Teacher asks three of her students about science, but it doesn't go quite the way she expected

In grade school one day, the teacher decided that for science class she would teach about the elements. So she stood in front of the class and said, "Children, if you could have one raw element in the world what would it be?"

Alec raised his hand and said, "I would want gold, because gold is worth a lot of money and I could buy a Porsche."

The teacher nodded and called on Penny.

Penny said, "I would want platinum, because platinum is worth more than gold and I could buy a Corvette."

The teacher smiled and then called on Jimmy.

Jimmy stood up and said, "I would want silicon."

"Why is that, Jimmy?" the teacher asked.

He responded by saying, "Because my mom has two bags of it and you should see all the sports cars outside our house!"