Activity

Aim : To investigate the occurence of day and night due to the rotation of the Earth.

Procedure:

1     A globe and an electric torch are used to carry out the activity.
2     The apparatus is set up as shown below.

3     The globe is spinned slowly from the west to the east.
4     The observations are recorded.

Observation:

Inferences:

1     The side of the globe facing towards the torch is lighted. The light represents daytime.
2     The side of the globe facing away from the torch is in darkness. The darkness represents night-time.

Conclusion:

The rotation of the Earth on its axis causes the occurrence of day and night. 

Activity

Aim: To simulate and observe the phases of the Moon

Procedure:

1     This activity must be carried out in a dark room.
2     A stick is pierced through the centre of a polystyrene ball to represent the Moon.
3     An electric torch is placed in the room to represent the Sun.
4     The polystyrene ball is held by the observer at arm's length between the torch and his eyes.
5     The half surface of the ball facing the observer is observed.
6     The observations are recorded in the form of drawings.
7     Together with his arm, the observer turns 45 degree to the left (anticlockwise).
       He observes the surface of the ball facing him and records its apperarance.
8     Step 7 is repeated for all the other positions given in the following diagram.

Inferences:

1     We see different parts of the Moon at different times because the angles between the Moon, the Earth and the Sun are changing all the time.

2     When the Moon is farthest from the Sun, half of the surface of the Moon is illuminated. This is known as the full moon.


Conclusion:

The phases of the Moon are caused by the movement of the Moon around the Earth and its changing position relative to the Sun.

More exercises- paper I

Choose the best answer.

1     The figure below shows one of the phases of the Moon.

        The name of the phase is ____ .

        A     waxing crescent                   B     first quarter      

        C     new moon                           D     full moon


2     The figure below shows sunlight falling onto the surface of the Earth.

         









       Which of the places labbelled P, Q, R and S is experiencing dawn?

       A        P                                       B       Q                   

       C       R                                        D        S



3      The figure below shows the Earth and its natural satellite.

       The time taken for the satellite to move around the Earth once is ______ .

       A       a lunar year                      B     a solar year        

      C      a lunar month                     D     a solar month


4     The figure below shows two phases of the moon.

       What are the names of the phase L and phase M?

                L                                          M

       A     first quarter                         waxing gibbous

       B     waxing gibbous                    first quarter

       C     waxing crescent                   first quarter

       D     waxing crescent                   waxing gibbous

5     The figure below shows the various positions of the Moon in its orbit around the Earth.

   








        Which position, J, K, L or M , is the position of a new moon?

       A      J                                        B       K                         
 
       C      L                                       D       M





     Answers:

     1    A                  2     B                  3    C                  4    D                   5     C