Sand and Water table
Filling, pouring, and dumping are favorite activities for toddlers and all teach cause and effect. Doing these same activities with siblings and friends teach other types of lessons. We were able to get our kids a water/sand table. It came with cups, boats, shovels, and other fun toys. The first lesson they learned was what happens when you dump sand or water (or both) on yourself. This was quickly followed by learning what happens when you do it to your sibling.
Can we make a mess?
Another type of cause and effect we started teaching once the kids turned one when you make a mess, you clean it up. When they dumped out their toys, they got to pick them up again. This required a great deal of one-on-two direct instruction. "Put the truck in the bucket. Put the book on the shelf. Put the ball in the basket." It was extremely slow, but they did learn. Looking back on this a year later, I am happy to say it has mostly worked. They don't always clean up without being told (sometimes they do), but when we tell them to clean up they know what it means. They can clean up all of their toys and books with minimal instruction. By 2 years old they have also learned to clean up as they go for many things.
Splashing each other
The other side of teaching cause and effect is when they learn to control you. Every child does this - they act or react a specific way to get attention. You will see many children fall down, look to see who is watching, and then cry. If you don't react when they fall, they will likely just go on without acting hurt, unless they are truly hurt. Sometimes our kids will fall and get up and keep playing while we are trying to catch them and clean their scraped knees. We try not to play into pity parties. Our kids do know that when Mommy is frustrated, giving her a hug will make it somewhat better. They know how to make us laugh. They have learned that things they cause have an effect on others. While this seems like a simple concept, this is huge when it comes to social development.
Where's the key?
Understanding cause and effect will help children develop socially and develop scientific minds. Play doesn't have to be complicated, but it should be memorable!