MC Science_Activity Book with ans_Stage 6_C06

6 More About Forces Worksheet What Do You Know About Forces? Aim: To recall what you have learnt about forces Skills: Communicating, elaborating Recall what you have learnt about forces in the earlier stages Answer the questions in the table Question What is a force? A force is a push or a pull Give three examples of actions that are pushes A kick, a throw, a squeeze (Answer varies.) Give three examples of actions that are pulls A stretch, a tug, a lift towards the body (Answer varies.) What are the effects of forces? 80 Answer Forces can change the shape of things Forces can make a thing start or stop moving Forces can make a moving thing go faster or slower, or change direction What is friction? Friction is the force that opposes motion when two surfaces are in contact What are the effects of friction? It causes wear and tear It can slow down or stop a moving thing It produces heat Chapter Worksheet What Are Their Weights? Aim: To predict and find out the weight of various objects Skills: Observing, communicating, predicting, verifying, inferring What you need: Pear, string, forcemeter, different objects such as a book, pencil case, bag, shoe and brick Place a pear on your palm and feel its weight Use one end of a string to tie the pear Tie the other end of the string to the hook of a forcemeter to measure its weight forcemeter eye level Make sure the pointer is at eye level when you take a reading pear Record your reading in the table on the next page Get five other different objects Place each object in your palm to feel its weight Predict the weight of each object and write down your predictions in the table on the next page More About Forces 81 Repeat step using each of the five objects Record your readings below Are the actual weights of the objects close to your predictions? Weight of the object in N Object Prediction Actual pear (Answer varies.) Which object has the largest weight? (Answer varies.) Which object needs the largest force to be lifted? (Answer varies The object with the largest weight needs the largest force to be lifted.) 82 Chapter Worksheet Force Diagrams Aims: • To study force diagrams and decide whether the forces are balanced or unbalanced • To infer the effects of forces Skills: Observing, analysing, communicating, inferring Study these force diagrams A box at rest is pulled in opposing directions (a) Are the forces balanced? (b) What happens to the box? Yes The box does not move A box at rest is pulled in opposing directions (a) Are the forces balanced? (b) What happens to the box? No The box moves to the right More About Forces 83 A box is on the floor (a) Are the forces balanced? (b) What happens to the box? Yes The box does not move A box is in the air (a) Are the forces balanced? (b) What happens to the box? The box falls downwards 84 Chapter No Worksheet Which Tissue Paper Will Land First? Aim: To investigate which tissue paper will land on the ground first Skills: Observing, predicting, identifying variables, comparing, verifying, inferring, communicating What you need: Identical pieces of tissue paper, metre rule or measuring tape Carry out this activity indoors and ensure that there is no wind or breeze throughout the activity Work in groups of four Get three identical pieces of tissue paper Leave tissue paper as it is Fold tissue paper in half and crush tissue paper Tissue paper Tissue paper Tissue paper More About Forces 85 Three group members will each hold one of the pieces of tissue paper about 1.5 m from the ground Hold tissue papers and horizontally Make sure tissue paper is not folded in any way The last group member will count to three The other group members will let go of the tissue papers at the same time, from the same height Observe which tissue paper lands first, second and third on the ground Record your observations in the table below Repeat steps to and record your observations below Order in which the tissue paper lands Tissue paper First try Second try third third second second first first Write down three variables that are kept the same to ensure that the test is fair The type of tissue paper / The height from which the tissue papers are let go / The absence of wind or breeze / The timing to let go of the tissue papers (Any three) Which piece of tissue paper has the largest surface area? Tissue paper 10 Which piece of tissue paper has the smallest surface area? Tissue paper 86 Chapter 11 From your observations, does the tissue paper with the largest surface area land first or last? It lands last 12 Does the tissue paper with the smallest surface area land first or last? It lands first 13 Does the tissue paper with the largest or smallest surface area experience the greatest air resistance? The tissue paper with the largest surface area experiences the greatest air resistance 14 Predict which tissue paper will land first if the pieces of tissue paper are dropped at the same time and from the same height, in a place with no air Explain your answer All of them will land at the same time If there is no air, there will be no air resistance and the pieces of tissue paper will fall equally fast towards the ground More About Forces 87 Worksheet Do You Have Wrong Ideas About Forces? Aim: To correct wrong ideas or misconceptions about forces Skills: Analysing, communicating, elaborating These statements are false Correct each statement False statement 88 Corrected statement The weight of an object is measured in gram or kilogram The weight of an object is measured in newton Mass is measured in gram or kilogram Gravitational force acts on an object only when it is falling to the ground, not when it is on the ground Gravitational force acts on an object whether it is falling to or on the ground There are no forces acting on a box that is at rest on a table There are balanced forces acting on a box that is at rest on a table — the weight of the box and the upward force of the table on the box Work is done whenever a force acts on an object Work is done when a force that acts on an object makes the object move There is no frictional force when an object moves through air There is frictional force called air resistance when an object moves through air Chapter Let s Review Fill in the blanks Forces such as gravity acting on an object can be shown in acting on an object can such as force move frictional or diagrams gravitational the object force or friction force using when is acting on an object is is the force of the attraction an arrow to represent the weight between two objects energy is transferred direction of the object, measured in the unit and size newton the force that and as a result opposes motion when two surfaces are in contact for example of each force (N) which is different from work is done air resistance which is the mass of the object, measured in units such as gram (g) larger with a surface area moving through air, than one (kg) smaller with a surface area or kilogram greater for an object More About Forces 89 Reflection Tick (✔) to show how well you have learnt Revise the Pupil s Book section(s) that you not know well I have learnt to Yes Not sure No Pupil s Book section(s) distinguish between mass measured in kilogram (kg) and weight measured in newton (N), noting that kilogram is used in everyday life A recognise and use units of force, mass and weight, and identify the direction in which forces act A, B recognise the concept of energy in movement B recognise friction, including air resistance, as a force which can affect the speed of a moving object and sometimes stop a moving object C Suggestion(s) to Guide Pupils Worksheet 4, : Provide pupils with choices for the variables Worksheet 5: Provide pupils with the answer but replace some words with blanks Let pupils fill in the blanks Let’s Review: Provide pupils with helping words 90 Chapter ... Provide pupils with choices for the variables Worksheet 5: Provide pupils with the answer but replace some words with blanks Let pupils fill in the blanks Let’s Review: Provide pupils with helping... paper with the largest surface area land first or last? It lands last 12 Does the tissue paper with the smallest surface area land first or last? It lands first 13 Does the tissue paper with the... (✔) to show how well you have learnt Revise the Pupil s Book section(s) that you not know well I have learnt to Yes Not sure No Pupil s Book section(s) distinguish between mass measured in kilogram