FACTFILE

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Pupil Resource Sheet




                           Measuring Forces


                       FACTFILE
                       n    The easiest way to measure force is with a Newton metre or spring
                            balance.

                       n    Speed is measured by taking the time and dividing it into the distance
                            travelled.

                       n    Air pressure is measured using either an aneroid or a mercury
                            barometer.

                       n    In a mercury barometer the pressure of the air is registered on the
                            mercury which moves up a scale.

                       n    In an aneroid barometer the pressure pushes onto a thin box of air
                            and this moves a lever.




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Pupil Resource Sheet




                           Measuring Forces


                       You are going to try to find the
                       answers to these questions

                       n    How can you measure forces?

                       n    How can you measure the force of gravity?




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Pupil Resource Sheet




                           Measuring Forces


                       NOW TRY THIS
                       You will need:
                       n    A stop clock
                       n    A toy car
                       n    A slope that can be made of a
                            piece of wood
                       n    A set of bathroom scales
                       n    A tin can with three holes in
                            one side one above the other
                       n    A barometer
                       n    A spring and 4 weights of
                            known weight
                       n    A metre rule



                       Experiment 1 - Measuring the effects of force by
                       measuring distance and speed of an object
                       n    Use the toy car a stopwatch and a slope.
                       n    Try to think of a way of always using the same force to push the car
                            along.
                       n    Use your slope /plank of wood and lay it flat
                       n    Push the car along on the flat surface and measure the distance it
                            travelled and the length of time it took
                       n    The speed is calculated by dividing the distance the car travelled by
                            the time it took.
                       n    Write out the sum and your working out
                       n    What was the speed of the car?
                       n    Continue this experiment by making a gradual slope and a steep slope
                            and repeat the measurements and record them
                       n    Record this on the chart on the next page




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                           Measuring Forces


                       RECORD YOUR RESULTS
                       Situation            Distance           Time               Speed


                       Car on flat


                       Car on slope 1


                       Car on slope 2


                       Car on different
                       surface


                       n    What was the effect on the car of the different situations?




                       n    Did friction play a part? How?




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                           Measuring Forces

                       Experiment 2 - Force

                       You will need a set of bathroom scales.

                       n    Hold the scales close to your chest with the scale showing on the
                            outside

                       n    Ask your partner to read the scale while you pull the surface of the
                            scale towards your chest with flat hands

                       n    What is the measure of the force of pressure that you are applying?




                       n    Try again.

                       n    Your partner should also do this record your results.




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                           Measuring Forces

                       Experiment 3 - Pressure in liquids

                       n    Fill the tin can to the top with water.

                            Do this over the sink .

                            Watch the flow of water and the angle of
                            the flow and draw the results.

                        What force was working here?




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Pupil Resource Sheet




                           Measuring Forces

                       Experiment 4 - Measuring the effects of the force of weight

                       You will need a spring and a set of weights and a ruler

                       n    Draw a bar graph of your results with the weight on the y axis and the
                            length that the spring stretched on the x axis

                       n    Measure the length of the spring without the weights and record it on
                            your bar chart

                       n    Place a weight on the end of the spring it is best to start with the
                            lightest weights first

                       n    Measure the length of he spring and record

                       n    Repeat the experiment with all the weights and draw your bar chart.

                       n    What can you now say about the spring and the weights?

                       n    Write this as a conclusion




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Pupil Resource Sheet




                        Measuring Forces


                       NOW TRY THIS
                       Look at the barometer with the teacher.

                        n How does it work?




                        n What does it measure?




                        n Why is this useful information?