Mass & Weight D. Crowley, 2008

Mass & Weight To know the difference between mass and weight Saturday, April 15, 2017 Mass & Weight To know the difference between mass and weight

Space Neil Armstrong was the first man to walk on the moon When he walked on the moon was his weight the same or different to his weight on Earth?

Space Neil Armstrong had a weight of 800N on Earth But when he walked on the moon his weight was much less, around 128N So he weighed less on the moon - but this does not mean there was any less of him (he still had two arms, two legs etc…)! Its all because of gravity…

Gravity All objects have a force that attracts them towards each other - this is gravity Even you attract other objects to you because of gravity, but you have too little mass for the force to be very strong (gravity only becomes noticeable when there is a really massive object like a moon, planet or star) When you jump, the gravitational force of the Earth pulls you down, but your gravitational force also pulls the Earth towards you! You just don’t notice this effect because your mass is so much smaller than Earth’s

The moon has a gravity of just 1.6N/kg (as it is much smaller) Earth’s gravity pulls objects towards its centre - it has a force of 10N/kg The moon has a gravity of just 1.6N/kg (as it is much smaller)

Mass What is mass? The mass of an object is the amount of matter or "stuff" it contains. The more matter an object contains, the greater its mass An elephant contains more matter than a mouse, so it has a greater mass Mass is measured in kilograms (kg) An object's mass stays the same wherever it is in the universe (if you have two arms and legs on Earth, then these will be present on the moon, on Saturn, in deep space, in a black hole etc…)

weight (N) = mass (kg) x gravitational pull (N/kg) Weight is a force caused by the pull of gravity acting on a mass weight (N) = mass (kg) x gravitational pull (N/kg) An elephant has more mass than a mouse, so it has a greater weight (if the mouse and elephant are influenced by the same gravity) Weight is measured in newtons (N) and has both magnitude and direction Weight has different values depending on where you are in the Universe. An object's weight can change if it goes into space or to another planet, because gravity may be weaker or stronger

weight (N) = mass (kg) x gravity (N/kg) Earth Gravity on Earth = 10N/kg Say you have a mass of 100kg on Earth Can you work out your weight? Remember: - weight (N) = mass (kg) x gravity (N/kg) Your weight on Earth is 100kg x 10N Your weight = 1000N

Moon Say you have a mass of 100kg on Earth Gravity on moon = 1.6N/kg Say you have a mass of 100kg on Earth What is your mass on the moon? Remember, mass is the amount of stuff there is (you still have two arms, two legs etc… on the moon) Mass = 100kg on moon What is your weight on the moon (weight = mass x gravity)? Your weight on the moon is 100kg x 1.6N Your weight = 160N

Your mass & weight See if you can work out your mass and weight on the Earth and on the moon Remember: Gravity on Earth = 10N/kg Gravity on the moon = 1.6N/kg

Gravity Complete the gravity on other planets worksheet

Gravity Although your mass is always the same wherever you are, you would weigh the most on Jupiter, and the least on Pluto

Weight Bingo

Questions On Mercury (3) the mass of 10kg = On Venus (9) the mass of 5kg = On Earth (10) the mass of 5kg = On Mars (4) the mass of 4kg = On Jupiter (23) the mass of 2kg = On Saturn (9) the mass of 9kg = On Uranus (8) the mass of 10kg = On Neptune (11) the mass of 50kg = On Pluto (0.4) the mass of 90kg = 1On Mercury (3) the mass of 30kg = On Venus (9) the mass of 15kg = 1On Earth (10) the mass of 25kg = On Mars (4) the mass of 100kg = On Jupiter (23) the mass of 10kg = On Saturn (9) the mass of 20kg = 30 45 50 16 46 81 80 550 36 90 135 250 400 230 180

Questions On Uranus (8) the mass of 16kg = On Neptune (11) the mass of 11kg = On Pluto (0.4) the mass of 50kg = On Mercury (3) the mass of 70kg = On Venus (9) the mass of 45kg = On Earth (10) the mass of 12kg = On Mars (4) the mass of 60kg = On Jupiter (23) the mass of 5kg = On Saturn (9) the mass of 52kg = On Uranus (8) the mass of 95kg = On Neptune (11) the mass of 54kg = On Pluto (0.4) the mass of 80kg = On Mars (4) the mass of 21kg = On Jupiter (23) the mass of 29kg = On Venus (9) the mass of 65kg = 128 121 20 210 405 120 240 115 468 760 594 32 84 667