The correct answer is 3 or three !!!
Why ?
Because : The burning of gas in the Bunsen burner, lighting of the splint, and ignition of the cracker are all chemical changes. The heating of the water is a physical change.
Justin Bleeber noticed almost 4 chemical changes while conducting his experiment with a soda can. He noticed chemical changes in cracker burns when it heats the water in a soda can. He observed the chemical change when the waves of the gas are seen coming out on the top of the can. He also observes changes while he uses the flame from Bunsen burner to light a wooden split.
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