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**Density **

We know that matter is anything that occupies a _______________ and has _________________.

Examples

What do we use density for?

Which one is more dense?

People in a square (popular place vs. not popular place)

How about this: Which square is more dense?

Which one is more dense?

Now which one is more dense?

A is more dense because for the small _________________ it holds, it has more___________________.

Even though they have the same _______________of particles, if A was the same size as B, A would have

____________________times as much particles.

What is density?

To find density, the amount of mass (a measurement if the particles present) is _____________by the volume of the substance. Density = mass/volume OR mass ÷ volume

_____________________ is measured in grams and kilograms.

_____________________ is measured in cubic centimeters or cubic milliliters.

Mass

Grams is represented as a___________ and Kilograms is represented as a _____________.

Volume

Cubic centimeters = ________ for a _________. Cubic milliliters = ______, for a __________.

___________mL = ______________cm 3

So if Density = mass/volume, Density = g/cm3 or g/ml

SI Units: International System of Units Modern metric system, measurements

Mass: ______________ = g and _________________ = kg

Length: ___________________ = m and _____________________= mm

Liquid: ________________ = L and ________________________ = mL

Time: _____________ = s and _____________________ = ms

Conversions

Milli = m __ centi= c __ Kilo =

Let’s try a density problem together k __

Frank has a paper clip. It has a mass of 9g and a volume of 3cm3. What is its density?

Frank also has an eraser. It has a mass of 4g, and a volume of 2cm3. What is its density?

Work on these problems:

Jack has a rock. The rock has a mass of 6g and a volume of 3cm3. What is the density of the rock?

Jill has a gel pen. The gel pen has a mass of 8g with a volume of 4cm3. What is the density of the gel?

Alicia has a watch. It has a mass of 4g and a volume of 2cm3. What is the density of the watch?

Mia has a wallet. It has a mass of 15g and a volume of 5cm3. What is the density of the wallet?

To actually calculate density we need measuring instruments.

To measure the mass, we need to use a _______________________.

If we use a _________________, we measure the _______________ of the object. The weight is the________________________ due to ______________________ pulling down.

You weigh _________________ on the moon because gravity is less. But the amount of particles you are made of doesn’t change.

Only mass is measured by the balance because the object’s _______________ counteract with the weights on the balance.

Measuring the ______________ of an object can be very tricky as well. Most objects are not regular shapes that we have formulas for to calculate the volume.

Volume for cube is V=___________________________x________________________x_____________________ and

Volume for cylinder is V=_______________________x_________________________x________________________.

Frank measured another eraser. He used a balance to measure the mass at 4g. However Frank is having trouble finding the volume. Can you help him?

Frank has a cup for soda. He wants to know how much soda the cup could hold so he measures the volume of the cup.

What is the volume?

What’s the area of a circle? A = ______________________x_______________or = __x__________x_________x_____

The volume is just the area of the base times the height. V = ________ x _______ x ____________;d is twice the

___________ so: d = 2 x r; r = d/2

Measuring Accuracy

There many type of errors

____________________________: The balance is not calibrated right

____________________________: mathematical, looking at the ticks on the instruments, eyes play trick on you.

When measuring Volume of liquids:

____________________: Bottom arch water of used for measuring volume.

Liquid Layers

If you pour together liquids that don’t mix and have different ___________________, they will form liquid layers.

When liquids don’t mix that means they’re _____________

The liquid with the highest density will be on the ____________________.

The liquid with the lowest density will be on the_______________.

Liquid Layers

Which layer has the highest density?

Which layer has the lowest density?

Which density would go with which layer?

Which liquid has the highest density?

Which liquid has the lowest density?

Which liquid has the middle density?

Liquid Layers – Try on your own!

Imagine that the liquids on the right have the following densities: Match the colors to the correct densities.

15g/cm3 _____________________________ 10g/cm3 _____________________________

3g/cm3 _____________________________ 9g/cm3 _____________________________

7g/cm3 _____________________________ 12g/cm3 _____________________________

Review

What is the formula for density?

What two methods can be used to measure volume?

What is a meniscus?

What happens if you pour together liquids that have different densities?

Will the liquid on the top have the highest or lowest density?

Will the liquid on the bottom have the highest or lowest density?

Super Scientist Question of the Day

Jake has a book, a ruler, and a balance.

How can Jake find the density of the book with the tools he has?

Practice Volume by displacement and density at: http://www.sciencejoywagon.com/explrsci/media/density.htm