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Grade 7Measurement and DensityCurriculum standards: 17.1, 17.2Objectives1-Know how to measure length and calculate area of regular objects. ????? ???? ????? ????? ??????? ??????? ????????2-Express large and small units using appropriate prefixes.??????? ?? ??????? ??????? ???????? ???????? ??????? ????????.KEY WORDS??????Meter?????Unit????Area?????3818890350520Measuring is an important part of science. The metric system is an important part of science.SI unit: Means system international. It is the modern form of the metric system. It is based on the units of ten.?????? ??????? ?? ??? ???? ?????? ?????? ??????? ????? ?? ??????? 10.Prefixes are used to change the size of a unit. ??????? ?????? ?????? ??? ??????.518096526670402844026670297180026670The three basic quantities we have to measure in physics are length, mass, and time. How do you measure length?Length is measured in a unit called the Metre (M).????? ?? ???? ???? ????? ????????Rulers are used for measuring length. The ruler shows only centimeters & millimeters not metersRuler 1285240216535570928514605043897553079753176905307975Trundle wheelMeasuring tape3465830995045Metre rulerTo measure large lengths you can use a metre ruler or a measuring tape or trundle wheel.To measure small lengths you can use micrometer.MicrometreHow do you calculate Area?Area of a rectangle= length x WidthArea is measured in square units, such as square meters (m2).????? ????????= ????? X ???????????? ???? ???????? ??????? ??? ????? ??????356679596520Calculate the area of the following rectangle. ???? ????? ???????? ?????? …………………………………………………………………………………………………………………………………………………….WorksheetQ1: Here is a list of instruments used for measuring length: ???? ?????? ?? ??????? ????? ?????Meter ruler calibrated in millimeter divisions.30 cm ruler calibrated in 0.5mm division.50 m tape measure.Micrometer screw gauge.Trundle wheel.Trundle wheelMicrometerWhich would you use to measure the following distances??? ??????? ??? ?????? ????? ???????? ???????? The distance traveled by a snail in 5 minutes???????? ???? ?????? ??????? ?? ??? ?????………………………………………………………… The diameter of a wire? ??? ???………………………………………………………… The circumference of the school ground? ???? ???? ??????? …………………………………………………………Your height ????…………………………………………………………… The width of a paper. ??? ???? …………………………………………………………How far you can run in 10 seconds.?? ???? ??????? ???? ?????? ?? 10 ????? ……………………………………………………………Q2: Choose the correct answer for the following:???? ??????? ???????:1. ?The basic unit of length in the metric system is the ???? ???? ????? ?? ......A. yard.??B. liter.??c. gram.??d. meter. 2-Area is determined by multiplying length by??????? ???? ???? ????? ?? ........a. mass.??b. temperature.??c. width.??d. volume. Calculating VolumeCurriculum Standards: 17.1Objective: 1-Know how to calculate volume of regular and irregular solids, and liquids, and gases.????? ???? ????? ?????? ?????? ???????? ???? ???????? ???????? ????????. KEY WORDS??????Liter?????Meniscus????? ??????Length?????Width?????4822190175260 Liter: the basic metric unit for volume.????? :???? ?????? ???????? ?????. Meniscus: the curved surface of a liquid in a graduated cylinder ????? ?????? ??????: ?? ?????? ??? ?????? ?? ??????? ??????. Volume: the amount of space something takes up.?????: ????? ????? ???? ????? ?????.31623064135Measuring the volume of liquids: ???? ???????501967525400A graduated cylinder is used to measure the volume of a liquid. A graduated cylinder is a glass or plastic container that is marked with divisions. When a liquid is poured into a graduated cylinder, the surface of the liquid is curved. This curve is called the meniscus.Measuring cylinder ??????? ??????? ?????? ????? ??? ?????????????? ?????? ?? ????? ?? ????? ????? ???? ???? ????? ??? ??? ?????? ??? ???? ??? ?????? ????? ???? ???????? ???? ????? ??????.502920071755 To read the volume of a liquid, the surface of the liquid should be at your eye level. You should read the mark on the graduated cylinder closest to the bottom of the meniscus.?????? ??? ?????? ??? ?? ???? ???? ??????? ?? ????? ??? ?????? ??? ???? ??????? ?????? ???? ????? ?????? ?????? Volume of regular solids:The volume of a solid can be measured in cubic centimeters. ????????? ?????? ??? ?????? ?????? ???? ?????You can find the volume of a cube or a rectangular prism by multiplying its length by its width by its height. V= H X L X W??? ????????= ???????? x ?????x ?????3094990178435Calculate the volume of the rectangular ???? ????? V= H X L X WV= 5 X 2 X 3 = 30 cm3320929013335Calculate the volume of the rectangular………………………………………………………………………………………………………………………… Volume of irregular solids: ??? ?????? ?????? ??? ????????To measure the volume of irregular solids we can use a graduated cylinder.Pour water into a graduated cylinder. Measure the volume of the water (V1)Put the rock irregular object in the water. Then you read the volume of the water again (V2).The volume of the object is found; and forms the following equation:358584593980The volume of the object = V2-V1Volume of the rock =V2-V1Volume of the rock =40mL-30mL = 10 ml =10 cm3WorksheetQ1:Choose the correct answer in the following statements:???? ??????? ??????? ??? ??? ???:1-A measure of how much space something takes up is????? ?????? ???? ????? ??? ?? ??:a. mass.??b. length.??c. temperature.??d. volume.2-A graduated cylinder is used to measure??????? ?????? ?????? ????? : a.?mass.??b.?volume.??c.?length.??d.?temperature. 