Answer this activity please...
14.2 Place a candle in a beaker or wide - mouthed bottle and light it. Light an incense stick and take it to the mouth of the above bottle (Figure 14. 1).
Which way does the smoke flow when the incense stick is kept near the edge of the mouth?
Which way does the smoke flow when the incense stick is kept a little above the candle?
Which way does the smoke now when the incense suck is kept in other regions?

a) The smoke is pulled inside the beaker when the incense stick is kept at the mouth of the beaker.
b) The smoke moves upward when the incense stick is kept above the flame because hot air from the flame rises upwards.
c) The smoke flows towards the bottom of the flame when the stick is kept at the edge as air is required for combustion of wax.
d) From the experiment we can conclude that there is convection in air, the cold air is taken inside the beaker and hot air is given out.