read & learn

Read & Learn

Read the provided article.

Use the information in the reading to answer the questions on the task cards on your answer sheet.

Make sure your answers in the correct spot on the answer sheet.

M. Poarch 2016 - science-class.net – Permission granted to copy for non-profit, education use only

Density

Every object on earth is made of atoms. Gravity pulls these atoms to the earth. You can measure the pull of gravity on an object – we call that measurement weight.

Density is how close together the molecules of a substance are or how much mass a substance has in a given space. If you have one cup of jelly beans and one cup of marshmallows…the jelly beans have more mass…there is more “stuff” compacted into the cup. The marshmallows are mostly air. If you put each of those cups in a microwave to melt…the sugar and water that makes up the jelly beans would almost fill the cup to the top. The sugar and water that makes up the marshmallows would only fill the cup a little bit because marshmallows have less mass, they are mostly made of air. Materials with more density weigh more. A cup of jelly beans weighs more than a cup of marshmallows.

• Density is a measurement of how solid something is. Specifically it is the mass per unit volume of a substance. If you have two objects of the exact same size (volume), the more dense object will weigh more than the less dense object.

• So there are two things contributing to density:– The mass of the atoms or molecules that makes up the material.– The volume or amount of space the material takes up. If the molecules or atoms are “packed” in more closely, it will be more

dense.

• For example, Styrofoam is a low density material. Even a large styrofoam container does not weigh much. The molecules in the Styrofoam do not have much mass and there is a lot of space between them. A brick, on the other hand, is much more dense. Even a moderate sized brick can be pretty heavy. This is because the molecules which make up the rock have more mass and are packed more closely together.

http://www.indypl.org/kids/blog/?p=9042 & http://the-science-mom.com/


http://www.indypl.org/kids/blog/?p=9042

http://the-science-mom.com/

What is WEIGHT?What is MASS?

What is VOLUME?

Describe DENSITY.

Two objects have the same volume.

Object A has a mass of 10 g.Object B has a mass of 20 g.

Which object has the greatest density?

Two objects have the same mass.Object A has a volume of 20 cm3.

Object B has a mass of 40 cm3.Which object has the greatest

density?

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Watch & Learn

Watch the video at this link: https://www.youtube.com/watch?v=H2Rlt3YM1To

Use the information in the video to answer the questions on the task cards on your answer sheet.



https://www.youtube.com/watch?v=H2Rlt3YM1To

How do you calculated density? What is the formula?

Complete this sentence:Density is a combination of

__________ and __________.

Density is a defining characteristic of a substance.

What does this mean?

What does density predict?

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Explore & Learn

Observe the tank of water and soda cans.

Use your observations to answer the questions on the task cards.



The can of regular soda sinks in water. What does this observation tell you about the density of the

can of soda compared to the density of water?

The can of diet soda floats in water. What does this observation tell you about the density of the

can of diet soda compared to the density of water?

Use the terms mass, volume, and density to explain why adding bubble wrap makes a can of regular soda float in water.

Use your observations to infer why life jackets are made of lightweight material and are

large.

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Explore & Learn Again

1. Drop the marble in the cup of water.2. Observe.3. Add bubble wrap to the marble and

repeat.

Answer the questions on the task cards.Make sure your answers in the correct spot on the answer sheet.


The marble originally sunk in water. What can you say about the density of the marble compared to

the density of water?

After adding bubble wrap your marble floated. What can you say

about the density of theMarble-and-bubble wrap

compared to the density of water?

Density is the relationship between the mass of an object and its volume.

When you add material to your sinking object, what do you change more, mass or

volume?

How does increasing the volume of an object

affect its density?

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Investigate & Learn

Perform the investigation. It has TWOparts.Answer the questions on the task cards for part 1, for part 2, and then for the conclusion cards.Make sure your answers in the correct spot on the answer sheet.


Investigate & Learn

Procedure Part 1 – read the entire procedure before you begin.

1. Fill 2 clear plastic cups about 2/3 of the way with room temperature water.

2. Fill one dropper with cold water that has been colored blue. Poke the end of the dropper a little beneath the surface of the colorless room-temperature water.

3. While observing from the side, gently squeeze the dropper so that the cold water

slowly flows into the room-temperature water.

4. Fill another dropper with hot water that has been colored red. Poke the end of the dropper a little beneath the surface of this same cup of room-temperature water.

