Copper, aluminum, rubber and cotton represent five tons in one hand.
Beans, meal, corn, wheat and fuel oil represent ten tons.
Futures are traded on the futures exchange.
Futures and spot:
Futures are relative to spot. Different delivery methods.
Spot is cash spot, and futures are contract transactions, that is, mutual transfer of contracts.
There is a time limit for futures delivery. Before the expiration, it is a contract transaction, but the expiration date is to cash the contract for spot delivery. Therefore, large futures institutions often do both spot and futures, which can be used for hedging and speculation. Ordinary investors often can't deliver in time, so they have to speculate purely, and the speculative value of commodities is often related to factors such as spot trend and duration of commodities.