What did I learn? Scientific Knowledge - Physics 1
Forces
Interactions that have an effect on an object
Push/ Pull or together - Twist
They can be contact (Have to touch the object) or Non Contact (No touch required)
Cause an object to change speed, shape or direction
Examples of Forces
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Gravitational (Gravity)
Magnetic
Frictional
Electrical
Measuring Forces
Measured in Newtons (N) after Isaac Newton. When naming units, we use a capital letter if it is named after someone.
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Newtons are measured using a Newton Meter
(Also called a Spring Balance or Newton Balance - See Below)
Isaac Newton EXPLAINED Gravity
When using a Newton Meter it is important to use the correct scale as sometimes they have 2
Atoms
Everything is made from atoms arranged in different ways
From my previous knowledge I know that atoms are arranged in an a cloud model. Within this model electrons fill the space between the nucleus, but between the Nucleus and Electrons there is NOTHING and therefore atoms are largely made of space.
Everything is made from atoms, but atoms themselves are mostly made from space. This a very interesting and difficult concept to get your mind around, and is not one that we would teach to Primary children!
This is what makes different materials have different properties
Example: Solid, Liquids, Gasses
Particles in solids are very close together
Particles in liquid have a bit of space between them
Particles in gas have lots of space between them
Gravity
Mass and Weight
When Measuring mass we use a BALANCE, not a scale!
The standard units of mass are Kilograms (kg)
This effect of Gravity (pulling force) acting on an object is called it’s WEIGHT, measured in Newtons (N)
WEIGHT (W) = mass (m) x acceleration due to gravity (g).
On earth, the gravitational force, g is taken as 9.81 N/kg.
W = m x g can be used to work out the weight of an object. The value of g is the same everywhere on Earth but it is different on other planets or the moon.
Weight is not purely dependent on gravity, other forces acting on an object also create an effect. This can be seen with buoyancy in water, for example.
Friction
No surface is perfectly smooth, even if it may appear this way.
Friction is a force that acts against motion
When 2 surfaces come together they will catch against each other and slow down movement
The size of the gravity force, g, depends on the size of the planet you are on. The moon for example is smaller than the earth so g is smaller and this is why you can jump higher on the moon
When a lift moves downwards with you inside you will feel lighter. You will feel heavier when the lift moves upwards
All surfaces have a coefficient of friction and this determines the friction force of a surface
Astronauts in a space station orbiting the earth still experience gravity however they will float around the station because they are in a continuous state of free fall and they will experience WEIGHTLESSNESS
Weight can be changed, mass CAN NOT
Everything with a mass exerts a gravitational force of attraction. The bigger the mass, the stronger the force