Copper (II) sulfate pentahydrate is a crystalline solid with a beautiful bright blue color. Like most sulfate salts, it dissolves well in water. If you want or need to separate copper sulfate from sand -- either as a classroom experiment or because you accidentally mixed the one with the other -- you can take advantage of this compound's properties to take the two apart.
Pour the sand and copper sulfate into one of the two buckets.
Pour water into the bucket until it covers the sand and copper sulfate mixture. The copper sulfate should begin to dissolve; stir if you need to make it dissolve more rapidly.
Place the paper filter in the funnel. Holding the funnel over the second bucket, pour the mixture through it. The dissolved copper sulfate will pass through the filter, while the sand will remain behind. The solution you have in the second bucket contains copper sulfate only.
Copper sulfate is often used dissolved in water to kill fungi or algae. If you need to separate the copper sulfate from the water, evaporate the water by heating the mixture or leaving it out in the sun until all the water evaporates.
Copper sulfate may be poisonous if swallowed; it's also an eye and skin irritant. Take appropriate precautions and never leave copper sulfate where children can reach it.