Labs

  • All lab from 1-7 are expected to be completed for Thursday 13th February.


Below is lab #4


Date:                     14th January 2014
SBA no.:               4
Title:                      Refraction of Light: Glass Block
Aim:                       To investigate the relationship between the angle of incidence and the angle of refraction for glass

Apparatus:          Glass block, ruler, plain paper, protractor, 4 optical pins
Diagram:

Procedure:
1.       Place the glass block in the centre of the paper and draw the outline of the glass block using a sharp pencil.

2.       Use the protractor to draw in a normal on the middle of the long side of the block. Label the intersection of the normal and the glass block as point O.

3.       Use the protractor to measure out and draw in angles of incidence, i, of 10°, 20° up to 60°. Extend the lines to the edge of the paper.

4.       On the 10° line, place two pins A and B upright, so that A is as close to the block as possible, and B is as close to the edge of the paper as possible.

5.       Looking through the glass at the images of A and B, turn your head in the position where the image of B is directly, behind the image of A. Place a pin C close to the block so that it is in line with the images of A and B.

6.       Place a fourth pin D close to the edge of the paper so that it is in line with C and the images of A and B.

7.       Remove the pins and place an X over the holes for pins C and D that have the correct alignment. Remove the block as well.

8.       Draw a line through the pin holes and extend it back to the glass block (point R). This represents the emergent ray.

9.       By connecting point O to point R, draw in the refracted ray. Draw arrows on incident and emergent rays indicating the direction in which the light travels. Use the protractor to measure the angle if refraction, r, and its corresponding angle of incidence, i.

1.   Repeat the procedure for all angle of incidence drawn.

Results:
Record your answers as shown in the table below.
Angle of Incidence
Angle of Refraction
Sin i°
Sin r°

Data Analysis:
1.       What is refraction?
2.       Do your observations show that light is refracted? Justify your answer.
3.       The last column in the table gives the results for . What do these values represent?
4.       Use your data in the table to find the average refractive index of glass.
5.       The refractive index of glass is known to be 1.5. Do your results support this? If not, suggest a reason why.
6.       State Snell’s Law.
7.       Do your results support Snell’s Law? Justify your answer.

Conclusion:
Write a suitable conclusion based on your aim.


Below is lab #5


Date:                     21st January, 2014
SBA no.:               5
Title:                      Investigating Magnetic Fields
Aim:                       To map the magnetic field around and between magnets
Apparatus:          magnets, tacks, paper, iron filings
Diagrams:


Procedure:
1.       Place a sheet of paper over the desired arrangement of the magnet(s) and sprinkle iron filings on the sheet of paper.

2.       Gently tap the sheet of paper until the iron filings form the field pattern.

3.       Draw the pattern of the iron filings observed.

Results:
(Drawings of your observations)

Data Analysis:
1.       What is a magnetic field?
2.       What do you notice about the direction of the magnetic field?
3.       What do you notice about the field pattern at like poles?
4.       What do you notice about the field pattern at unlike poles?

Conclusion:
Write a suitable conclusion which reflects your aim.


Lab #6


Date:                     28th January, 2014
SBA:                       #6
Title:                     Converging Lens
Aim:                      To investigate the nature of images produced by a converging lens
Apparatus:          Converging lens, lens holder, object (cross wires), screen, ruler, light source
Diagram:


Procedure:
1.       Find the approximate focal length of the lens.

2.       Place the object at a distance between O and F and observe the image formed.

3.       Place the object at a distance between F and 2F and observe the image formed.

4.       Place the object at a distance beyond 2F and observe the image formed.

Data Collected:
Record your results in the table below.
Object Position
Real/Virtual
Image Size
Image Size
Inverted/Upright
Between O and F




Between F and 2F




Beyond 2F






Data Analysis: (Answer the question in paragraph form)
1.       Which system shows the principle of
a.       The projector
b.      The magnifying glass
c.       The camera

2.       A person needs spectacles when the light focuses on a point other than the retina. Where must the light focus if a converging lends is to be used to correct the problem?

Conclusion: (Write a suitable conclusion which reflects your aim)

Lab # 7


Date:                     4th February, 2014
SBA no.:               7
Title:                     Principle of Conservation of Linear Momentum
Aim:                      To demonstrate the principle of conservation of linear momentum
Materials:           Newton’s Cradle
Diagram:


Procedure:
1.       Pull the first ball aside and release. Record your observations.
2.       Pull two balls aside and release. Record your observations.

Results:
Record your observations in a suitable manner. Remember, your observations should be written in present tense.
Data Analysis: (Answer in paragraphs)
1.       Explain your observation in procedure 2.
2.       Explain your observations in procedure 1.
3.       What would you expect if three balls were pulled aside?

Conclusion:

What did you learn from the experiment?

SBA #8

Date:                     11th February, 2014
SBA no.:               8
Title:                     Specific Latent Heat of Ice
Aim:                      To determine the specific latent heat of ice
Apparatus:          Ice, water, Styrofoam cup, thermometer, balance, Bunsen burner
Diagram:         
    
Procedure:
1.       Find the mass, mc, of the Styrofoam cup using the balance.
2.       Warm some water in a beaker to about 10°C above room temperature and carefully pour in into a Styrofoam cup.
3.       Find the mass, m1, of the water and the Styrofoam cup.
4.       Measure the initial temperature, θ1, of the water.
5.       Dry some pieces of ice and slowly add them to the water.
6.       Stir until the ice is completely melted and note the final temperature, θ2, of the water.
7.       Find the final mass, m2, of the water in the Styrofoam cup using the balance.

