If there's just some barium put in an aqueous solution, then it should be something like this.
It's a mixture of a solution and an insoluble solid, so the easiest way to go is through filtration. (Also, I'm assuming the barium is cut into very small chips.)
In a line, simply filter the solution using a folded filter paper in a funnel, collect the residue in a beaker or flask, rinse it with distilled water and let it dry. (Or simply filtering it could be enough, depending on how far your teacher wants you to go.)
Stuff needed:
>filter paper (for separating the solid from the solution)
>funnel (to hold the filter paper)
>beaker or flask (to hold the filtrate)
>distilled water (to rinse the solid)
>spatula (to scoop up the solid)
Procedure:
>Fold filter paper and line the funnel with it. Place the funnel in the flask or beaker.
>Pour solution in. Then add water (I think using tap water might be fine in this case, but you can use distilled water if you'd like) to wash out the container with the solution of any solid you may have not gotten in the first try. Alternatively, you could use a spatula to spoon it onto the filter paper.
>Once everything has been filtered, pour some distilled water on the residue on the filter paper to wash away the solution.
>Take out the filter paper, open it up and let it dry.
This can be used in real life in many occasions. For example, when you make tea, you need to filter the leaves out. Or when you cook the pasta, you put it in a sieve to separate the pasta from the water. Or when you fish using fishing nets, you "filter" the fish from the water.
