A person walks 4 m to the right and then turns around and walks 5 m to the left. What distance did they travel?
M

in 1783 cavendish was working with his hydrogen gas and found that when he burned it and condensed the vapor it was water. this was very significant since it disproved the greek theory of elements completely since water was not a simple substance but the product of two gases. it was lavoisier who hearing of the experiment gave cavendish's gas the name hydrogen ("water-producer") and added that hydrogen burned by combining with oxygen and that water was a hydrogen-oxygen combination.

explanation:

practical process described pest part of scientific investigation.

because practical knowledge is powerful then therotical knowledge.