Sound
Sound travels 2,100m through seawater but only 55m through air at the same frequency. Which medium transmits sound further?
Seawater- It transmits the sound 2,100 m compared with only 55 m through air.
What happens when light bounces off a surface?
Reflection
What is the smallest particle of an element?
An atom
What are the starting substances in a chemical reaction called?
Reactants
What planet is known as the red planet?
Mars
What unit is used to measure frequency?
Hertz (Hz)
What is the name given to light bending as it enters a different material?
Refraction
Is water an element, compound or mixture?
A compound
Is rusting a physical or a chemical change?
What gas do plants absorb during photosynthesis?
Carbon dioxide
What property of a sound wave determines its pitch?
Frequency
Why does a red object appear red?
It reflects red and absorbs most other colours
Which particle is gained or lost when an atom forms an ion?
An electron
State two signs that a chemical reaction has occurred
Examples: Colour change, gas production, temperature change, light or a new solid forming
What is the process called when a substance goes from a liquid to a gas?
Evaporation
What property of a sound wave determines its loudness?
Amplitude
Light travels from air into water. Why does it change direction?
It's speed changes when it enters a material with a different optical density
Write the chemical formula for the following ions:
Mg²⁺ and Cl⁻
MgCl₂
Write the word equation for hydrogen reacting with oxygen
Hydrogen + oxygen → water
Patella
Explain why a tall drum usually produces a lower pitch than a short drum
The taller drum has a longer vibrating air column, producing a lower frequency sound
A light ray hits a mirror at an angle of incidence of 35°. What is the angle of reflection? Explain your answer
35°. According to the law of reflection, the angle of incidence equals the angle of reflection. Both angles are measured from the normal.
Compare an element, compound and mixture.
An element contains one type of atom; a compound contains chemically bonded elements; a mixture contains elements and substances that are not chemically bonded.
Balance the equation H₂ + O₂ → H₂O
2H₂ + O₂ → 2H₂O
Which part of the cell contains it's DNA
Nucleus