Physical vs. Chemical Changes
Ice melting into water — physical or chemical change?
Physical
What is the first step of the scientific method?
Define a problem or ask a question
Increasing temperature does what to most chemical reactions?
Speeds them up
What does the Law of Conservation of Mass state?
Mass is not created or destroyed
What is a scientific law?
A statement that describes what happens in nature
Burning paper — physical or chemical change?
Chemical
What is a variable?
A factor that can change in an experiment
Cooling a reaction usually does what?
Slows it down
When ice melts, does the total mass change?
No — it’s conserved
What is a scientific theory?
An explanation supported by evidence and experiments
Rust forming on a nail — what kind of change is this?
Chemical
What tool helps organize collected data?
Charts, tables, or graphs
Why do higher temperatures cause faster reactions?
Particles move faster and collide more often
In a closed system, if vinegar and baking soda react, what happens to the total mass?
It stays the same
How can science influence government decisions?
Provides data for laws or policies
What evidence shows a chemical change has occurred?
Color change, gas, temperature change, or new substance
What type of variable does the scientist control?
Independent variable
Give an example of a real-life chemical reaction affected by temperature.
Cooking, baking, rusting, etc.
What might make it look like mass is lost in a reaction?
Gas escapes into the air
How can politics or money affect science?
They determine what research gets funded or prioritized
Dissolving sugar in water — physical or chemical? Explain.
Physical, no new substance forms
After analyzing data, what comes next?
Draw conclusions and defend with evidence
How can students test how temperature affects chemical change?
Conduct an experiment using substances at different temperatures and observe reaction speed
How can students prove this law in a lab?
Weigh before and after in a closed container to show mass is the same
Give an example of science helping make real-world decisions.
Climate change, medical research, or public health policies