Okay, imagine teams of detectives solving crimes. The FBI mostly focuses on law enforcement and the investigation of Federal crimes, such as kidnapping or terrorist acts. They use a lot of techniques like gathering evidence, conducting interviews, and surveillance. They also have a special division that handles things like fingerprints and DNA analysis.
The CIA, on the other hand, mostly deals with 'spying' to protect the country's interests. This means gathering information about other countries, political groups, and individuals who may pose a threat to the United States. They use techniques like hacking, intercepting secret messages, and secret agents.
The CIA also has a lot of scientists working for them, and these scientists come up with really cool gadgets and tools that help them gather their information. For example, they might use a tiny camera that fits in a pen to take secret pictures or a satellite that can take pictures of Earth from space.
So, while both the FBI and CIA need to use science to get the job done, the CIA needs it a bit more because they have a lot of information to collect and analyze from all over the world, and they need scientists to help make their tools and technology to get that information. That's why the CIA is more "sciency" than the FBI!