If you want to teach about cause and effect in science, focus on matching your lesson to the science curriculum of 6th, 7th or 8th grade. For example, 6th grade physical science focuses on the interactions of science and matter, such as the law of gravity. A lesson that uses the law of gravity as a teaching tool might start with having everyone in the class drop a book onto the floor, followed by a prediction of what happens when you drop a feather, a piece of paper and a rock. At the end, teach about the law of gravity and wind resistance, and how we use cause and effect to predict the behavior of dropped objects.
The curricula of 7th and 8th grade social studies often focus on American history and government. You can use both of these subjects to teach the nature of cause and effect.
For example, if you instruct a history class that covers the Great Depression, teach about the causes of that historic period, including installment purchases on stocks, the increase of available credit to the common man and the domino effect of stock selling. After the student learns about the various causes of the Depression, instruct him to create theoretical prevention methods, followed by a review of how he essentially blocked the causes from creating their effects.
Perhaps one of the most important subjects for 8th graders is life and study skills, which you can easily convert into a lesson on cause and effect. Have the students write down dreams for the future, such as a nice house or to have a big family. Then teach about the relationship between income earning and various college degrees. Move backward from a Ph.D. to a Master's degree to a Bachelor's and finally to a high school diploma. After plotting your chart backward, show how poor study skills in 9th grade can lead to not achieving future goals. Complete the lesson with a short essay in which students write how their current study skills predict a specific future.
In addition to scholastic studies, you can also use the arts to physically demonstrate cause and effect. In a video class, for example, have the students film a simple, quick process, such as the popping of a balloon. Show the students how to slow down the film and print five different frames, each demonstrating a different link in the chain of cause and effect.