W1 - Lesson 1: Mass, Volume, And Density

ScienceV5-07Grade 8W1 - Lesson 1: Mass, Volume, andDensity

Important Concepts of Grade 8 ScienceW1 - Lesson 1 . Mass, Volume, and DensityW1 - Lesson 2 . Solubility and Saturation PointsW1 - Lesson 3A . Viscosity, Flow Rate, and BuoyancyW1 - Lesson 3B . Simple MachinesW1 - Lesson 4 .Gears, Mechanical Advantage, Speed Ratios, and EfficiencyW1 - Lesson 5 .Hydraulics and PneumaticsW1- QuizW2 - Lesson 1 .The Role of Cells within Living Things, Cells-Tissue-Organ SystemW2 - Lesson 2 . The MicroscopeW2 - Lesson 3 . Body Systems Part 1W2 - Lesson 4 . Body Systems Part 2W2 - Lesson 5 . Problems Associated with Body SystemsW2 - QuizW3 - Lesson 1 .Transmission and Absorption of LightW3 - Lesson 2 . Reflection and Refraction of LightW3 - Lesson 3A .Vision and LensesW3 - Lesson 3B . Water in its Various States Affects Earth’s Landforms and ClimateW3 - Lesson 4 . Adaptations to Aquatic EcosystemsW3 - Lesson 5 . Water QualityW3 - Quiz .MaterialsRequiredTextbook:Science inAction 8Science Grade 8Version 5Preview/Review W1 - Lesson 1Publisher: Alberta Distance Learning CentreAuthor: Kevin De ClerqIn-House Teachers: Barb Philips and Norene PinderProject Coordinator: Dennis McCarthyPreview/Review Publishing Coordinating Team: Nina Johnson,Laura Renkema, and Donna SilgardThe Alberta Distance Learning Centre has an Internet site that you may find useful. The address is as follows: http://www.adlc.caThe use of the Internet is optional. Exploring the electronic information superhighway can be educational and entertaining. However, beaware that these computer networks are not censored. Students may unintentionally or purposely find articles on the Internet that maybe offensive or inappropriate. As well, the sources of information are not always cited and the content may not be accurate. Therefore,students may wish to confirm facts with a second source.ALL RIGHTS RESERVEDCopyright 2007, by Alberta Distance Learning Centre, 4601-63 Avenue, Barrhead, Alberta, Canada, T7N 1P4. Additional copiesmay be obtained from the Alberta Distance Learning Centre.No part of this courseware may be reproduced or transmitted in any form, electronic or mechanical, including photocopying (unlessotherwise indicated), recording, or any information storage and retrieval system, without the written permission of Alberta DistanceLearning Centre.Every effort has been made both to provide proper acknowledgement of the original source and to comply with copyright law. Ifcases are identified where this effort has been unsuccessful, please notify Alberta Distance Learning Centre so that appropriatecorrective action can be taken.IT IS STRICTLY PROHIBITED TO COPY ANY PART OF THESE MATERIALS UNDER THE TERMS OFA LICENCE FROM A COLLECTIVE OR A LICENSING BODY.

Preview/Review ConceptsforGrade Eight ScienceW1 - Lesson 1:Mass, Volume, and Density

OBJECTIVESBy the end of this lesson, you should determine the mass of matter determine the volume of liquid and of a regularly or irregularly shapedsolid know units of volume for solids, liquids, and gases calculate the density of a substance identify an unknown, pure substance from its density prepare and use a volume-mass graphGLOSSARYdensity - mass and/or volume; themass per unit volume of asubstancemass - the amount of matter in asubstancevolume - the amount of spaceoccupied by something

Preview/Review Concepts W1 - Lesson 1Science Grade 8W1 - Lesson 1: Mass, Volume, and DensityWelcome to W1 - Lesson 1. This lesson teaches you about mass,volume, and density. These concepts are needed for other topicsthroughout this course. This lesson should take about 1.5 hours.MassMass is the measure of the amount of matter in an object, usuallygiven in grams (g) or kilograms (kg). For example, if you weighed aguinea pig on a balance scale, you might find its mass is 250 g.Mass varies greatly. A feather may have a mass of less than agram; a semi-truck has a mass of several tonnes.Developed by Alberta Distance Learning Centre .1

Science Grade 8Preview/Review Concepts W1 - Lesson 1Activity 1In the Item column list some things that have mass. In the lastcolumn write an estimate of the mass of the item/object. Includethe units (g, kg, tonnes). The first one is an example.Number1Itemcell phoneEstimatedMass300 g234567891011If you are still unclear about the concept of mass, ask your teacherquestions about this.2. Developed by Alberta Distance Learning Centre

Science Grade 8Preview/Review Concepts W1 - Lesson 1VolumeYou might think of volume as that little dial on a stereo thatcontrols the sound. However, for the purposes of this course, volumeis an amount of space. The volume of an object is the amount ofspace it occupies. For solid objects the units are cubic such as cubiccentimetres (cm3) or cubic metres (m3). Liquids volumes are givenin units such as millilitres (mL) or litres (L). Gases are measuredby both liquid and solid units.When reporting volume with a unit such as cm3, that cube (thelittle 3) means that three things were used to calculate it.This general formula can be used to calculate volume of arectangular solid:volume length x width x heightSo, if you have a rectangular solid with the dimensions3 cm x 6 cm x 7 cm, its volume would be 126 cm3.Note: 1 cubic centimetre (1 cc) 1 mLWhen you calculate the volume of a rectangular solid, length,width, and height must be in the same units. For example, if lengthis 5 cm, width is 12 cm and height is 2 m, you must convert themetres (m) in the height measurement into centimetres (cm) orthe centimetres (cm) in the length and width measurements intometres (m) to have a correct answer. For example, the 2 m convertsinto 200 cm, so your new dimension for the calculation would be:5 cm x 12 cm x 200 cm 12000 cm3If you are not sure how to convert metric units, ask your teacher forassistance. Ten millimetres make 1 centimetre; 100 centimetresmake 1 metre; 1 000 metres make 1 kilometre.Conversion Practice1. 55 mm cm2. 1.20 m cm3. 230 m km4. 0.5 km cmLiquid volumes are measured in containers with volume markings.The volume is read at the surface of the liquid. Read the volumesection of Toolbox 5 on page 424 of the text.Developed by Alberta Distance Learning Centre .3

