Wo researchers are both interested in the relationship between caffeine consumpt

Two researchers are both interested in the relationship between caffeine consumption and activity level for elementary school kids. Each obtains a sample of 20 children.
1.   The first researcher interviews each child to determine the level of caffeine consumption. The researcher then records the level of activity for each child during a 30-minute session on the playground. Is this an experimental or observational study? Explain your answer
2.   The second researcher separates the kids into two roughly equal groups. The kids in one group are given a drink with 300 mg of caffeine and the other group gets a drink with no caffeine. The researcher then records the level of activity for each child during a 30-minute session on the playground. Is this an experimental or observational study? Explain your answer.