4-FAD-01

Outcomes

• Pupils can arrange all the GCSE quantities into two groups: scalars and vectors.
• Pupils appreciate that force is a vector quantity and understand the nature of this.
• Pupils can name and label forces on stationary objects using arrows (1-D) and show that they are balanced.
• Pupils can add force vectors that act along a line.

Specification References

• 1.10 distinguish between vector and scalar quantities
• 1.11 appreciate the vector nature of a force
• 1.12 add forces that act along a line

Starter

• Students are split into groups of six and are given packs of cards with all the GCSE quantities written on them. They are asked to put them into two groups: 1) those that have a direction and can be represented with an arrow (a vector) and 2) those that do not (a scalar).
• These cards should be left in these groups while they carry out work on the force table.
• The groups of six can be split into groups of two to investigate vectors on the force tables. They can work through this force table work sheet where they are asked to apply different arrangements of masses/forces pulling on a central block. They are asked to make and record a prediction before releasing the block and also to record their observations.
• Regroup them and ask them to discuss the observations and write their own definition for a vector and scalar quantity on the mini whiteboards.
• Discuss the groups outcomes and write a defintion to be recorded in their books. Emphasise that vector quantities could be negative whereas scalar quantities cannot. (They may argue about temperature where they can be introduced to the Kelvin scale)
• Have the groups reassess their vector and scalar groups from the beginning of the exercise and make any corrections they feel they need to make.
• Make a centralised list on the board and have them copy this under their defintions in their books.

Main Body of Lesson

• Use the Force vectors powerpoint. Discuss the images and have the class help label the forces using arrows. Guide them towards the correct direction of arrow and type of force as revision from the 3rd year. Begin looking for pairs of forces which are balanced and result in zero force on the object.
• Explain that force vectors are depicted as arrows to show the direction, with the length of the arrow representing the magnitude of the force. You could introduce the 'head' and 'tail' of the force vector.
• Use the last few images (the canal boat and the loop) in the powerpoint to introduce the idea that the resultant of two given forces is an imaginary force and is equivalent to the actual forces. It would have the same effect as the real forces combined.
• Go through the examples on how to add vectors from the power point slide. Emphasis how to add vectors 'head to tail'. Make them redraw the arrows in 'head to tail' formation.
• If there is time and you wish to extend to 2-D vectors a nice activity is to use the trio of ropes tied to a loop. In groups of four, have three pupils pull on the three ropes using forcemeters. They should pull and create a 'balanced loop' which is resting on the A3 paper. The fourth member uses a ruler to trace the three ropes with a pencil (on both sides) and label the force from the forcemeter. The centre of the loop should also be marked. Now have them take the loop and rope away and using the pencil draw the force vectors leading from the centre of the loop. The vectors should be in the correct direction and be drawn to scale. (i.e 2cm = 1N) Now using the acetate sheet they should trace the vectors one at a time 'adding them' head to tail. (They will get the direction correct if they concentrate on keeping the acetate edge parallel with the paper edge. The three force vectors should create a triangle showing that they are balanced or the resultant is zero.

Plenary

• Use this Adding Forces sheet. Student should add forces along a line and may go onto an extension activity where they both label and add up forces for a number of situations.

Homework

• Students could research the difference between distance and displacement, speed and velocity and how the change in velocity can occur by the velocity only changing direction and not magnitude. This could lead to acceleration and circular motion.

Additional Information

Resources Required

• Class set of quantity cards in envelopes + whiteboards
• Force tables - boards x 12, bull dog clips with one lever bent upward x 48, string, block with four eyelets at the centre of each side, 100g mass sets, deep plastic trays x 24
• Set of 'ring with three ropes' systems, 3 Newton meters x 3, A3 sheet x 1, acetate sheet x 1 , rulers x 1 and OHP pen x 1.

Textbook References

• None

Website References

• None

Safety/Hazards

• None

Notes

• None