CAMBRIDGE LOWER SECONDARY SCIENCE 9 UNIT 3: FORCES AND ENERGY Name ___________________________________ Date _____________ Worksheet 3.1A Density In this activity, you will calculate density and decide whether objects will float or sink in water. In these questions, use the equation density = 1 mass volume Calculate the density of: a substance A, with a mass of 120 g and a volume of 100 cm3 ______________________________ g/cm3 b substance B, with a mass of 1.3 g and a volume of 1000 cm3 ______________________________ g/cm3 c substance C, with a mass of 97 g and a volume of 10 cm3 ______________________________ g/cm3 d One of the substances, A, B or C is a gas. Which one is a gas? Write the letter _______________ Cambridge Lower Secondary Science 9 – Mary Jones, Diane Fellowes-Freeman and Michael Smyth © Cambridge University Press 2021 1 CAMBRIDGE LOWER SECONDARY SCIENCE 9 UNIT 3: FORCES AND ENERGY 2 a Calculate the density of polystyrene that has a mass of 50 g and a volume of 1000 cm3. ______________________________ g/cm3 b Calculate the density of rubber that has a mass of 1500 g and a volume of 1000 cm3. ______________________________ g/cm3 c Floats are used in swimming pools to help people to learn to swim. The density of water in swimming pools is 1.0 g/cm3. i Which substance, polystyrene or rubber, is more suitable for making floats? ____________________________________________________________________________ ii Explain your choice. ____________________________________________________________________________ ____________________________________________________________________________ Cambridge Lower Secondary Science 9 – Mary Jones, Diane Fellowes-Freeman and Michael Smyth © Cambridge University Press 2021 2 CAMBRIDGE LOWER SECONDARY SCIENCE 9 UNIT 3: FORCES AND ENERGY Name ___________________________________ Date _____________ Worksheet 3.1B Density In this activity, you will calculate density and decide whether objects will float or sink in water. 1 Calculate the density of: a substance A, with a mass of 120 g and a volume of 100 cm3 ______________________________ g/cm3 b substance B, with a mass of 1.3 g and a volume of 1000 cm3 ______________________________ g/cm3 c substance C, with a mass of 97 g and a volume of 10 cm3 ______________________________ g/cm3 d One of the substances, A, B or C is a gas. Which one is a gas? Write the letter _______________ e One of the substances, A, B or C is a metal used for building bridges. Which one is a metal? Write the letter _______________ Cambridge Lower Secondary Science 9 – Mary Jones, Diane Fellowes-Freeman and Michael Smyth © Cambridge University Press 2021 3 CAMBRIDGE LOWER SECONDARY SCIENCE 9 UNIT 3: FORCES AND ENERGY 2 a Calculate the density of polystyrene that has a mass of 50 g and a volume of 1000 cm3. ______________________________ g/cm3 b Calculate the density of polyethylene that has a mass of 850 g and a volume of 1000 cm3. ______________________________ g/cm3 c Floats are used in swimming pools to help people to learn to swim. The density of water in swimming pools is 1.0 g/cm3. Explain whether polystyrene or polyethylene is better for making floats. _______________________________________________________________________________ _______________________________________________________________________________ Cambridge Lower Secondary Science 9 – Mary Jones, Diane Fellowes-Freeman and Michael Smyth © Cambridge University Press 2021 4 CAMBRIDGE LOWER SECONDARY SCIENCE 9 UNIT 3: FORCES AND ENERGY 3 A submarine is a type of ship that travels underwater. Submarines can change their density to float or sink. The diagram shows a section through the inside of a submarine. The submarine changes density by changing the volume of air and the volume of water in the ballast tank. Complete the table using the words increase or decrease to show how these volumes change for floating and sinking. Submarine action Change in volume of air Change in volume of water Floating Sinking Cambridge Lower Secondary Science 9 – Mary Jones, Diane Fellowes-Freeman and Michael Smyth © Cambridge University Press 2021 5 CAMBRIDGE LOWER SECONDARY SCIENCE 9 UNIT 3: FORCES AND ENERGY Name ___________________________________ Date _____________ Worksheet 3.1C Density In this activity, you will calculate density and decide whether objects will float or sink in water. 