One possible way to separate wooden marbles from glass marbles is by using a magnetic field. Since wooden marbles are typically not magnetic, while glass marbles are also not magnetic, one can use a strong magnet to attract and separate the wooden marbles from the glass marbles. The magnet will attract the wooden marbles while the glass marbles will remain unaffected and can be easily sorted out.
Chromatography
Well, darling, if you want to separate marbles and pebbles, you can simply use a sieve or mesh screen with holes big enough for the pebbles to pass through but small enough to catch those sassy marbles. Just give it a good shake and watch those marbles roll into one pile and the pebbles into another. Easy peasy lemon squeezy!
Either: 1) Find the radius of each marble and thus their volume through V = 4/3 x pi x r^3 and then add the volumes up. or 2) Put all the marbles in a measuring jug and fill it up to the top. Pour the water into a separate container and empty the marbles out of the jug. Pour the water back into the jug. Thus: Volume of water with marbles - volume of water without the marbles = volume of marbles
He will have 13 blue marbles and 10 green marbles.
Separate them by colour
You can separate sand and iron marbles using a magnet. The iron marbles will be attracted to the magnet, allowing you to separate them from the sand.
One possible way to separate wooden marbles from glass marbles is by using a magnetic field. Since wooden marbles are typically not magnetic, while glass marbles are also not magnetic, one can use a strong magnet to attract and separate the wooden marbles from the glass marbles. The magnet will attract the wooden marbles while the glass marbles will remain unaffected and can be easily sorted out.
A magnet can separate paper clips from marbles in a mixture because paper clips are usually made of metal and are magnetic, while marbles are not magnetic. By using a magnet, you can attract and separate the paper clips from the marbles.
Use a magnet to attract and separate the iron fillings from the marbles, as iron is magnetic while marbles are not. Use a sieve to separate the marbles and iron fillings based on their size differences. The marbles will remain on top of the sieve while the smaller iron fillings will pass through the sieve holes.
using a screen
Visual - the clue is in the question! Or use a magnet, assuming the steel marbles are not of a non-magnetic grade of stainless-steel.
One possible method is to use a magnet to attract and separate the steel ball bearings from the marbles. The steel will be attracted to the magnet and can be easily removed, leaving the marbles behind.
You have to pick them up
That will depend on the size of the styrofoam pieces. If they are significantly larger than the sand, you merely pick them out by hand. If not, then a sieve can be used assuming the sand will go thru the sieve and the styrofoam will be too large to pass through. You need to find a sieve with the right size holes. Another way is to add acetone and the styrofoam will dissolve, and the sand will stay behind, but this technique doesn't give you the styrofoam back again.
Examples: colloidal gold, milk, mist, styrofoam, fog, mayonnaise, cosmetic gels etc.
Put them in water.