Forces+-+Science

FORCES Emily Bryan-Kinns, Vanessa Pedley, Suzanne Gilmour and Richard Todd

(BBC Bitesize & Gannon, 2008)
 * Forces are nearly always pushes or pulls.
 * They are measured in Newtons (N) using a Newton or force meter.
 * Forces cannot be seen but the result of the force can be seen.
 * Forces usually act in pairs and always in a certain direction.
 * The mass of an object is how much matter it contains and it is measured in grams (g) or kilograms (kg). Mass is not a force.
 * The weight of an object is the force caused by gravity pulling down on the mass and it is measured in Newtons (N).

//Gravity// (BBC Bitesize & Gannon, 2008)
 * The force that makes things fall to the ground on Earth is called gravity.
 * Gravity holds Earth and the other planets in their orbits around the Sun.
 * Gravity exists on the Moon but it is not as strong as it is on the Earth, this is because the Moon is much smaller than the Earth.

//Balanced Forces// (BBC Bitesize & Gannon, 2008)
 * Forces are shown by arrows in diagrams. The direction of the arrow shows the direction in which the force is acting. The bigger the arrow, the bigger the force.
 * If two forces are balanced, it means the forces are the same size but are acting in opposite directions.
 * Balanced forces produce no change in movement.
 * If two balanced forces are acting on an object, that object will not change its motion.
 * If it is still, it will stay still.
 * If it is moving, it will continue moving, in the same direction and at the same speed.

//Unbalanced Forces// (BBC Bitesize & Gannon, 2008)
 * Unbalanced forces change the speed and/or direction of moving objects.
 * Unbalanced forces can make objects start to move, speed up, slow down, turn, change shape or change direction.

//Gravity, Air Resistance and Friction// There are a number of forces which act on any object travelling in a straight line at a constant speed on or near the surface of the earth and they include: If a cyclist pedalling in a straight line along a horizontal road then stopped pedalling and began to freewheel, the combined effects of gravity, friction and air resistance would eventually cause the cycle to slow down and stop. (Farrow, 1999)
 * The ‘pull’ of the earth’s gravity
 * The force which tends to resist movement between objects – friction
 * Air resistance – a form of friction.



__Friction __ Activity - Science Experiment looking at how friction works

**KS1 - Sc4 Physical Processes** //**Forces and Motion**// 2. Pupils should be taught: (National Curriculum)
 * 1) to find out about, and describe the movement of, familiar things [for example, cars going faster, slowing down, changing direction].
 * 2) that both pushes and pulls are examples of forces.
 * 3) to recognise that when things speed up, slow down or change direction, there is a cause [for example, a push or a pull].

**KS2 - Sc4 Physical Processes** **//Forces and Motion//** 2. Pupils should be taught: (National Curriculum)
 * 1) about the forces of attraction and repulsion between magnets, and about the forces of attraction between magnets and magnetic materials.
 * 2) that objects are pulled downwards because of the gravitational attraction between them and the Earth.
 * 3) about friction, including air resistance, as a force that slows moving objects and may prevent objects from starting to move.
 * 4) that when objects [for example, a spring, a table] are pushed or pulled, an opposing pull or push can be felt.
 * 5) how to measure forces and identify the direction in which they act.

__** Silly Symphony – The Three Little Pigs **__ media type="youtube" key="Olo923T2HQ4" height="360" width="480"

It is a useful video for a quick introduction/starter/elicitation session for the topic of forces. It is fun and interactive, telling a story that children should be familiar with. The video can be stopped at different points for discussion or to ask what the children will think will happen next. The video gets the children talking about forces without even realising it!

Watch the video, working through these points for discussion, stopping the video if necessary:
 * When the wolf is blowing the house made out of hay, the pig is trying to hold the door in place using furniture etc. Does this work? How come the door still blows away? (It is because the force of the blow is greater than the force of the pig pushing/the objects etc. Don’t expect this answer from children, this is just for the teacher to know.) Why doesn’t the pole move?
 * What happens when the wolf blows the house made out of sticks? How come the door doesn’t fall down this time? (There are two pigs pushing on the other side)
 * How come the wolf can’t stop the pigs from running away when he is grabbing hold of their tales? (The force of the wolf pulling on them is less than that of them pulling away. Again, don't expect this answer from the children.) How come the wolf gets pulled along?
 * What stops the wolf being pulled along? (The tree – an obstacle)
 * What happens to the apples? How come the apples fall to the ground?
 * How did the last pig lock the door? (__Pushing__ the bolt)
 * How does the pig play the piano? What does he do to the keys?
 * How does the pig open/close the door?
 * What does the pig do with the brush? (Hit the wolf over the head – pushing)
 * What does the pig do with the rug? (Pulls it) And what happens to the wolf? (He falls over)
 * Why doesn’t the brick house fall down?
 * What does the wolf do to try and open the door?
 * What happens when the wolf goes into the chimney? (He __falls__ in)
 * What happens when the water starts to boil? (He jumps up the chimney and __falls__ to the ground)