1 Calculate the density of: a substance A, with a mass of 120 g and a volume of 100 cm3 ______________________________ g/cm3 b substance B, with a mass of 1.3 g and a volume of 1000 cm3 ______________________________ g/cm3 c substance C, with a mass of 97 g and a volume of 10 cm3 ______________________________ g/cm3 Cambridge Lower Secondary Science 9 – Mary Jones, Diane Fellowes-Freeman and Michael Smyth © Cambridge University Press 2021 6 CAMBRIDGE LOWER SECONDARY SCIENCE 9 UNIT 3: FORCES AND ENERGY d Write the letters A, B and C in the table to show what these substances are. Name of substance Letter air rubber steel 2 a Calculate the density of polypropylene that has a mass of 910 g and a volume of 1000 cm3. ______________________________ g/cm3 b Calculate the density of polymethylacrylate that has a mass of 1100 g and a volume of 1000 cm3. ______________________________ g/cm3 c Ropes are used in swimming pools to mark lanes for swimmers. The ropes are designed to float. The density of water in swimming pools is 1.0 g/cm3. Explain which of polypropylene or polymethylacrylate is better for making ropes for swimming pools. _______________________________________________________________________________ _______________________________________________________________________________ Cambridge Lower Secondary Science 9 – Mary Jones, Diane Fellowes-Freeman and Michael Smyth © Cambridge University Press 2021 7 CAMBRIDGE LOWER SECONDARY SCIENCE 9 UNIT 3: FORCES AND ENERGY 3 A submarine is a type of ship that travels underwater. Submarines can change their density to float or sink. The diagram shows a section through the inside of a submarine. The submarine changes density by changing the volume of air and the volume of water in the ballast tank. Explain how the volumes of air and water in the ballast tank should change for the submarine to: a float _______________________________________________________________________________ _______________________________________________________________________________ _______________________________________________________________________________ b sink. _______________________________________________________________________________ _______________________________________________________________________________ _______________________________________________________________________________ Cambridge Lower Secondary Science 9 – Mary Jones, Diane Fellowes-Freeman and Michael Smyth © Cambridge University Press 2021 8 CAMBRIDGE LOWER SECONDARY SCIENCE 9 UNIT 3: FORCES AND ENERGY Name ___________________________________ Date _____________ Worksheet 3.2 Heat and temperature In this activity, you will compare heat and temperature. 1 Each of the statements below refers to either heat or temperature. Draw straight lines to match each statement to either heat or temperature. Statement 12 500 J is needed to make the water boil. The boiling point of ethanol is 78 °C. heat At the coldest place on Earth, −71 °C was recorded. temperature Thermal energy must be removed from water to make water freeze. Cambridge Lower Secondary Science 9 – Mary Jones, Diane Fellowes-Freeman and Michael Smyth © Cambridge University Press 2021 9 CAMBRIDGE LOWER SECONDARY SCIENCE 9 UNIT 3: FORCES AND ENERGY 2 Compare the heat and temperature of each of these. a 250 g of water at 10 °C and 250 g of water at 20 °C. Heat __________________________________________________________________________ _______________________________________________________________________________ Temperature ___________________________________________________________________ _______________________________________________________________________________ b 10 g of iron at 50 °C and 100 g of iron at 500 °C. Heat __________________________________________________________________________ _______________________________________________________________________________ Temperature ___________________________________________________________________ _______________________________________________________________________________ 3 Describe what happens to the heat and temperature of each of these. a 5 g of liquid water at 10 °C being cooled to 5 °C with no change in mass. Heat __________________________________________________________________________ _______________________________________________________________________________ Temperature ___________________________________________________________________ _______________________________________________________________________________ b 320 g of liquid propanol at 50 °C decreasing in mass to 200 g at 50 °C. Heat __________________________________________________________________________ _______________________________________________________________________________ Temperature ___________________________________________________________________ _______________________________________________________________________________ Cambridge Lower Secondary Science 9 – Mary Jones, Diane Fellowes-Freeman and Michael Smyth © Cambridge University Press 2021 10 CAMBRIDGE LOWER SECONDARY SCIENCE 9 UNIT 3: FORCES AND ENERGY Support sheet 1 Start by recalling the unit of temperature and the unit of heat. Use the units in the statements to match to either heat or temperature. The last statement contains the word energy. Think whether temperature or heat is a measure of energy when matching this statement. 