Grades 6–8 · 8 connected explanations
Networks, Exchange & Time
Follow signals and responses through machines and human systems. Then compare historical networks, records of years and the longer times of stars and space communication.
Systems
How does a message travel across the internet?
An internet message travels through connected systems rather than one continuous private wire.
Systems
How does a thermostat use feedback?
A thermostat uses a returning measurement to adjust what happens next.
Societies
How can buyers and sellers affect a market price?
Buyers and sellers influence a market through interacting choices.
Societies
How can a central bank’s interest-rate decision affect spending?
Interest-rate decisions can affect spending through several conditional links and delays.
History & Evidence
How could goods and ideas travel farther than one merchant?
Historical trade networks connected many journeys and communities.
History & Evidence
How can tree rings connect wood growth with calendar years?
Overlapping tree-ring patterns can connect a surviving sample with calendar years.
Earth & Space
Why do different stars have different endings?
A star’s mass helps shape a life history on a much longer time scale.
Earth & Space
Why can a Mars rover not answer Earth immediately?
Even a radio message needs time to cross the distance between planets.