Mass, volume and density revised
- 1. Mass, Volume, & Density What makes the ice cubes float in your water?
- 2. Mass of an Object Matter – A substance that occupies or takes up space. Anything that takes up space has matter. Mass - is the amount of matter an object has. Who has more mass?
- 3. What is an SI-Unit? SI Unit is the unit we use to measure something. (Quantitative Assessment) Examples: 1. Time: Minutes, Seconds, Days, Weeks 2. Distance: Feet, Meters, Yards, Miles, Light Years 3. Area: Square feet, Square inches When you measure in science, you must know and use the correct SI Unit!!!
- 4. Mass Mass is measured in grams or Kg. We will measure mass using a triple beam scale. Unlike weight, mass is constant everywhere in the universe. You always have the same mass!!
- 5. Weight Weight-is the amount gravity pulls on an object. It is not constant. Why?? Look at the picture and tell me. What is the factor that changes?
- 6. Triple Beam Scale Make sure to start off zeroing the scale. To find mass: Go to biggest way and work your way down the scale to smallest until it is balanced.
- 7. Volume Volume - is a measurement of the amount of space an object takes up or occupies. It can have different SI units depending on if it is regularly shaped or irregular shaped. It will be either CM3 or ML.
- 8. Liquid Volume To measure a liquid we will use a graduated cylinder. *Tip* get on eye level with the liquid to take an exact measurement. Unit for liquid is mL
- 9. Regular Shaped Solid Volume Any object that you can measure L x W x H An example would be a cube. You measure the L x W x H and Multiply. This will give you the unit cm3.
- 10. Irregular shaped object Can You measure L x W x H of these objects? How can you find the volume then?
- 12. Water Displacement Fill a graduated cylinder up with water. Ex: 50 ML Drop the object in and observe the new water level. Ex: 60 ML. Subtract and you have the volume of the object.
- 13. Density Density: 2 ways to view it 1. The mass of a substance per unit volume 2. How many particles there are in a area of space. Units: g/cm3 or g/mL, depending if you use L x W x H or water displacement for volume
- 14. Density equation Density - is an objects ratio of its mass to volume. Mass per unit Volume Density= Mass/Volume.
- 15. Density Triangle How to use: 1. Cover up the term you are looking for. 2. Use the two other variables to find the one you are looking for. 3a. If they are beside each other then multiply. 3b. If one is on top of the other then divide it by the bottom one.
- 16. Density Example Mass of wool ball (Irregular): 103 grams Volume of wool ball: 2000mL What is the density? Density = 103g /2000 mL Density = 0.05 g per mL. Which can be written as 0.05 g/mL
- 17. A regular Shaped object A cube with a volume of 6 cm3 The cube has a mass of 18 grams. D=M/V D=18grams/6 cm3 D = 3g/cm3
- 18. Density Example 2 A 275 g object occupies a volume of 250 mL. What is the density?
- 19. How to change Density 2 Ways Change the mass or change the volume. Both will effect the overall density.
- 20. Change the Mass If we increase mass then we increase density If we decrease mass we decrease density Look at example below: Left has less mass and right has more mass. Which has the most density?
- 21. Change the Volume Increasing the volume will decrease the density Decreasing the volume will increase the density. Look at example below: Left has increased volume and right has decreased volume.
- 22. Hmmm… So What makes your ice float?