Science Grade 8Preview/Review Concepts W1 - Lesson 1Activity 2Using your calculator, calculate volume for the following. Be sureyou include the proper units and conversions. The first one hasbeen done for 12m10m12m91cm25m235cm27km33km44mThe numbers in the chart are quite large, but they are not out ofthe ordinary. You may see numbers this large if you calculate thevolume of a swimming pool or perhaps determine the amount of topsoil on a parcel of land.The mass of an object (solid, liquid or gas) stays the same regardlessof where the object is located. The volume of a solid is also constant.Weight will change with location. The more the gravitational pullon a mass, the greater its weight will be. A cubic metre of anythingactually weighs less on a mountain top!4. Developed by Alberta Distance Learning Centre

Science Grade 8Preview/Review Concepts W1 - Lesson 1DensityIf someone told you they thought you were dense, you probablywould not like it at all. However, every object has density– somelow, some high. What does this mean? For something to have ahigh density, it must have a small volume compared to its mass. Ifsomething has a low density, it has a large volume compared to itsmass. Styrofoam has a low density. You could probably lift a pieceof styrofoam the size of a car with little effort. However, a piece ofgold the size of a car would be very difficult to lift due to its highdensity.Density can be calculated. Density is the mass per unit of volume.It is usually measured in grams per millilitre (g/mL) or kilogramsper litre (kg/L) for liquids or gases. The units for density of solidsare usually grams per cubic centimetre (g/cm3) or kilograms percubic metre (kg/m3).This formula can be used to calculate density:density (d) mass (m)volume (v)Example:If a 10g object occupies 2.5 cm3 what is its density?mv10 gd 2.5 cm 3d 4 g/cm 3d For calculations of density, all the units you use must becomparable. This means that if the mass is in grams, the volumemust be in mL or cm3. If the mass is in kilograms, the volume mustbe in L or m3.The following is an example of a student’s calculation of the densityfor a small rock. The student used the water displacementmethod. This method works on the theory that when an object isdropped into water, it will displace (move) an amount of water thatis equal to its volume. This is shown when you get into a bathtubfilled with water and you notice the water level has risen. The partsof your body that are under water have displaced an amount ofwater equal to their volume. This is the best way to determine thevolume of an irregular object such as a rock.Developed by Alberta Distance Learning Centre .5

Science Grade 8Preview/Review Concepts W1 - Lesson 1ExamplesA student used the water displacement method to determine thevolume of a rock. First, 50 mL of water were added to a graduatedcylinder. Then the rock was dropped in. The water then measured62 mL. What is the volume of the rock?62 mL – 50 mL 12 mLThe rocks volume is 12 mL.Since 1 mL is the same as 1 cc, the volume of the rock can alsobe written as 12 cc.The student found that the volume of the small rock was 47 mL. Byusing a balance beam scale, the student determined that the rock’smass was 78 g.Using the above formula for density, the student calculated thefollowing result: d m/v78 gd 47 mLd 1.659 g/mLd 1.66 g/mL(rounded to 2 decimal places)Therefore, the rock was 1.66 times more dense than the samevolume of water. We know that the density of water is 1 gram permillilitre.Scientists have used density to help them identify elements suchas gold and silver because under the same conditions, densityis a constant value. It never changes unless conditions such astemperature change. Pure gold will always have a density equal to19.3 g/cm3 at room temperature. If a shiny gold-coloured metal hasany other density, the substance is not pure gold. In the followingactivity, you will calculate the actual densities of some importantelements.Questions1. What is the volume of an object given the following information?Initial water volume 25 mL, Final water volume 35 mL.6. Developed by Alberta Distance Learning Centre

Science Grade 8Preview/Review Concepts W1 - Lesson 12. 50 mL of water is added to a measuring container.After a 30 cc object is added, what volume will the water read?Activity 3A student took some unknown pure substances and used thewater displacement method to determine their volumes. Then,the student found the mass of each sample. Using a calculator,determine the density of the following samples. Then determine thename of each element - using the chart on the next page. The firstone has been done for you.SampleMass 7Possible name ofElementironDeveloped by Alberta Distance Learning Centre .7

Science Grade 8Preview/Review Concepts W1 - Lesson ensity 3.719.14.542.7Activity 4A student recorded the mass and volume of differentamounts of silver. On the grid provided, graph thevolume numbers 2, 6, 10, 14, 18, and 20 on thex axis (the bottom) and the correspondingmass numbers on the y axis, (alongthe side). This is a line graph; youmust label your axis and units.Your graph must include a title(Density of Silver). Whenyour graph is complete,you must answer thequestions followingit. The data tableshowing theinformationthe studentcollectedis on thenext page.8. Developed by Alberta Distance Learning Centre

Science Grade 8Preview/Review Concepts W1 - Lesson 510.510.510.510.510.510.510.510.5Developed by Alberta Distance Learning Centre .9