S2 Science Block 1 Test Revision Flashcards
What are forces measured with?
A newton balance/meter (N)
What are forces measured in?
Newtons (N)
Which force is bigger when a hot air balloon is in the air?
The up thrust from the air
Which force is bigger on a rocket at lift-off?
Thrust
What happens when the forces on a substance are balanced?
It is not moving or it is moving at a constant speed
What happens when the forces on a substance are unbalanced?
It is accelerating or decelerating depending on which force is bigger
What is the thrust of a rocket created by?
An explosion of gasses out of the bottom pushes the rocket upwards
What happens to the particles inside a hot air balloon when they are heated?
They get faster and they move further apart, making them less dense than the air outside
What forces are on a skydiver when they jump out of a plane and are they balanced or unbalanced?
Weight and air resistance. The forces are unbalanced because they are accelerating towards the ground
A while after jumping out of the plane the diver starts moving at a constant speed. Which force changed and what type of force is on the diver now?
The air resistance increased and the forces are balanced
What happens when the diver opens their parachute and why?
The diver slows down because the air resistance increased and became bigger than the weight so now the forces are unbalanced
What happens to the diver a while after they open their parachute and why?
The air resistance decreases because the diver slowed down and now the forces are balanced so the diver falls to the ground at a slow constant speed
Why do helium balloons float?
The helium particles are lighter than the particles in the air so the weight is less than the up thrust from the air
What are the forces like when the hot air balloon is moving across the Earth at the same height?
The up thrust decreases and the forces are balanced
What does rate mean?
Speed
What three things can you do to speed up reactions?
Decrease particle size. Increase concentration. Increase temperature
Which reacts faster, hot acid or cold acid
Hot
What type of metal do you use to help experiment on metals and oxygen?
Potassium permanganate
What is magnesium called after it reacts to oxygen?
Magnesium oxide
What metal is most reactive with water?
Potassium
What gas is given off when metal reacts with acid?
Hydrogen
What metal doesn’t react with acids?
Copper
What type of colour is an acid?
Hot
What happens to the pH when water is added to an acid or an alkali?
It goes closer to 7
