# Density and its measurement Density 1 2 3

- Slides: 36

Density and its measurement

Density 1. 2. 3. What is density? How do you measure density? Measuring the densities of objects Why do some things float and some things sink?

Density is a measure of how much stuff (mass) is packed into a certain space. Look at the two metal blocks-they both have the same mass Why does the aluminium block take up more space?

Copper atoms are heavier than aluminium atoms So we need more Aluminium to make 1 kg of material

Which one is MORE dense? • If each box has the same volume, and each ball has the same mass, which box would weigh more? Why?

Summary • Density tells us how much stuff is packed into a certain space Density changes because either: • The materials are different and the atoms have different masses • The way the particles are arranged is different (more or less spread out)

The “DMV” Triangle for Volume, Mass, and Density = Volume = Mass Volume Mass Density Mass ==Density x Volume M ÷ ÷ D X V

• Mass is measured in Kilograms (kg) • Volume is measured in Metres cubed (m 3) ) • Density is measured in Kg/m 3

Changing units From grams to kilograms ------divide by 1000 350 g 0. 350 kg

From cm 3 to m 3 --------divide by 1, 000 25 cm 3 0. 000025 m 3

Examples: A block of lead has a mass of 44000 kg and a volume of 4 m 3. What is the density of lead?

An ‘empty’ bedroom measures 5 m x 4 m x 2. 5 m. If the density of air is 1. 3 kg/m 3 what is the mass of air in the room?

A piece of anthracite has a volume of 15 cm 3 and a mass of 27 g. What is its density in kg/m 3 ?

Density of a regular solid • Find the mass of the object by putting it on the balance • Find the volume by measuring the length of the three sides with a ruler and then calculating the volume (l x w x h) • Calculate the density –remember to keep your units correct!

What is the resolution of the rulers in the picture?

What is the smallest change in mass that this balance could measure? If the mass of our object is several grams then this resolution is good enough

Determination of Certain Digits 10 m. L graduated cylinder volume is 6. 62 m. L 100 m. L graduated cylinder volume is 52. 7 m. L

Viewing the Meniscus Correct: viewing the meniscus at eye level. Incorrect: viewing the meniscus from an angle.

Viewing the Meniscus Viewing the meniscus from an angle can lead to false readings of the volume.

Micrometer screw gauge

v 3. 24 mm 7. 5+28× 0. 01 Answer=7. 78 mm =7. 79 mm

Measuring the density of a liquid zero burette zero Measuring cylinder A burette can be used to measure the volume of a liquid more accurately

• • Fill a burette with water and let it run into a beaker to remove the air bubbles Read and record the volume of water in the burette Find the mass of an empty beaker Allow some water from the burette to run into the beaker Record the reading on the burette Reweigh the beaker to find the mass of water Calculate the density of water

Filling A Buret To fill a buret, close the stopcock at the bottom & use a funnel. You may need to lift the funnel slightly to allow the solution to flow freely into the buret.

Air Bubbles in the Buret Tip Check the tip of the buret for an air bubble. To remove an air bubble, tap the side of the buret tip while solution is flowing.

Reading the Buret Hold a buret reading card behind the buret. Move the card until you can easily see the meniscus. Read the buret from top to bottom. This buret reads 11. 34 m. L

Finding the density of an irregular solid-method 2 • • or Find the mass of the solid using the balance Fill the Eureka can with water Lower the solid into the water Measure the displaced water volume in the measuring cylinder • Fill a small beaker almost full with water • Lower it into a large beaker-carefully top up the water • Lower the solid into the water • Pour the displaced water into a measuring cylinder and measure the volume

DENSITY OF AN IRREGULAR SOLID m = 360 g n Find the Mass of the solid 80 cm 3 50 cm 3 on a balance. n. Fill the Measuring Cylinder with Water to a known Volume. n Add the Object. n Work out the Volume of Water that is displaced. n Calculate the Density.

lock fixed scale vernier scale jaws Vernier Caliper

Main Scale Vernier Scale

13

13. 650 mm

23

23. 700 mm

48. 550 mm

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- Linear density of fcc 111
- Linear atomic density
- Is dense
- Closeness of a measurement to the true value
- The emigree
- Its halloween its halloween the moon is full and bright
- Physiological density vs arithmetic density
- Nda full dac
- Physiological density ap human geography
- When a train increases its velocity, its momentum
- Sunny windy rainy cloudy
- If its square its a sonnet summary
- Its not easy but its worth it
- Progress and performance measurement and evaluation
- Progress and performance measurement and evaluation
- Pressure formula
- Chapter 7 work design and measurement
- Significant figures rules
- Direct and indirect measurement
- Process instrumentation ppt
- If you can't measure it you cannot improve it
- Concept map of measurement assessment and evaluation
- Nominal scales
- Measurement and scaling
- Measurement and analysis of online social networks
- Primary scales of measurement
- What is comparative scale
- Kcapanse
- Result approach in measuring performance
- Tolerance ratio
- Measurement and scaling
- Approaches to measuring performance
- Forecasting and demand measurement in marketing
- Circles geometric measurement and geometric properties
- Sturdy and durable displacement measurement
- Displacement