5. While observing from the side, gently squeeze the dropper so that the hot water

slowly flows into the room-temperature water. Hold a blank piece of paper behind the cups to help you see the colored water.

Investigate & Learn

Perform the investigation. It has TWOparts.Answer the questions on the task cards for part 1, for part 2, and then for the conclusion cards.Make sure your answers in the correct spot on the answer sheet.


Investigate & Learn

Procedure Part 2 – read the entire procedure before you begin.

1. Fill 2 clear plastic cups about 2/3 of the way with room temperature water.

2. Fill one dropper with cold water that has been colored blue. Push the end of the dropper to the bottom of the cup of the colorless room-temperature water.

3. While observing from the side, gently squeeze the dropper so that the cold water

slowly flows into the room-temperature water.

4. Fill another dropper with hot water that has been colored red. Push the end of the dropper to the bottom of the cup of the colorless room-temperature water.

5. While observing from the side, gently squeeze the dropper so that the hot water

slowly flows into the room-temperature water. Hold a blank piece of paper behind the cups to help you see the colored water.

Part 1 -

Color in and label areas of the cup to show where the colored hot and cold water ended up

after you released them into the room temperature water.

Part 1 -

Describe the movement of the hot and cold water after each

liquid was released.

Part 2 -

Color in and label areas of the cup to show where the colored hot and cold water ended up

after you released them into the room temperature water.

Describe the movement of the hot and cold water after each

liquid was released.

Part 2 -

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Investigate & Learn

After you have completed both Part 1 and Part 2, complete the conclusion cards/


Which temperature of water is MOST dense?

Which temperature of water is LEAST dense?

If you went scuba diving, would you expect the water temperature to get warmer orcolder as you dove deeper beneath the surface? What evidence do you have from your investigation to support this?

During late fall and early winter, the water at the surface of a lake may suddenly get colder than the water below it. What do you think happens to this water?Use the word “density” to explain why this happens.

Conclusion - Conclusion -

Conclusion - Conclusion -

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Check & Learn

Check your understanding of density by answering the questions.

Have your teacher check your answers before you move to another station.



1. The density of an object is a) The mass divided by the volume D = m/v b) The

volume divided by the mass D = v/m c) The same as its weight d) The same as the size of

the object

The density of an object is…a) The mass divided by the volume

D = m/v b) The volume divided by the mass

D = v/m c) The same as its weight d) The same as the size of the

object

If two objects have the same volume but one has a greater mass, the one with greater mass… a) Has a lower density b) Has a higher density c) Will float d) Will sink

If two objects have the same mass but different volumes a) The one with the larger volume

has the lower density b) They must have the same

density c) The one with the larger volume

has the higher density d) The one with the larger volume

is twice as dense

Density is a characteristic property of a substance. This means that the density of water…a) Changes depending on the volume b) Stays the same regardless of the volume c) Is greater for a greater mass of water d) Is less for a smaller mass of water

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1. The density of an object is a) The mass divided by the volume D = m/v b) The

volume divided by the mass D = v/m c) The same as its weight d) The same as the size of

the object

An object should float in a liquid if it is… a) More dense than the liquid b) Less dense than the liquid c) Lighter than metal d) Shaped like a ball

A tiny piece of sand is very light but sinks in water. This is because… a) Sand is a solid b) Sand is less dense than waterc) There is more water than sand d) Sand is more dense than water

Wood floats in water. If you measured the mass of the same volume of wood and water… a) The water would have a greater

mass b) The water would have a lower

mass c) The mass of the wood and

water would be the same d) The mass of the wood and

water would both be 100 grams

a) The molecules in hot water move slower and are slightly closer together

b) The molecules in hot water are larger c) The molecules in hot water move faster

and are slightly further apart d) The molecules in cold water move faster

and are further apart

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3 4The density of hot and cold water are different mainly because…

Draw & Learn

Draw & label a diagram to illustrate density.Make sure to include:• Mass• Volume• Particles


Explore & Learn Some More

1. Drop a ball of clay into the water.

2. Form the clay into a shape that allows it to float.

Answer the questions on the task cards.

Make sure your answers in the correct spot.


What happened when you dropped the ball of clay in the

water?

Is the clay more or less dense than water? How do you know?

Sketch the shape you made from the ball of clay.

What happened to this shape in the water?

Explain what has to happen for the clay to

float on water.

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