How To Measure Water In A Graduated Cylinder

Are you loving this? Not loving this? Please consider taking a moment to share your feedback with us. Cheers!

Lesson 3.two

Finding Volume: The Water Displacement Method

Cardinal Concepts

A submerged object displaces a volume of liquid equal to the volume of the object.
I milliliter (i mL) of water has a book of 1 cubic centimeter (1cm³).
Different atoms have different sizes and masses.
Atoms on the periodic table are arranged in order co-ordinate to the number of protons in the nucleus.
Fifty-fifty though an cantlet may be smaller than another atom, it might have more mass.
The mass of atoms, their size, and how they are arranged determine the density of a substance.
Density equals the mass of the object divided by its volume; D = k/five.
Objects with the aforementioned mass but different book take different densities.

Summary

Students use the water displacement method to notice the book of different rods that all have the same mass. They calculate the density of each rod, and use the feature density of each material to identify all five rods. Then students consider the relationship between the mass, size, and arrangement of atoms to explain why different rods have unlike densities. Students volition be briefly introduced to the periodic table.

Objective

Students will be able to explain that materials have feature densities because of the different mass, size, and system of their atoms. Students will be able to use the volume deportation method to find the volume of an object.

Evaluation

Download the student activity sheet, and distribute one per student when specified in the activity. The activeness canvas will serve every bit the "Evaluate" component of each 5-E lesson program.

Prophylactic

Make sure you and your students wear properly plumbing equipment goggles.

Materials for Each Group

Set of 5 different rods that all have the same mass
Graduated cylinder, 100 mL
Water in a cup
Figurer

Notes about the materials:

For this lesson you volition need a set of five solid rods, each with the same mass, same diameter, but a different volume. Each rod is fabricated of a different cloth. There are several versions of these rods available from different suppliers. This activity uses the Equal Mass Kit from Flinn Scientific (Product #AP4636) but can be adapted to any set of equal mass rods. Since there are simply five samples in the Equal Mass kit, you lot may need two kits so that each grouping can piece of work with a sample.

This chart volition assist yous place each rod. Exercise non reveal this data to the students. They will discover the identity of each rod and the changed relationship between the density and the length of each rod later in this lesson.

Tabular array 1. Concrete properties for solid cylinder unkowns.
Sample	Material	Estimate Density (1000/cm³)	Relative length
Smallest metallic	Brass	7.5	shortest
Shiny gray metallic	Aluminum	three.0
Nighttime gray	PVC	one.4
Alpine off-white	Nylon	one.1
Tallest white	Polyethylene	0.94	longest

Show students 5 rods that have the aforementioned mass only dissimilar volumes.

Show students the v rods and explain that they all take the aforementioned mass. Then agree up the longest, eye-sized, and shortest rods and remind students that they have the same mass.

Ask students to make a prediction:
- Which rod is the most dumbo? To the lowest degree dense? In betwixt?
Students may reason that since the mass of each rod is the same, the book of each rod must have something to do with its density. Some may go and so far as to say that the rod with the smallest volume must accept the highest density, because the aforementioned mass is packed into the smallest volume. Or that the rod with the largest volume must accept the lowest density, because the aforementioned mass is spread out over the largest volume.

Tell students that like the cubes in the previous activity, they will need to know the volume and mass of each of the samples. They will also calculate the density of each sample and use this value to figure out which fabric each rod is made of.
Testify an blitheness and demonstrate how to measure volume using the water displacement method.

Project the animation Water Displacement.

Play the blitheness every bit you demonstrate the water displacement method using a loving cup of h2o, a graduated cylinder, and a rod, the way students volition exercise in the activity. Use the dark gray plastic sample and so that students can see information technology better.

Book
1. Demonstrate what students will exercise by pouring water from a cup into a 100-mL graduated cylinder until it reaches a height that will encompass the sample. This is the "initial water level."
2. Tell students that the surface of h2o in a tube may non be completely flat. Instead, the surface may curve in a shallow U-shape called the meniscus. When measuring, read the line just at the bottom of the meniscus.
3. Tilt the graduated cylinder and slowly slide the sample into the water. Hold the graduated cylinder upright. Record the level of the water. Indicate out that this is the "last water level."
4. Tell students that you want to find out how much the water level changed. Decrease the initial h2o level from the terminal water level to discover the volume of the rod.
5. Volume of sample = final water level − initial water level.
6. Students may exist confused that the unit of measurement for book in the graduated cylinder is milliliters (mL), when in the previous lesson students calculated book in cubic centimeters (cm^three). Explain to students that 1 ml is the same as 1 cm³. Click on the oval-shaped push on the first screen of the animation marked "1 mL = 1 cmⁱⁱⁱ."
Ask students:

When you identify a sample in the water, why does the water level go upward?

