2) keep adding 10g and repeating till you reach 50g
How do you calculate the acceleration in the acceleration practical?
2*distance / time^2
What is the aim of the ripple tank experiment?
to measure the frequency, wavelength and speed of waves by observing the waves in a ripple tank
What are the independent and dependent variables in the ripple tank experiment?
Independent variable - Frequency of waves
Dependent variable - Wavelength and wave speed
What are control variables in the ripple tank experiment?
Depth of water in ripple tank, shape of ripple tank and the shape of the object creating the waves
What is the method for the ripple tank experiment?
1) fill the ripple tank so the water has a depth of approx. 5mm.
2) place the ripple tank on top of a piece of white paper or card
3) place a wooden rod on the surface of the water and attach it to the low-voltage power supply and motor. Add a lamp to the circuit and hold it above the ripple tank
4) view the wave pattern from the side of the tank, looking through the water
5) to measure the wavelength, place the ruler perpendicular to the wavefronts on the page. Measure across as many wavefronts as possible and divide by the number of waves
6) to measure the frequency, count the number of waves passing a certain point over a given time using a stopwatch
What is the aim of the light practical?
To investigate the reflection of light by different types of surface and the refraction of light by different substances
What are the independent and dependent variables in the light practical?
Independent variable - Angle of incidence
Dependent variable - Angle of refraction to calculate the refractive index
What are 2 control variables in the light practical?
Glass block, light source
What is the method for the light practical?
1) use a slit to produce a thin ray of light from the ray box
2) place the first block of material on the top of a piece of paper and trace around the block using a pencil
3) draw a normal to the block and align the incident ray with the point at which the normal touches the surface of the block
4) draw the reflected ray and the refracted ray. Remove the block and draw a straight line between the point of reflection and the refracted ray on the other side of the block
5) using a protractor, measure the angles of incidence, reflection and refraction
6) repeat the experiment using a new piece of paper for each different material
What is the aim of the radiation and absorption practical?
To investigate how the amount of infrared radiation absorbed or radiated by a surface depends on the nature of the surface
