Science YR8 Flashcards
What are forces?
Just pushes and pulls in a particular direction
What are balanced forces?
Two forces acting on an object can also work against each other if they are in oppoisite directions. If the two forces are the same, nothing will change.
What are unbalanced forces?
If one of the forces is stronger than the other, something will start to move. the forces are unbalanced. If the unbalanced forces are acting on a moving object, the object will change its speed.
What does stationary mean?
Something that is still or not moving
What does steady speed mean?
Something moving at a constant pace.
What are contact forces?
When a force is applied on an object with some sort of contact or touch.
What are noncontact forces?
When a force is applied on an object without any contact or touch.
What is friction?
A force between two surfaces that are sliding, or trying to slide, across each other. It always works in the direction opposite to the direction in which the object is moving. It always slows a moving object down. It also produces heat.
What is air resistance?
A type of friction between air and another material.
What is water resistance?
The friction between your skin and the water particles.
What is gravity?
The force that pulls things to the centre of Earth (and other planets).
What is magnetic forces?
When two magnets are close, they create pushing or pulling forces on one another.
What is floating?
Object that sits above the fluid.
What is sinking?
Object that moves downwards in the fluid.
What is upthrust?
Force of a fluid pushing objects upwards.
What is buoyant?
If the weight is equal to or less than the upthrust, it floats. Things that floats are buoyant.
What are fluids?
Substances that flow- liquids and gases.
What is density?
How hard or soft an object is.
What does physical changes mean?
When a substance changes shape, size and state of the matter BUT the particles themselves do not change only their spacing and movement change.
What does chemical changes mean?
The particles change completely making a new substance.
What is the change from liquid to gas called?
Evaporation
What is the change from gas to solid called?
Deposition
What is the change from solid to liquid called?
Melting
What is the change from liquid to solid called?
Freezing
What is the change from solid to gas called?
Sublimation
What is the change from gas to liquid called?
Condensation
What does pressure mean?
The amount of force (N) pushing on a certain area.
How do you increase the pressure in fluids?
-Increasing the number of particles
-Increasing speed of particles by heating the fluid-gives energy
-Compress-decrease container size
What is the formula for density?
mass / volume
What is the formula for volume?
mass / density