3-?To find the area of a rectangle you have to:????? ????? ???????? ??? ??: a. length length. ?b. length width.?c. square the width. d. length width x height4-?Volume can be measured in ???? ???? ????? ?????: a. cm3.??b. grams.??c. liters.??d. metersQ2: Complete the following: ???? ?? ??? There are…………milliliters in one liter.You can find the volume of a rectangular prism by multiplying its length by its width by it’s…………..One cubic centimeter is the same as …….milliliter.25CM is equal to………… ml10CM is equal to………….ml………….is used to measure the volume of a liquid.The basic unit of volume in the metric system is……………… Q3: Calculate the volume of the box in the diagram.???? ??? ??????? ?????? ?? ?????: …………………………………………………………………1cm2cm4 cm Curriculum standards: 17.3Objectives:1- Define density.????? ??????? 2- Know how to calculate the density of liquids, gases, and regular and irregular solids. ????? ???? ??????? ???????, ??????? ??????? ?????? ???????? ???? ????????.KEY WORDS??????Density???????Mass ??????Volume ?????Geologists need to measure the density of rocks. It helps them toIdentify the kind of rocks, and where it comes from.????? ????? ????? ??????? ???? ????? ?????? . ??? ??????? ??? ???? ????? ?????? ??? ??? ????. To measure density we use the formula:Density =mass/volume ???????= ?????? \ ?????3285490147320-15303549530How do you find the density of gases (air)?5208905495300Air is mixture of gases. To find the density of the air, follow the following steps: Find the mass of a closed flask using the balance m1???? ???? ???? ????Remove the air from the flask by a vacuum pump.???? ?????? ?? ??????Find the mass the empty flask m2???? ???? ?????? ??? ???? ?? ??????Calculate the mass of the air inside the flask The mass of the air = m1 – m2???? ???? ?????? ???? ????? ?????? To find the volume of the air is found by opening the clip under water so that water enters to replace the vacuum. Then pour the water into a measuring cylinder to find the volume.?????? ??? ?????? ?????? ?????? ?????? ?? ?????? ?????? ?? ???? ??? ????? ???????? ??????? ??????Use the formula: Density= mass/volume5208905147320How to find density of water?1. Find the mass of a dry empty beaker using a balance.???? ???? ????? ???????? ??????? 54749701130302. Use a measuring cylinder to pour exactly 100 ml (1 cm3) of water into the beaker.?? 100 ?? ?? ????? ?? ????? 3. Now find the mass of the beaker with the water in it.5276850104140???? ???? ????? ?????? ??? 4. Work out the mass of the water from the results of steps 1 and 3. ???? ???? ????? 5. Use the formula: density = Mass/volumeHow to find the density of irregular solid???? ???? ????? ??????? ?????? ??? ???????? .477964519050We can calculate the density of a stone.1. Find the mass of the rock using a balance.44570652800352. Find the volume of the solid by using a measuring cylinder and water. 3. Use the formula: density = Mass/volume???? ???? ????? ??? ????? ???? ????? ???????? ??????? ????? ????? ???????? ??????? ?????? ??? ?? ??????? ????????: ???????= ??????\ ?????WorksheetQ1:Choose the correct answer: 1. The density rule is: ????? ??????? ?? A-mass/volume b-volume/mass c-mass/weight d-volume×length 2. What is the unit of density? ?? ?? ???? ??????? a- g/kg b-g/cm3 c-g / km3 d-m/cm Q2: Define density? ?? ?? ??????? ………………………………………………………………………………………………………………………………… Q3: Calculate the density of a metal block that has a mass of 750g and a volume of 55 cm3? ?? ?? ????? ???? ?????? ??? ???? 750 ?? ???? 55 ??3? …………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………. Q4: Use the diagram to answer the questions below.?????? ????? ??????? ?? ??????? ???????: 20cm a-What is the volume of the bar? ?? ?? ??? ??????4257040182880………………………………………………………………………………..………………………………………………………………………….. b- If the bar has a mass of 5 grams, what is its density? ??? ???? ?????? 5 ?? ?? ?? ????????…………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………..When you walk at the seaside, do you feel lighter or heavier?????? ???? ??? ???? ????? ?? ???? ???? ??? ?? ???? ?????…………………………………… If you walk in deep enough, your feet come off the ground and you start to float. This is because of upthrust.??? ???? ?? ???? ???? ????? ????? ?? ????? ????? ?????? ???? ???? ??? ??? ?????Experiment:Hang an object in a spring balance and measure its weight??? ??? ?????? ?????? ??? ???? W1 = …………………..Lower the object into a beaker of water and measure its weigh again.?? ????? ?? ??? ?? ??? ??? ???? ??? ???? W2 = …………………..The weight of the object in water is………………..……??? ????? ?? ?????......................... Why?????? 430466595250Because of ……………………………………………Upthrust = W1 – W2The weight of an object is less in water because of the upthrust.The difference between the two readings is equal to the upthrus.????? ??? ????????? ?? ??? ????? If the weight of a rock is 2000 N. When you place the rock in water the weight will be 1200N??? ??? ??? ???? ?? 2000 ?????? ???? ????? ?? ????? ???? ????? 1200 ?????Calculate the upthrust? ???? ??? ????? ................................................................................................. ……………………………………………………………………………………………..Why the weight of the rock is less in water?????? ??? ????? ??? ?? ?????? ............................................................................................................. ................
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