Unit 1 Area, Volume, and Density

Transcription

1 Name: Date: 9/11 Period: Unit 1 Area, Volume, and Density Essential Questions: What is the difference between Area and Volume? What are the ways of finding volume? How does density help us to identify unknown materials? Do Now A floor tile has the dimensions 1m x 0.5m, what is its area? A box has the dimension of 1m x 0.5m x m, what is its volume? Slide 1

2 Review: How are base units different from other types of units? Base units are units used to measure base quantities Other units, like cm or cm, are made from the base unit of length the meter Slide Objectives Is this Review? Calculate areas of simple shapes Calculate volumes of prisms Explain how to measure volume using water displacement (or any liquid displacement) Define of density in words and mathematically Explain how density helps us to identify pure substances Slide 4

3 What is Area? Area is the size of a surface (like a wall or floor) You can calculate area of different shapes. There are different formulas for different shapes: Area of a Rectangle = Length x Width cm Area = (5 cm) x ( cm) = 15 cm cm You can also find area by counting unit squares: If each square has an area of 1 cm, the area is 15 cm Slide 5 What is Volume? Volume is amount of space an object occupies ( takes up ) You can calculate volume of different solid shapes. There are different formulas for different shapes: Volume of a Prism = Length x Width x Height Volume = (10 cm) x (5 cm) x (4 cm) = 00 cm cm cm cm You can also find volume by counting unit cubes: What is the volume of this prism? Slide 6

4 You can measure volumes of liquids using a graduated cylinder or a beaker Graduated cylinder is a tube that has a scale that matches a standard unit E.g., 1 milliliter () = 1 cm 1 Liter (L) = 1 m Beaker is another instrument used for measuring liquid volumes. Slide 7 Steps for making and recording any measurements 1. Zero or Calibrate Instruments. Check the value of the smallest division on the scale. Read scale (estimate) to 1/10 th of the smallest division 4. Record quantity label, value, and units Slide 8 4

5 How to measure liquid volumes Meniscus (mi-nis-kus) is a curved surface that you see when you put a liquid into a container. Always look at the scale at eye level, and read the bottom of the meniscus For example: Volume of water = cm = Slide 9 Why does a meniscus occur with liquids in containers? With most liquids, the attractive force between the liquid and the container is greater than the attraction between the individual liquid molecules. l Thus, the liquid "sticks" to the sides of the container at the edges. Slide 10 5

6 Measuring volume of objects using water displacement When a solid object does not have a regular shape, the easiest way to measure its volume: What is the original volume of the liquid? What is the liquid volume with the object fully submerged? What is the volume of the object? Slide 11 What is density? Density is how much mass is in 1 unit of volume. Which cube is more dense? Different pure substances have unique densities. You can find density to help you identify an unknown material. Slide 1 6

7 Mathematical definition of density Remember: You can either calculate volume of regular objects. You can also measure volume of irregular objects using water displacement. You can calculate density by dividing Mass by Volume Example: An object has a mass of 64.8 g and volume of 4 cm. What is the density of this object? M 64.8 g g g D.7.7 V 4 cm cm Slide 1 Identifying pure substances using density Use this table to identify the material of the object in the previous slide: Slide 14 7

8 Practice: Finding Area Find the area of each object. Use a ruler to measure dimensions. Show all work. Include units in the final answer. Slide 15 Practice: Calculating volume Find the volume of each object. Use a ruler to measure dimensions. Show all work. Include units in the final answer. 1. Volume =. Volume = Slide 16 8

9 Practice: Recording liquid volume measurements Slide 17 Practice: Measuring volume of objects using liquid displacement 1. Object Volume =. Object Volume = Slide 18 9

10 Wrap Up Is this Review? Calculate areas of simple shapes Calculate volumes of prisms Explain how to measure volume using water displacement (or any liquid displacement) Define of density in words and mathematically Explain how density helps us to identify pure substances Slide 19 10