The volume that the rod takes upwards pushes or displaces the water. The only place for the water to go is up. The amount or volume of water displaced is equal to the book of the sample.

Is the volume of the sample equal to the final water level?

No. Students should realize that the volume of the rod is not equal to the level of the water in the graduated cylinder. Instead, the volume of the rod equals the amount that the water went upwardly in the graduated cylinder (the amount displaced). To observe the amount of h2o displaced, students should subtract the initial level of the h2o (threescore mL) from the terminal level of the h2o.

What units should y'all use when you record the volume of the sample?

Because they will exist using the volume to summate density, students should tape the book of the sample in cm³.

Mass

Student groups volition not need to measure the mass of the rods. The mass of each rod is the aforementioned, 15 grams, and is given in their chart on the activity sheet. They volition demand to mensurate the volume of each of the five different rods and summate their densities. Students will use their values for density to identify each rod.

Density

Demonstrate how to calculate density (D = one thousand/5) by dividing the mass by the book. Point out that that the answer will be in grams per cubic centimeter (m/cm³).

Give one activity sail to each student.

Students will record their observations and answer questions nearly the activity on the action sheet. The Explain It with Atoms and Molecules and Accept It Farther sections of the activity sheet will either exist completed every bit a form, in groups, or individually, depending on your instructions. Expect at the teacher version of the activity canvass to discover the questions and answers.

Give students time to answer questions i–5 on the activity sail before starting the activeness.

Take students calculate the density of v different rods and use the characteristic property of density to correctly identify them.

Note: The densities for the iii plastics are similar, and so students need to be very careful when measuring their book using the water displacement method. Also, information technology is difficult to measure the volume of the smallest rod. Give students a hint that information technology is betwixt i.5 and 2.0 mL.

Question to investigate

Can you apply density to identify all five rods?

Materials for each group

Set of five different rods that all accept the same mass
Graduated cylinder, 100 mL
Water in a cup
Calculator

Teacher preparation

Use a permanent marker to mark the five rods with letters A, B, C, D, and E. Keep rails of which letter of the alphabet corresponds to which sample without letting students know. If y'all are using two or more sets of rods, be sure to mark each sample of the same cloth with the same alphabetic character.
Afterward a group finds the volume of a sample, they should then laissez passer that sample to another group until all groups have found the volume of all five rods.
For the longest sample, which floats, students can use a pencil to gently push button the sample only beneath the surface of the water to measure out its full book.

Process

Volume
1. Pour enough h2o from your loving cup into the graduated cylinder to reach a height that will cover the sample. Read and tape the book.
2. Slightly tilt the graduated cylinder and carefully place the sample into the h2o.
3. Place the graduated cylinder upright on the table and look at the level of the water. If the sample floats, use a pencil to gently push the peak of the sample merely nether the surface of the water. Tape the number of milliliters for this final water level.
4. Find the amount of water displaced by subtracting the initial level of the water from the final level. This volume equals the volume of the cylinder in cmⁱⁱⁱ.
5. Record this volume in the nautical chart on the activity canvas.
6. Remove the sample by pouring the water back into your cup and taking the sample out of your graduated cylinder.

Density

Summate the density using the formula D = chiliad/v. Record the density in (grand/cm^three).

Trade samples with other groups until you have measured the volume and calculated the density of all v samples.

Table 2. Book, mass, and density for unknowns A–H
Sample	Initial water level (mL)	Final water level (mL)	Volume of the rods (cm³)	Mass (g)	Density (g/cm³)
A				15.0
B				15.0
C				15.0
D				15.0
E				xv.0

Identify the samples
1. Compare the values for density you calculated to the values in the chart. So write the letter name for each sample in the chart.

Note: The densities students calculate may not be exactly the aforementioned equally the given densities in the chart. Equally students are working, bank check their values for book to exist certain that they are using the difference betwixt the last and initial water levels, not only the final level.

Table 3. Volume, mass, and density for unknowns A–H
Material	Estimate density (g/cm³)	Sample (Messages A–East)
Brass	8.8
Aluminum	2.vii
PVC	one.four
Nylon	1.2
Polyethylene	0.94

Discuss whether students' values for density support their predictions from the beginning of the lesson.

Hash out student values for density for each of the samples. Point out that unlike groups may take different values for density, just that near of the values are shut to the values in the chart.

Ask students:

Each group measured the book of the same samples. What are some reasons that groups might have different values for density?

