I've read that along with the moon, the sun also has an effect on our tides. I understand how the moon would have an effect on tides, but I don't quite get why the sun would. According to my physics book, when something is in orbit, it's really just in free fall around the thing it's orbiting. Here's what confuses me: if the earth is in orbit around the sun, then isn't the entire earth already being acted on by the sun's gravity? And therefore the oceans wouldn't be affected differently in relation to the rest of the earth, since it's all falling together? Think about if you were in an elevator on the top floor of a skyscraper and the cable snapped, sending you into free fall. On the inside of the elevator, since gravity is accelerating everything at the same rate, from your perspective nothing would accelerate towards the floor of the elevator unless acted on by a force different from the earth's gravity. Objects would just seem weightless, and there would be no pull from gravity towards the floor, since in reality the floor would be accelerating along with everything inside. So why is it that when the earth is in free fall around the sun, that the sun would have an additional pull on the earth's oceans, if they too are in free fall along with our planet? I'm guessing that it has something to do with the earth being so large in diameter that different parts of it are being pulled on with noticeably more force by the sun's gravity than others (since they're closer)? This concept also confuses me as to what the implications of this are. Hopefully I've articulated why I'm puzzled by this well enough that people who know why this is the way it is can at least understand how I could be confused. I appreciate any responses.