Data Collected:
(Assume the initial temperature of the ice is 0°C)
Specific heat capacity of water = 4 200J kg-1
Mass of Styrofoam cup mc
Initial mass of water and cup m1
Final mass of water m2
Initial temperature of water θ1
Final temperature of water θ2

Data Analysis:
1.       Write an equation which equates the heat loss to the heat gain in this experiment.
2.       How much thermal energy did the original mass of water lose?
3.       What was the gain in energy of the melted ice as its temperature rose from 0°C?
4.       Using your answers above, calculate the specific latent heat of ice.
5.       The theoretical value for the specific latent heat of ice is 334000Jkg-1. Explain any difference between your result and theoretical value.

Conclusion:
Write a suitable conclusion based on your results.

SBA #9

Date:                     18th February, 2014
SBA no.:               9
Title:                     I-V Characteristics of Metals
Aim:                      To investigate the I-V Relationship of a metallic conductor
Materials:           Metallic conductor (resistor), ammeter, voltmeter, rheostat, battery, connecting wires
Diagram:

Procedure:
1.       Set up your diagram as shown in the diagram above with your rheostat at maximum.
2.       Record your readings of current on the ammeter and voltage on the voltmeter.
3.       By moving the rheostat obtain pairs of values of current and voltage ensuring that your values are spread out over the entire range.
Results:
Record your results in the table below:
Current/ I
Voltage/ V



Data Analysis:
1.       Sketch a graph of what you expected to gain as your results
2.       Draw a graph of current against voltage for the metallic conductor using the results you gained from the experiment.
3.       Briefly describe the shape of your graph.
4.       Does your graph reflect your expected results? Justify your response.
5.       What does the gradient of the graph represent?
Conclusion:
Write a suitable conclusion which reflects your aim.


SBA #10

Date:                     25th February, 2014
SBA no.:               10
Title:                     Current in Parallel Circuit
Aim:                      To investigate current following in parallel circuit
Materials:           Rheostat, batteries, switch, connecting wires, 1 ammeter, 10 ohm resistor, 5 ohm resistor, 20 ohm resistor

Diagram:

Procedure:
1.       Set up the circuit as shown in the diagram above, with your rheostat set at maximum.
2.       Place the ammeter in position A and record the reading at this position.
3.       Change the position of the ammeter to B, C, D and E and in turn record the current readings at each position.
4.       Take note of the values of the resistors in branches B, C and D.

Results:
Record your results in a suitable format.

Data Analysis:
1.       In which branch B, C or D is the current the largest? Why is this so?
2.       What is the value of the current entering junction 1?
3.       What is the sum of the currents leaving junction 1?
4.       What is the sum of the current entering junction 2?
5.       What is the value of the current leaving junction 2?
6.       What can you deduce about the current entering and leaving a junction?
7.       By using V = IR, calculate the voltage across each resistor in each branch.
8.       What can you deduce about the voltage across each branch in a parallel circuit?

Conclusion:
Write a conclusion which summarises all you have learnt from these demonstrations.


SBA #11

Date:                     4th March, 2014
SBA no.:                               11
Title:                     Radioactive Decay
Aim:                      To use an analogous system to illustrate the nature of radioactive decay
Materials:           100 coins, large cans with lid
Diagram:

Procedure:
1.       Note the number of Coins present (undecayed atoms) when n=0.

2.       Allow heads to represent a decayed atom and tails to represent an undecayed atom. Place the coins in the can and snap on the lid.

3.       Shake the can vigorously. Then remove the lid and pour out the coins. Record the number of tails i.e. the number of undecayed atoms t for n=1.

4.       Put the number of heads to one side (decayed atoms).

5.       Place undecayed atoms back in the tin.

6.       Repeat steps 3-5 at least 4 times (until n=5).

Results:
Record your data in a suitable table.
Data Analysis:
1.       Plot a graph of the number of throws (n) on the x-axis against the number of undecayed atom (t) on the y-axis.
2.       If your classmates do the experiment, would they get the same results?
3.       If one coin is marked with an X, can we predict when it will decay:
4.       Complete the following statements:
Radioactive decay is said to be random because (a)         and        (b)
5.       Use your graph to estimate at least three values for the half-life. Is it constant?
Conclusion:
Write a suitable conclusion stating what you would have learnt in the lab.


SBA #12

Date:                     18th March, 2014
SBA no.:               12
Title:                     Half-life of Water
Aim:                      To investigate if the half-life of water dripping from a burette is constant
Apparatus:          Burette, stopwatch, water, beaker
Diagram:

Procedure:
1.       Set up the apparatus as shown in the diagram above with the burette filled above the 0cm3 mark.

2.       Adjust the tap so that it is dripping quickly. If necessary, refill the burette above the 0cm3 mark.

3.       Start the stopwatch when the water level drops to the 0cm3 mark.

4.       Record the time t on the stopwatch at every 5cm3 decrease in volume without stopping the stopwatch.

5.       Record the volume of water remaining, V, and the corresponding time, t, noted on the stopwatch until the volume remaining falls to 10cm3.

6.       Repeat procedure without adjusting the tap.

Results:
V/cm3
50.0
45.0
40.0
35.0
30.0
25.0
20.0
15.0
10.0
t1/s









t2/s









t/s










Data Analysis:
1.       Plot a graph of volume against time.
2.       Determine the time it takes for the volume to fall to half for four different values of volume.
3.       Does this system have a constant half-life?

Conclusion:
Write a suitable conclusion stating what you have learnt.

Good luck folks :)

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