Make two pendulums of the same length with the help of thread and two nuts. Tie another thread in the horizontal position. Tie the two pendulums to the horizontal thread in such a way that they will not hit each other while swinging. Now swing one of the pendulums and observe. What do you see?

Apparatus: Bars of stainless steel, aluminium and copper, a candle, a burner, pins, etc. : Procedure: Take stainless steel (or iron), copper and aluminium bars, each about 30 cm long and having the same shape. Apply wax spots with the help of candle at a distance of 2 cm from each other on all the three bars. Stick a pin in each of these spots so that it is upright. Now insert the ends of all three bars into a flame at the same time. for a while. What do you see? From which bar do the pins start falling first? Why?

Try this. Draw a cage on one side of a cardboard' and a bird on the other side. Hang the cardboard with the help of a thread. Twist the thread and leave it. What do you see and why?

Take two rubber balloons. Fill one with water and blow air into the other. Now prick both balloons with a pin. What do you observe ?

Rub one end of a glass rod against a silk cloth. Due to the rubbing a small charge will get transferred from one object to the other. As a result both the objects will become somewhat charged. Suspend this rod freely in air with the help of a thread. Now charge another glass rod in the same manner and bring it near the suspended tod. What do you see?

Answer the following questions:Make two sufficiently long, identical tubes out of a cardboard. Arrange them on a table, in front of a wall as shown in figure . Place a clock near the end of one of the tubes and try to hear the ticking of the clock at the end of the other tube by placing your ear there. Adjust the angles of the two tubes till you can hear the sound very clearly Measure the angle of incidence theta_1 and the angle of reflection theta_2 . Try to see if they are related in any way. In the experiment, what will happen if you lift one of the tubes to some height?