Grade 7 Unit P.1 - Measurement & Density. Grade 7 Measurement and Density

Transcription

1 Grade 7 Measurement and Density - 1 -

2 Curriculum standards: 17.1, 17.2 Objectives 1-Know how to measure length and calculate area of ك ف خ ق بش انطىل وحسبة ان سبحخ نألجسبو ان تظ خ objects. regular 2-Express large and small units using appropriate prefixes. انتؼج ر ػ انىحذاد انكج رح وانصغ رح ثبستخذاو انجىادئ ان بسجخ. KEY WORDS Meter Unit Area ان ؼ ى ان تر وحذح يسبحخ Measuring 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. ان ظبو انؼبن هى شكم حذ ث نه ظبو ان تري و ستخذو وحذاد ي يضبػفبد. 10 Prefixes are used to change the size of a انجىادئ تستخذو نتغ ر حجى انىحذح. unit. The three basic quantities we have to measure in physics are length, mass, and time. How do you measure - 2 -

3 length? Length is measured in a unit called the Metre (M). ان تر هى وحذح ق بش انطىل األسبس خ Rulers are used for measuring length. The ruler shows only centimeters & millimeters not meters Ruler To measure large lengths you can use a metre ruler or a measuring tape or trundle wheel. To measure small lengths you can use Metre ruler Measuring tape Trundle wheel micrometer. Micrometre How do you calculate Area? Area of a rectangle= length x Width Area is measured in square units, such as square meters (m 2 ). يسبحخ ان ستط م= انطىل X انؼرض ان سبحخ تقبش ثبنىحذاد ان رثؼخ يثم ان تر ان رثغ Calculate the area of the following احسة ساحح ا ستط ١ ا تا rectangle

4 Worksheet Q1: 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. لديك مجموعة من األدوات لقياس الطول Micrometer Trundle wheel Which would you use to measure the following distances? أي األدواخ عىف تغتخذو نقياط ان غافاخ انتانيح The distance traveled by a snail in 5 minutes? ان غافح انتي يقطعها انحهضو في خ ظ دقائق قطش عهك wire? The diameter of a يحيظ عاحح ان ذسعح ground? The circumference of the school طىنك Your height عشض وسقح paper. The width of a How far you can run in 10 seconds. 10 تثهػ كى ان غافح انتي تقطعها في ثىا - 4 -

5 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.... اختر االجبثخ انصح حخ : وحذج قياط انطىل هي 2-Area is determined by multiplying length by... a. mass. b. temperature. c. width. d. volume. ان غاحح تخحذد تضشب انطىل في - 5 -

6 Calculating Volume Curriculum Standards: 17.1 Objective: 1-Know how to calculate volume of regular and irregular solids, and liquids, and gases. ك ف خ حسبة انحجى نه ىاد انصهجخ ان تظ خ وغ ر ان تظ خ وانسبئهخ وانغبز خ. KEY WORDS Liter Meniscus Length Width ان ؼ ى انهتر انسطح ان قؼر انطىل انؼرض Liter: the basic metric unit for volume. ا تش : حذج ا م ١ اط األساس ١ ح حج. Meniscus: the curved surface of a liquid in a ا سطح ا معش سائ : ا ح اء سطح ا سائ ف graduated cylinder ا خثاس ا ذسج. Volume: the amount of space something takes up. ا حج : مذاس ا ح ١ ض ا ز شغ ا جس

7 حجىو انسىائم liquids: 1- Measuring the volume of A 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. ٠ ستخذ ا خثاس ا ذسج م ١ اط حج ا سائ ا خثاس ا ذسج عثاسج ع أ ث ب صجاج مس عذج ألسا ع ذ ضع ا سائ ف ١ ٠ صثح سطح ا سائ ح زا اال ح اء ٠ س ا سطح ا معش. Measuring cylinder 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. مشاءج حج ا سائ ٠ جة ا ٠ ى تى ا ع ١ ا ف ست سطح ا سائ ا مشأ ا عال ح األلشب ماع ا سطح ا معش سائ 2- Volume of regular solids: The volume of a solid can be measured in cubic centimeters. حج ا اد ا ص ثح تماط ت حذج ا س ت ١ تش ا ىعة 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 حجى ان ستط م= االرتفبع x انؼرضx انطىل Calculate the volume of the ا جذ ا حج rectangular V= H X L X W V= 5 X 2 X 3 = 30 cm 3 Calculate the volume of the rectangular - 7 -

8 حجى ان ىاد انصهجخ غ ر ان تظ خ solids: -3 Volume of irregular To measure the volume of irregular solids we can use a graduated cylinder. 1. Pour water into a graduated cylinder. 2. Measure the volume of the water (V1) 3. Put the rock irregular object in the water. 4. Then you read the volume of the water again (V2). 5. The volume of the object is found; and forms the following equation: The volume of the object = V2-V1 Volume of the rock =V2-V1 Volume of the rock =40mL-30mL = 10 ml =10 cm3 Worksheet Q1:Choose the correct answer in the following statements: اختر اإلجبثخ انصح حخ نكم ي ب ه : 1-A measure of how much space something takes up is يقياط انفشاغ انزي يشغهه جغى يا هى : a. mass. b. length. c. temperature. d. volume. 2-A graduated cylinder is used to measure ان خثاس ان ذسج يغتخذو نقياط : a. mass. b. volume. c. length. d. temperature