Students should realize that minor inaccuracies in measuring volume can business relationship for differences in density values. Another reason is that the graduated cylinder, itself, is not perfect. So in that location is ever some uncertainty in measuring.

Remind students that in the beginning of the lesson they made a prediction about the density of the small, medium, and long sample. Students should have predicted that the longest cylinder has the everyman density, the shortest cylinder has the highest density, and the centre is somewhere in between.

Ask students:

Was your prediction nearly the density of these three samples correct?

Have students look at their chart with the values for mass, book, and density for each cylinder. Have them look for a relationship betwixt the book and the density. Students should realize that the shortest cylinder has the greatest density and the longest cylinder has the lowest density.

Is information technology fair to say that if two samples have the same mass that the one with the larger volume will accept a lower density?

Aye.

Why?

Considering the samples have the same mass, their volumes will requite you an idea nearly their densities according to the equation D = g/v. If a larger number for volume is in the denominator, the density volition be lower.

Is information technology off-white to say that the one with the smaller book volition have a higher density?

Aye.

Why?

If a smaller number for volume is in the denominator, the density volition exist higher.
Have students look at the size and mass of atoms to assistance explain why each sample has a different density.

Projection the epitome Atomic Size and Mass.

Tell students that this chart is based on the periodic table of the elements just that it only includes the kickoff 20 elements out of about 100. A representation of an atom for each element is shown. For each element, the diminutive number is higher up the atom and the diminutive mass is below. This nautical chart is special because it shows both the size and mass of atoms compared to other atoms.

Note: Students may want to know more nigh why atoms have different diminutive numbers and different sizes. These questions volition be covered in after chapters but you can tell them that the atomic number is the number of protons in the center or nucleus of the atom. Each element has a sure number of protons in its atoms, so each element has a different diminutive number. The deviation in size is a little harder to explain. Atoms accept positively charged protons in the nucleus and negatively charged electrons moving around the nucleus. It'due south actually the space the electrons occupy that makes up most of the size of the atom. Every bit the number of protons in the atom increases, both its mass and the strength of its positive charge increases. This extra positive charge pulls electrons closer to the nucleus, making the cantlet smaller. The atoms go bigger again in the adjacent row because more than electrons are added in a space (free energy level) further from the nucleus.

Allow students know that they will larn more about the periodic table and atoms in Chapter 4. For now, all students need to focus on is the size and mass of the atoms.

Tell students that the deviation in density between the pocket-sized, medium, and large samples that they measured tin can be explained based on the atoms and molecules they are made from.

Projection the image Polyethylene (longest rod).

Polyethylene is made of long molecules of only carbon and hydrogen atoms. In the Atomic Size and Mass chart, the mass of carbon is pretty low, and the mass of hydrogen is the lowest of all the atoms. These low masses help explain why polyethylene has a low density. Another reason is that these long, skinny molecules are loosely packed together.

Project the prototype Polyvinyl Chloride (medium-length rod).

Polyvinyl chloride is made up of carbon, hydrogen, and chlorine atoms. If yous compare polyvinyl chloride to polyethylene, you will find that there are chlorine atoms in some places where there are hydrogen atoms in the polyethylene. In the nautical chart, chlorine has a large mass for its size. This helps make polyvinyl chloride more dense than polyethylene. The density of unlike plastics is commonly caused by the unlike atoms that can be connected to the carbon—hydrogen bondage. If they are heavy atoms for their size, the plastic tends to exist more dumbo; if they are lite for their size, the plastic tends to be less dense.

Project the prototype Brass (shortest rod).

Brass is a combination of copper and zinc atoms. Copper and zinc come up later in the periodic table, so they are not shown in the chart, but they are both heavy for their size. The atoms are besides packed very closely together. For these reasons, contumely is more dense than either polyethylene or polyvinyl chloride.
Discuss the density of calcium compared to the density of sulfur.

Have students refer to the illustration of calcium and sulfur on their action sheets. Explain that a calcium atom is both bigger and heavier than a sulfur atom. Only a piece of solid sulfur is more dense than a solid piece of calcium. The density of sulfur is nigh 2 g/cm³ and the density of calcium is most 1.v k/cmⁱⁱⁱ.

Ask students:

Based on what you lot know almost the size, mass, and arrangement of atoms, explicate why a sample of sulfur is more than dense than a sample of calcium.

Even though a sulfur atom has less mass than a calcium cantlet, many more than sulfur atoms can pack together in a certain corporeality of space. This gives sulfur more than mass per volume than calcium, making information technology more dense.