1 Ambition – Respect - Excellence Ardrossan Academy Dead Earth Subtopic – SPACE – Gravity, MASS & weight

2 Ambition – Respect - Excellence Lesson Title: Gravity, Mass & Weight Learning Intention:. To understand how the strength of gravity affects the weight of objects on different planets Activity:Gravity Research & graphing I will be successful if I can : Use data from the internet to calculate the weight of objects on different places in the Solar System

MASS All objects are made up from tiny particles called ATOMS – these give them MASS Mass is a measure of how much matter there is in an object - it is measured in kilograms (kg) A set of scales will give you your mass in kilograms

GRAVITY Gravity produces a force which acts between all objects in the universe Any two objects with mass will have a force that attracts them to each other The strength of these gravitational forces depends on the size of the masses involved

WEIGHT Weight is the name of the FORCE caused by the pull of gravity acting on a mass Like other forces, weight is measured in newtons (N) On Earth, an apple with a mass of 0.1 kg, will have a weight of about 1 N. (lots of people mistake weight for mass – be careful!)

GRAVITY, STARS & PLANETS Stars and planets are very large objects, which have a huge amount of mass. The Earth has a mass of 6 x kg (that’s a 6 followed by 24 zeroes) The Sun’s mass is almost a million times greater (six more zeroes on the end!) Because their masses are very large they have strong gravitational forces

GRAVITY, STARS & PLANETS The Sun’s gravity is so strong it keeps the other planets in orbit around it Each planet’s gravity is different due to their different masses The Earth’s gravity is stronger than Mars, but weaker than Jupiter

GRAVITY, MASS AND WEIGHT The gravitational force acting on objects on Earth makes them feel heavy. This is what we call WEIGHT The greater the mass of an object, the greater its weight will be

GRAVITY, MASS AND WEIGHT Weight is related to mass by the strength of gravity This can be written as a formula – weight = mass x gravity On Earth, the strength of gravity is 10 newtons for each kilogram (10 N/kg)

ACTIVITY 1 – GRAVITY ON PLANETS PLANETGRAVITY STRENGTH (N/kg) Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune Copy the table into your jotter, leaving room for another column Using any relevant source (website, textbook etc) find the strength of gravity on each planet (on some web sites it might be given in other units – m/s 2 )

ACTIVITY 2 – BUZZ’S WEIGHT ON PLANETS PLANETGRAVITY STRENGTH (N/kg) Buzz’s Weight (N) Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune Add another column to your table headed ‘Buzz’s Weight (N)’ Use the formula – weight = mass x gravity to calculate the weight of a 0.5 kg Buzz Lightyear on each planet Use your values to draw a bar graph showing Buzz’s weight on different planets