burning of a candle maybe considered as showing physical and chemical changes occuring simultaneously ?
When candle burns, both physical and chemical changes take place.
On burning, the candle wax melts but can be solidified again on cooling.
This shows that melting of wax is a physical change.
The burning of candle also produces light and carbon dioxide.
Hence, it is also a chemical change.
that is : the wick burns, or heat + oxygen + wax = Carbon dioxide, soot, light and smoke.