2 Remember that the heat in an object is a measure of the total energy of all the particles. Think: • what happens to the energy of particles as the temperature increases • what happens to the number of particles as the mass of a substance increases 3 This question uses the same ideas as question 2. The only difference is that the same substance is changing. Cambridge Lower Secondary Science 9 – Mary Jones, Diane Fellowes-Freeman and Michael Smyth © Cambridge University Press 2021 11 CAMBRIDGE LOWER SECONDARY SCIENCE 9 UNIT 3: FORCES AND ENERGY Name ___________________________________ Date _____________ Extension sheet 2 Answer question 2 and explain the similarities and differences in terms of particles. __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ 3 Just as in question 2, include particles in your explanations for the answer to question 3. __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ 4 Compare, using ideas about particles, the heat changes in • 100 g of liquid water at 10 °C cooling to 0 °C with no change in mass and no change of state • 100 g of liquid water at 10 °C cooling to 0 °C and freezing to form ice at 0 °C with no change in mass. __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ Cambridge Lower Secondary Science 9 – Mary Jones, Diane Fellowes-Freeman and Michael Smyth © Cambridge University Press 2021 12 CAMBRIDGE LOWER SECONDARY SCIENCE 9 UNIT 3: FORCES AND ENERGY Name ___________________________________ Date _____________ Worksheet 3.3 Conservation of energy In this activity, you will think about how the law of conservation of energy applies to different situations. 1 State the law of conservation of energy. __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ 2 Explain how the law of conservation of energy applies to: a an electric lamp that changes electrical energy to light energy and thermal energy _______________________________________________________________________________ _______________________________________________________________________________ _______________________________________________________________________________ b a truck engine that changes chemical energy to kinetic energy, sound energy and thermal energy _______________________________________________________________________________ _______________________________________________________________________________ _______________________________________________________________________________ Cambridge Lower Secondary Science 9 – Mary Jones, Diane Fellowes-Freeman and Michael Smyth © Cambridge University Press 2021 13 CAMBRIDGE LOWER SECONDARY SCIENCE 9 UNIT 3: FORCES AND ENERGY c a television _______________________________________________________________________________ _______________________________________________________________________________ _______________________________________________________________________________ d an active adult who is not gaining or losing body mass. _______________________________________________________________________________ _______________________________________________________________________________ _______________________________________________________________________________ Cambridge Lower Secondary Science 9 – Mary Jones, Diane Fellowes-Freeman and Michael Smyth © Cambridge University Press 2021 14 CAMBRIDGE LOWER SECONDARY SCIENCE 9 UNIT 3: FORCES AND ENERGY Worksheet 3.3 Teacher support sheet These questions are designed to differentiate by outcome. 1 Most learners should have the idea that (the quantity of) energy stays the same. Others will have the idea that energy cannot be created / made or destroyed, although they can express this in different ways. Some may continue the law to state that energy can be changed or transferred. A specific example is not acceptable, as the law should be expressed in a general form. 2 For each of these, learners should have the idea that ‘energy in equals energy out’. Others may further qualify this as the total energy input to the system is equal to the total of the energy types output. In each case, reference should be made to the energy types specific to that example. Parts c and d are, therefore, more challenging as the energy types are not given. Cambridge Lower Secondary Science 9 – Mary Jones, Diane Fellowes-Freeman and Michael Smyth © Cambridge University Press 2021 15
