Terraforming is changing a planet so it can support earth life including humans. As the atmosphere of Mars is less than 1% of earth it is for earth life just a vacuum. Only some very hardy lichens can survive there.

If you create a vacuum on earth for a high school experiment it would still be denser than the atmosphere of Mars.

To begin terraforming Mars you would have to melt all of the CO2 that is locked into the martian poles and much of the water there. Then plants like algae could transform some of that CO2 to plant matter and oxygen. But there is not enough nitrogen there to make an earth like atmosphere.

Also Mars cannot hold on to an atmosphere for long. It would lose its new atmosphere after a short time, like a few million years.