Wendy wants to know if a new sports drink improves physical performance. The number of push-ups each participant can complete in 1 minute is recorded first. The participants are then given 8 ounces of the sports drink, and the number of push-ups completed in 1 minute is recorded again. Wendy finds that the number of push-ups completed is less after consuming the new sports drink. This finding is likely the result of a effect.

Juanita and sam attend a beach party and notice that the local beach appears to have a great deal more trash washed up on shore than it did when they were young. the water doesn't appear nearly as clear, and there seems to be less evidence of small water creatures living in the shallows. an afternoon at the local library convinces them that one major cause is the new factory nearby. after some discussion, they decide their next step should be identifying the cause of the changes identifying the problem picketing the guilty factory lobbying their elected representatives to complain about the problem talking to a local environmental group about solutions