Why don’t oil and water mix? Water molecules are polar, which means each one has both a positive and negative charge, kind of like a magnet. So, the positive ends stick to the negative ends forming bonds that make water. Oil, on the other hand, is nonpolar, meaning they don’t have either a positive or a negative charge. The only way for oil and water to “connect” is by whisking or shaking them together to break down the liquids into very tiny droplets.