Topicm80c947a662a6a303_1528449000663_0Topic

Determining the density of solids with the scales and the ruler

Levelm80c947a662a6a303_1528449084556_0Level

Second

Core curriculumm80c947a662a6a303_1528449076687_0Core curriculum

I. Using physical terms and quantities to describe phenomena and to identify their examples in everyday life.

Timingm80c947a662a6a303_1528449068082_0Timing

45 minutes

General learning objectivesm80c947a662a6a303_1528449523725_0General learning objectives

Experimental determination of density of bodies with a regular shape.

Key competencesm80c947a662a6a303_1528449552113_0Key competences

1. Determining the intermediate quantities required to determine the density.

2. Using the formula for body density.

Operational (detailed) goalsm80c947a662a6a303_1528450430307_0Operational (detailed) goals

The student:

- makes the measurements necessary to determine the density of the body,

- determines experimentally the density of bodies with a regular shape.

Methodsm80c947a662a6a303_1528449534267_0Methods

1. Learning through observation.

2. Applying the obtained results in new practical or theoretical tasks.

Forms of workm80c947a662a6a303_1528449514617_0Forms of work

1. Individual work.

2. Performing experiments in groups.

Lesson stages

Introductionm80c947a662a6a303_1528450127855_0Introduction

Task

Answer the questions:

1. What is the measure of the quantity of matter?

2. Give a definition of the volume which the body occupies.

3. Provide the pattern and the unit of density of bodies.

4. Does the density of the body depend on its state of matter?

Answer:

1. The body mass is the measure of the quantity of matter.

2. Body volume is the space occupied by all atoms of this body.

3. Density of the physical body - d is determined with the formula:
$d=\frac{m}{V}$
where:
m – is the mass of the tested physical body,
V – is the volume of the tested body.
The unit of density in the SI system is $\frac{kg}{m^3}$.

4. The density of bodies depends on the their state of matter. The density of solids and liquids is similar and ranges from 900 $\frac{kg}{m^3}$ to 19320 $\frac{kg}{m^3}$ for gold. The density of gases is much lower and ranges from 0,09 $\frac{kg}{m^3}$ for hydrogen to 5,9 $\frac{kg}{m^3}$ for xenon.

Procedurem80c947a662a6a303_1528446435040_0Procedure

Task
Do experiment in groups.
Familiarize yourself with the instructions for the experiment.

Group I
Experiment

Research problem:
Determining the density of bodies with regular shapes.

Research hypothesis:
To determine the density of bodies with regular shapes, it is sufficient to measure the body mass and measure its linear dimensions.

You will need:
- rubber ball,
- scales,
- caliper.

Instruction:
1. Determine the mass of the ball with the scale.
2. Determine the diameter (D) of the ball using the caliper.
3. Calculate the volume of the ball using the following formula:

where:
V - is the ball volume [cmIndeks górny 3³],
$\mathrm{\pi }$ – the constant which equals to 3,14,
r - the radius of the ball equals to $\frac{D}{2}$ [cm].
4. Calculate the density of the material which the ball is made of.
5. Compare the result you received with the value of material density from the density table.

Prompt:
The density of the gum ranges from 1.1 to 2 $\frac{g}{c{m}^3}$.m80c947a662a6a303_1527752263647_0Prompt:
The density of the gum ranges from 1.1 to 2 $\frac{g}{c{m}^3}$.

Conclusion:
Determining the volume of the body with a regular shape in the form of a ball requires only measuring the diameter of the ball. Using the formula for the volume of the ball makes it easier to determine the actual volume of the ball, without having to dip it into water.m80c947a662a6a303_1527752256679_0Conclusion:
Determining the volume of the body with a regular shape in the form of a ball requires only measuring the diameter of the ball. Using the formula for the volume of the ball makes it easier to determine the actual volume of the ball, without having to dip it into water.

Group II
Experiment

Research problem:
Determining water density.

Research hypothesis:
Liquid takes the shape of the container in which it is located. This property can be used to determine the density of liquids.

The following equipment will be required:
- glass,
- scales,
- caliper,
- water.

Instruction:
1. Determine the mass of water using the scales.
- Weigh the glass with the mass mIndeks dolny s_s =
- Weigh the glass with water, write its mass mIndeks dolny s,w_s,w =
- Calculate the mass of water mIndeks dolny w_w = mIndeks dolny s,w_s,w - mIndeks dolny s_s
2. Determine the diameter of the glass (D) using the caliper.
3. Determine the height of water column h =
4. Calculate the volume of water using the formula for the volume of the cylinder:

where:
V - is the volume of the cylinder [cmIndeks górny 3³],
$\mathrm{\pi }$ – is the constant which equals 3,14,
r - is the radius of the cylinder base and equals $\frac{D}{2}$ [cm].
5. Calculate the density of water.
6. Compare the result you obtained with the value of the material density from the density table.

Conclusion:
Determining the volume of the body with a regular shape in the form of a cylinder requires only measuring the diameter of the base of the cylinder and its height. The usage of the formula for the cylinder volume makes it easier to determine the actual volume of the cylinder. Taking into the consideration the fact that water takes the shape of the container makes it easier to calculate its actual volume.

Task
Suggest a description of the experiment in which you can determine the density of air. Add some information about the topic, the equipment and the instructions.m80c947a662a6a303_1527712094602_0Suggest a description of the experiment in which you can determine the density of air. Add some information about the topic, the equipment and the instructions.

Task
Decide if the sentences below are true or false and select all the correct answers.
a) The diameter of the cylinder can be measured using the caliper.
b) The diameter of the ball can be accurately measured using the caliper.
c) The diameter of the ball can be easily measured with the ruler.
d) The volume of a straight cylinder is calculated with the formula:

where:
V - is the volume of the cylinder [cmIndeks górny 3³],
$\mathrm{\pi }$ – is the constant which equals 3,14,
r - is the radius of the cylinder base which equals $\frac{D}{2}$ [cm].

Answer:
a) True.
b) True.
c) False.
d) True.

[Interactive illustration]

Lesson summarym80c947a662a6a303_1528450119332_0Lesson summary

The density of the body with regular shapes requires measuring its mass and its dimensions. On their basis the body volume can be determined using the calculation method. The density is determined with the density formula:

Selected words and expressions used in the lesson plan

calipercalipercaliper

cylindercylindercylinder

densitydensitydensity

diameterdiameterdiameter

massmassmass

radiusradiusradius

regular shaperegular shaperegular shape

spherespheresphere

sufficientsufficientsufficient

volumevolumevolume