 We want to talk about hybridization just a minute. Hybridization means a cross between orbitals. If we just looked at the traditional S orbit, we would expect it to be a little bit closer to the Y. So if these were S electrons, we would expect them to be somewhere like this and the P to be somewhere like that. But when we actually take this molecule and measure the distance from here to here, we find in this tetrahedron, this methane, the distance is the same from here to here, here to here, here to here, and here to here. So what's happened is you've blended the orbitals and not just S orbitals and P, but SP. And we call that an SP3. And you'll see that in your lab report.