HI W., I work with toddlers and when there are 8 in one room, you see a lot of tantrums. Kids this age have really strong emotions, but aren't quite sure how to handle them. Remember, adults know how to handle their feelings, but kids are not born with this knowledge--it has to be taught.
To help your son with his emotions, you can do several things:
1)Decide ahead of time a plan of action for when he gets upset. When he gets upset, follow through with your plan. This will help you to act calmly and not let his tantrum overwhelm you.
2)Think of what your son may need in order to help him learn how to express his emotions. Does he need to just let it out? If so, make sure he is safe and then after he calms down, talk to him about his feelings and validate them. He needs to learn that it is ok to have these feelings, but there are appropriate and inappropriate ways of handling them. Say, "You seemed really angry/mad/sad, ect" Helping him put words to his feelings can make them less confusing and overwhelming to him. He can start to use these words as well--"I'm angry."
3)Help him learn alternate behaviors. "I'm sorry you're angry, but you may not hit me. You can hit this pillow (or throw this ball, or use your words, etc.)." Try to focus on what he CAN do rather than what he can't.
4)This will also help in times other than when he is having tantrums. Focusing on what IS acceptable rather than everything he can't do can prevent some tantrums. "I can't let you have that candy at the store, but we can have a snack when we get in the car." or "We can't play outside right now because it's raining but we can find a fun game inside to play. Let's go outside when it stops raining."
5) Let him express feelings in other ways--pounding on play-dough, running outside, acting things out in dramatic play, using art materials, yelling outside while playing, throwing balls ect. Make sure he has plenty of opportunities to do these things.
6)Whatever you do, do NOT let his negative behavior cause you to give in to what he wants. He will quickly learn that it works and will continue to do it. Be firm with your response and stick to it. Consistency is KEY!
The good news is that the tantrum stage doesn't last too long if you respond appropriately. He will eventually learn that they don't help him get what he wants, and you can help him learn more acceptable ways of handling his strong emotions. That's basically what it is all about --helping him learn more acceptable ways of doing things, not punishing him for not knowing how.
Best wishes! C.