Chemical&Physical changes
What is a physical change?
A change in form or state with no new substance formed
What is speed?
Distance divided by time
What force keeps planets in orbit?
Gravity
What is plate tectonics?
The movement of Earth’s crustal plate
What are producers?
Organisms that make their own food (plants)
What is a chemical change?
A change that forms a new substance
A car travels 100 km in 2 hours. What is its speed?
50 km/h
What happens to gravity as distance increases?
It decreases
What forms when plates move apart?
Ocean basins / mid-ocean ridges
What happens to energy as it moves up trophic levels?
It decreases
Is cutting paper a physical or chemical change?
Physical change
what two measurements are needed to calculate speed?
Distance and time
Why does the Moon orbit Earth?
Earth’s gravity pulls it
What type of plate boundary causes earthquakes?
Transform Boundary
What is an energy pyramid?
A diagram showing energy flow between levels
Name TWO signs of a chemical change
Color change, gas produced, heat/light, precipitate
If distance increases but time stays the same, what happens to speed?
Speed increases
Which has more gravity: Earth or the Moon?
Earth
What happens when two plates collide?
Mountains form or one plate subducts (volcanoes)
What is the main source of energy in ecosystems?
The Sun
Compare physical vs chemical changes
Physical = no new substance; Chemical = new substance formed
Can an object have constant speed but changing velocity?
Yes (if direction changes)
How does gravity control motion in the solar system?
It keeps planets, moons, and objects in orbit
Explain how plate movement can cause BOTH volcanoes and earthquakes
Movement builds pressure → earthquakes; subduction/magma → volcanoes
Why is less energy available at higher trophic levels?
Energy is lost as heat at each lev