HARI SREENIVASAN:

But first: The city of Philadelphia is considering a new, but controversial way of funding early education.

Here's my report, part of our weekly series on education that airs on Tuesday nights called Making the Grade.

In Philadelphia, buying soda has bubbled into a political controversy. To make pre-kindergarten available to all 3- and 4-year-olds, Philadelphia's mayor has proposed a soda tax that requires beverage distributors to pay 3 cents for every ounce of sugary drink sold in the city.