Changes in Matter
This type of change happens when ice melts into water.
Physical Change
A horizontal line on a distance-time graph shows this.
Sound is produced when an object does this.
vibrate
The part of the ear that vibrates first when sound enters.
eardrum
CH₄ + O₂ → CO₂ + H₂O:
CH₄ and O₂ are called this.
reactants
A reaction where new substances are formed.
Chemical Change
The formula to calculate average speed.
distance / time
The unit for measuring loudness.
decibel (db)
Astronauts need these to talk in space.
radios
CH₄ + O₂ → CO₂ + H₂O:
CO₂ and H₂O are called this.
products
This is why a straw appears bent when placed in water.
refraction
If a car travels 150m in 30 seconds, its average speed is this.
5 m/s
This wave behavior causes an echo.
reflection
These particles move when sound travels through air.
What are air particles?
A loud sound wave has a high value of this.
Amplitude
This type of change happens when paper is burnt.
Chemical change
A straight diagonal line going up shows this.
constant speed
If the frequency of a wave increases, this happens to the pitch.
becomes higher
This part of the ear helps turn vibrations into signals to the brain.
What is the cochlea? (or inner ear)
A low-pitched sound has a low value of this.
frequency
This is the key difference between a chemical and physical change.
chemical change creates a new substance, but a physical change does not
This is what a steeper line on the graph tells us.
faster speed
Sound cannot travel in this environment.
vacuum (like space)
Without this, sound cannot travel.
What is a medium (solid, liquid, gas)?
A soft material like foam causes this type of sound behavior.
absorption