But why did they sink in the first place?

FORCES When you ride a bike, your foot PUSHES against the pedal. The push makes the wheels of the bike move. When you drop something, it is PULLED to the ground by gravity.

FORCES A FORCE is a PUSH or PULL in a particular DIRECTION. Sometimes, a force is also a twist!

FORCES FORCES AFFECT HOW OBJECTS MOVE. Forces can affect motion in the following ways: They can make objects: START MOVING MOVE FASTER MOVE SLOWER STOP MOVING CHANGE DIRECTION CHANGE SHAPE BIG SCIENCE IDEA

Forces cause ACCELERATION. Since forces cause changes in SPEED or DIRECTION of an object, we can say that…. Forces cause ACCELERATION.

There are lots of different types of forces: Thrust This can be any driving force, it may be a push or pull, but it could be an engine which forces an object forward. Lift This is the force required to raise an object through a fluid Air resistance This is a force which acts in the air, it can slow objects down when they are moving against it. Or if harnessed could be used to move an object along.

There are lots of different types of forces: Friction This force acts on objects when they are in contact with a surface, such as the ground. It can be reduced by ensuring both surfaces are smooth. Gravity This force affects every object on Earth. It is a force which pulls everything to the centre of the earth. Upthrust This is an upward force which acts in water, it acts on a object against gravity, and is why certain objects float. Other forces can’t be seen but form fields. Examples of this would be magnetic fields and electromagnetic fields.

Write the answer into a table in your book. Can you come up with an example of each one of these forces we have just defined? Write the answer into a table in your book.

Contact Forces Many forces which we observe are contact forces. These are forces such as friction or upthrust which act at a point of contact between two objects/materials. Eg. Friction on the tyres of a car acts at the point of contact between the tyres and the road. Upthrust on a boat acts at the point of contact between the water and the base of the boat.

Non-contact Forces Some forces which we observe are non-contact forces. These are forces such as gravity and magnetism which occurs without two objects/materials coming into contact. Non-contact forces can act over long distances. Eg. The Moon experiences a gravitational pull from Earth. Two magnets can push (repel) or pull (attract) each other without touching.

In Pairs: What forces are acting on this car which is driving along In Pairs: What forces are acting on this car which is driving along? (label the diagram with arrows showing the direction and type of force) For bonus points: Can you make the size of the arrows proportional to the force(s) acting on the car?

In Pairs: What forces are acting on this car which is driving along? This force is always present. It goes towards the centre of the earth, so will always be pointing from the top of the object This acts against the car, as it moves forward and is acting against the propulsion. Label these forces as contact or non-contact forces. Thrust This is the most powerful force, this should be your largest arrow, it should be pointing in the direction the car is going … This force is only present where the car is in contact with the floor, it acts against the propulsion.

In Pairs: What forces are acting on this car which is driving along? This force is always present. It goes towards the centre of the earth, so will always be pointing from the top of the object Non-contact This acts against the car, as it moves forward and is acting against the propulsion. Contact Contact Thrust This is the most powerful force, this should be your largest arrow, it should be pointing in the direction the car is going … Contact This force is only present where the car is in contact with the floor, it acts against the propulsion.

Experimental Work There are 5 stations around the room. You need to go to each station, complete the experiment, and complete the tasks into your book.

Let’s summarise! Forces are either a push or a pull in a certain direction but can also be a twist. Forces can make objects: START MOVING MOVE FASTER MOVE SLOWER STOP MOVING CHANGE DIRECTION CHANGE SHAPE Some examples of forces: Thrust Lift Air resistance Friction Gravity Upthrust Forces are either contact or non- contact forces. Contact forces act where two objects/materials meet. Non-contact forces act over a distance without the objects/materials touching each other.