Is there a way to invest money that is equivalent to betting that the price of oil will go up?

If yes can you explain how to do it in a very basic way. Thanks.

Yeah sure, you could buy oil futures. A futures contract is a type of derivative instrument where two parties agree to transact a set of physical commodities (say oil) for future delivery at a particular price. So the price is set now for delivery in the future. So let's say it's october now and you purchase a crude oil futures contract for delivery in january '08 for $96. Let's also say you have an expectation that oil prices will skyrocket by jan '08.

Fast forward to Jan '08. Indeed prices are currently $116 (for example) per barrel. Since you're just a speculator and don't want a barrel of crude oil to physically land at your doorstep, you decide to sell that contract to another player in the market for $116. You've made a profit by betting that the price of oil will go up!

Having said that, futures are complex and are not for everyone. The profit u make also depends on margin, which is better kept for another question.