First Semester 7th Grade Science Review Flashcard

Front

What evidence supports the theory that Earth has changed over time?

Back

Fossil records provide evidence of past life forms and environmental conditions, indicating that Earth has undergone significant changes over time.

Front

Heat always travels from _____ to ______ objects.

Back

Hot to cold. Heat energy naturally flows from warmer objects to cooler ones until thermal equilibrium is reached.

Front

What causes convection currents?

Back

Convection currents are caused by the movement of hot magma rising and cool magma sinking, creating a cycle of movement due to temperature differences.

Front

What does REACT mean in a chemical context?

Back

To go through a chemical change, indicating that substances interact to form new substances.

Front

Calculate the speed of an object that travels 150 meters in 30 seconds.

Back

5 m/s. Speed is calculated by dividing distance by time (150 m / 30 s = 5 m/s).

Front

What is a fossil?

Back

A fossil is the preserved remains or traces of ancient organisms, providing insight into the history of life on Earth.

Front

Define convection.

Back

Convection is the transfer of heat through fluids (liquids and gases) caused by the movement of the fluid itself.

Front

What is the principle of thermal expansion?

Back

Thermal expansion is the tendency of matter to change in volume in response to a change in temperature, typically expanding when heated.

Front

What is the difference between a physical change and a chemical change?

Back

A physical change alters the form or appearance of a substance without changing its composition, while a chemical change results in the formation of new substances.

Front

What is the formula for calculating speed?

Back

Speed = Distance / Time.