9 3- To find the area of a rectangle you have to: : يجة نقياط يغاحح ان غتطيم a. length length. b. length width. c. square the width. d. length width x height 4- Volume can be measured in ي ك قياط انحجى تىحذج : a. cm 3. b. grams. c. liters. d. meters أك م يب ه following: Q2: Complete the 1. There are milliliters in one liter. 2. You can find the volume of a rectangular prism by multiplying its length by its width by it s.. 3. One cubic centimeter is the same as.milliliter CM is equal to ml 5. 10CM is equal to.ml 6..is used to measure the volume of a liquid. 7. The basic unit of volume in the metric system is Q3: Calculate the volume of the box in the diagram. احست حجى انص ذوق ان ج ف انشكم : 1cm 4 cm 2cm - 9 -

10 Curriculum standards: 17.3 Objectives: تؼر ف انكثبفخ. density -1 Define 2- Know how to calculate the density of liquids, gases, and regular and irregular solids. ك ف خ حسبة انكثبفخ نهسىائم, انغبزاد وان ىاد انصهجخ ان تظ خ وغ ر ان تظ خ. KEY WORDS Density Mass Volume ان ؼ ى انكثبفخ انكتهخ انحجى Geologists need to measure the density of rocks. It helps them to Identify the kind of rocks, and where it comes from. ع اء دساسح األسض ٠ حتاج ل ١ اط وثافح ا صخ س. زا ٠ ساعذ ع تحد ٠ ذ أ اع ا صخ س أ ٠ تأت. To measure density we use the formula: Density =mass/volume انكثبفخ= انكتهخ \ انحجى How do you

11 find the density of gases (air)? Air is mixture of gases. To find the density of the air, follow the following steps: 1. Find the mass of a closed flask using the balance m1 ا جذ وت ح د سق فاسغ 2. Remove the air from the flask by a vacuum pump. افشغ ا ذ سق ا اء 3. Find the mass the empty flask m2 ا جذ وت ح ا ذ سق فاسغ ا اء 4. Calculate the mass of the air inside the flask The mass of the air = m1 m2 احسة وت ح ا اء ا ز تذاخ ا ذ سق 5. 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. ال ٠ جاد حج ا اء استثذي ا اء ا ضاي ا ذ سق تا اء ث ا حذ حج ا اء تاستخذا ا خثاس ا ذسج 6. Use the formula: Density= mass/volume How to find density of water? ا جذ balance. 1. Find the mass of a dry empty beaker using a وت ح ا ىأط ا جاف تاستخذا ا ١ ضا 2. Use a measuring cylinder to pour exactly 100 ml (1 cm 3 ) of ضع 100 ا اء ف ا ىأط beaker. water into the 3. Now find the mass of the beaker with the water in it. ا جذ وت ح ا اء ا ىأط عا 4. Work out the mass of the water from the results of steps ا جذ وت ح ا اء.3 1 and 5. Use the formula: density = Mass/volume

12 How to find the density of irregular solid?.ك ف ن و ج ود ح كثبف األجسبو انصهجخ غ ر ان تظ خ We can calculate the density of a stone. 1. Find the mass of the rock using a balance. 2. Find the volume of the solid by using a measuring cylinder and water. 3. Use the formula: density = Mass/volume ك حسبة كثبفخ حصى ثق بش كتهخ انحصى ثبستخذاو ان سا وحسبة انحجى ثبستخذاو ان خجبر ان ذرو وي ثى استخذاو ان ؼبدنخ: انكثبفخ = انكتهخ\ انحجى Worksheet Q1:Choose the correct answer: is: 1. The density rule لا ا ىثافح A-mass/volume b-volume/mass c-mass/weight d-volume length density? 2. What is the unit of ا حذج ا ىثافح a- g/kg b-g/cm 3 c-g / km 3 d-m/cm يب ه انكثبفخ density? :Q2 Define Q3: Calculate the density of a metal block that has a mass of 750g and a volume of 55 cm3? 3 يب ه كثبفخ قطؼخ يؼذ خ نهب كتهخ 750 غى وحجى 55 سى

13 Q4: Use the diagram to answer the questions below. استخذو انشكم نإلجبثخ ػ األسئهخ انتبن خ : ا حج ا مطعح bar? a-what is the volume of the 20cm.... b- If the bar has a mass of 5 grams, what is its إرا وا ت وت ت ا 5 غ ا وثافت ا density?.. When you walk at the seaside, do you feel lighter or heavier? ع ذ ا ت ش ع شاطئ ا ثحش تشعش تأ ه أخف أ أثم ص ا ا If you walk in deep enough, your feet come off the ground and you start to float. This is because of upthrust. إرا ش ١ ت ف ١ ا أع ك تشتفع لذ ان ع ا ماع تثذأ تا طف ر ه تسثة ل ج دفع ا اء

14 Experiment: 1- Hang an object in a spring balance and measure its weight ع ك جس ت ١ ضا ص ثشو ع ١ ص W1 =.. 2- Lower the object into a beaker of water and measure its weigh again. ضع ا جس ف وأط ت اء ع ١ ص شج اخش W2 =.. The weight of the object in water is.. وص انجغى في ان اء =... ن ارا Why? Because of Upthrust = W1 W2 The weight of an object is less in water because of the upthrust. The difference between the two readings is انفرق ث انقرائت هى قىح انذفغ upthrus. equal to the If the weight of a rock is 2000 N. When you place the rock in water the weight will be 1200N ارا وا ص صخشج ١ ت 2000 ع ذ ضع ا ف ا اء اصثح ص ا ١ ت 1200 احسة ل ج ا ذفع upthrust? 1. Calculate the..... ارا ص ا جس أل ف ا اء water? 2. Why the weight of the rock is less in