Possible follow-up investigation: An investigation could be developed around building different 'houses' and testing their stability using fans. Vary size of house, material and strength of fan for different investigations.

__The Paper Helicopter Investgation__ What makes the best paper helicopter? A simple question such as this can lead onto a fun and engaging science investigation for KS2 pupils. There are many different variables that can be tested and alternative ways of testing them, meaning that there is the option of dividing the pupils into groups and having each group test a different variable, if the class are working at a high enough level. Possible questions to spark discussion regarding the different variables include: How you measure the speed is up to you, it could be done using a timer (although remember that paper helicopters fall very quickly!), or by counting the number of spins the propellers complete before hitting the ground. Obviously the longer the helicopter takes to hit the ground the better. By the end, the class should know the requirements for the best paper helicopter!
 * How does the parachute's material effect how fast it falls?
 * How does the length of its wings affect how fast it falls?
 * What happens if we change the length of the base?
 * What about the helicopter's weight? Does this affect the speed of its fall? (Weight can be changed by adding paper-clips to the wings)

__ Forces: __ __ Glossary of Useful Vocabulary __
 * Air Resistance ** The force caused by air pushing against a moving object.
 * Arrow ** Arrows show the direction and size of a force (big force/large arrow, small force/small arrow, left or right).
 * Balanced Forces ** Two equal forces in opposite directions cancelling each other out. No change in the movement or shape.
 * Drag ** The resistance to the motion of a body passing through air or fluid.
 * Force ** A force is either a push or pull.
 * Force meter ** Also known as a ** newton meter **. Spring balance used to measure force. Three different types are available: pull, push and push/pull.
 * Friction ** The force between two surfaces, when one surface moves over the other –gives us grip
 * Gravity ** The force that pulls us to the centre of the earth.
 * Magnetism ** Magnets generate a magnetic field around them. They always have a North and South Pole. When they repel they push each other away, when they attract they pull together. Opposite poles attract, like poles repel.
 * Newton ** Unit we measure force in.
 * Streamlined ** To travel faster through air, things are designed to be streamlined (aerodynamic) to reduce air or water resistance.
 * Unbalanced Forces ** One force is bigger than the other. This then changes the speed and or direction of moving objects.
 * Upthrust ** The force that pushes objects upwards when they are placed in liquids.
 * Water Resistance ** The force of water pushing back on an object moving through it.
 * Weight ** The force that is felt when gravity pulls an object down.

**References:** @http://www.bbc.co.uk/schools/ks2bitesize/science/physical_processes/forces/read1.shtml @http://curriculum.qcda.gov.uk/key-stages-1-and-2/subjects/science/keystage1/index.aspx @http://curriculum.qcda.gov.uk/key-stages-1-and-2/subjects/science/keystage2/index.aspx Gannon, P. 2008, //CGP Key Stage Three Science - The Revision Guide, Levels 3-6//, Coordination Group Publications Ltd. Farrow, S. 1999, The Really Useful Science Book - A Framework of Knowledge for Primary Teachers, TJ International Ltd CGP Publications, Key Stage Two Science the Study Book Cross, A and Bowden A (2009) Essential Primary Science, Buckingham: Open University Press CGP Publications, GCSE Core Science The Usborne Pocket Scientist, The Blue Book (includes internet links and useful experiments for children [|www.usborne-quicklinks.com] ).

**Useful Websites:** @http://www.bbc.co.uk/schools/scienceclips/ages/6_7/forces_movement.shtml @http://www.bbc.co.uk/schools/ks2bitesize/science/physical_processes/forces/play.shtml @http://www.engineeringinteract.org/resources/parkworldplot/flash/concepts/allaboutforces.htm @http://primaryhomeworkhelp.co.uk/revision/Science/physical.htm [] [] [] [] []