Name: ______________________ The Beekman School

Date: ______________________ Chemistry: PHET Lab - Calorimetry

Introduction:

In class we have been discussing the topics of heat and temperature, and how they’re related.
We have learned how heat is energy, how temperature is a measure of that energy in an object,
and how different materials transfer heat differently. Today, we are going to perform a lab that
explores those different concepts and mimics an experiment that has been performed in
chemistry labs all around the globe.

Lab Objectives:

The objective of our experiment is to perform a routine procedure that has been done in every
chemistry lab around the world - finding the specific heat of a given substance. The practice of
determining specific heat for a substance is so old and widely popular that it even has its own
name: Calorimetry. We have already studied in class how we can use the specific heat equation
(Q=mcΔT) to calculate the specific heat, c, of some object given other information about that
object, specifically its mass, m, change in temperature ΔT, and how much heat energy it has
released or absorbed, Q. The goal of this lab is to take accurate measurements of those three
quantities for different objects and substances so we may calculate their specific heat.

PHET - Our Virtual Laboratory

Because our class does not have access to a real

laboratory, we will be using the virtual lab provided
by U. Colorado’s PHET program. This program is
useful as it incorporates foundational chemistry
concepts into its interactive experiments and does
not distract the user with numerical measurements.
This is beneficial for building an intuition around a
concept, but means we will have to modify out
understanding of the program if we want to take the
measurements typically done in a laboratory e
xperiment.

The link to our specific experiment can be found on ThinkWave, but is also here:

https://phet.colorado.edu/en/simulations/energy-forms-and-changes
 To start, we’ll need to label the graduation (tick marks) on our
beakers and thermometer. For our beakers, we will take each
minor tick to mark 10mL of volume, while the major ticks will
mark 50mL [See Fig. 2]. Similarly, on our thermometer, minor
ticks will denote a 25°C change in temperature while the major
ticks will denote a 50°C change in temperature [See Fig. 3].
We will take the lowest available temperature on the
thermometer to be 0°C.

We will also need some information about the objects and

materials we will be working with in order to take indirect
measurements. This information is presented in the data table
below, and when the information is known, it will be present in
the data tables we will use for our experiment.

Object/Substance Density (g/mL) Cube Edge Length (cm)

Water 1 N/A

Oil 0.92 N/A

Iron 7.874 4.072

Brick 1.63 4.072

Finally, we need one last piece of information. In order to heat our

objects/substances, the PHET laboratory offers us a magic bucket
which can act as either a heat source or sink. When the magical
bucket is set to maximum heat, we will assume it is transferring heat
𝐶𝑎𝑙
energy to our object/substance at a rate of 970 𝑆
, or Calories per
second.

With the information above, we should be able to begin our first task: confirming the specific
heat of water.
Objective 1 - Measuring the Specific Heat of Water

The unit of heat measurement we will be using for this lab is the Calorie. By definition of this
𝐶𝑎𝑙
unit, liquid water has the specific heat of 1 𝑔 𝐶 , which is the amount of energy necessary to raise
1 gram of water by 1°C. This definition, while arbitrary, is crucial to our ability to measure the
specific heats of other materials. Because of the importance of this number, we would like to
verify it ourselves. This will also serve as practice in the steps we will need to take to find the
specific heats of other materials, which we might not already know.

To get started, we need to set some things up in the virtual

lab. First, click and drag the beaker of water and place it on
the stand. Then, click and drag the thermometer located in the
top left part of the screen and place it over the beaker of
water:

Slide the blue knob on the bucket up and down and observe
what happens. When the knob is set to heat, you should
notice the temperature reading on the thermometer going up,
indicating the water’s temperature is increasing. Setting the
knob to cool results in the opposite effect: the water’s
temperature decreases. Click the checkbox next to “Energy
Symbols” in the top right of your screen. What do you notice
about the flow of energy?

We are now ready to start taking data. Carefully following the procedure below and fill in the
blanks as necessary. The only external material you will need to perform this experiment is a
timer or stopwatch. You may use your phone for this, or ask the teacher for a time keeping
device.

1) Using the tick marks, determine the volume of water present in the beaker:

Volume: ________________

2) Hold the blue knob on the bucket down to “Cool” until the water is the coolest possible
temperature. Continue to hold the knob on “Cool” until performing step 3.
 3) Simultaneously, start the stopwatch and slide the blue knob up to “Heat”. Hold the blue
knob on “Heat” until the temperature of the water has raised by 100 degrees Celsius.
Once it has, immediately stop your timer and release the blue knob

4) Finally, record the time spent on your timer, Δt:

Δt: ______________

Fill the data you found into the table below. Leave any data you don’t yet know blank:

Table A:
Material Density Volume Mass ΔT (°C) Δt (s) Q (Cal)
(g/mL) (mL) (g)

Water 1

Complete the following problems in order to fill out the rest of the Data Table:

𝑔
1) The density of water is 1 𝑚𝐿
. Given this info and the volume of water listed in the data
table, what is the mass of water present in the beaker, in grams? Write your answer in
the table

2) Given that the beaker of water absorbed 94 calories of heat per second, how much heat
in total did the water absorb while it was being heated? Write your answer in the data
table under Q
Finally, use Q=mcΔT to calculate the specific heat of water, cWater:

cWater = _______________________

Objective 2: Calculating the Specific Heat of Oil

Perform the same initial setup you performed for the water to prepare for beaker of oil for
testing. Play with the beaker of oil in the virtual lab - do you notice anything different about
behavior of the oil compared to the water when the two are heated? Do you notice anything
different when they are being cooled? Write your response below:

We can now repeat the steps we just performed to find the specific heats of other substances.
Repeat the setup and procedure we performed for the beaker of water, except for the beaker of
cooking oil. Use the information gathered to fill out the following data table

Table A:
Material Density Volume Mass ΔT (°C) Δt (s) Q (Cal)
(g/mL) (mL) (g)

Olive Oil 0.92

Finally, use the data table to calculate the specific heat of the oil, cOil :

cOil = _______________________
Objective 3: Calculating the Specific Heat of two Solids

We will now repeat the previous steps to find the specific heats of water and oil, except for solid
materials like iron and brick. Set the iron and brick up on the heating stand in the lab as was
done for the water and oil. Play with the magic bucket’s heating a cooling settings and compare
the behavior of the iron and brick to that of the water and oil. Write your remarks below:

Because iron and brick are solids at room temperature, we cannot measure their volume using
a graduated beaker. Instead, we will use the “fact” that the iron and brick are cubes with
sidelengths of 4.02 cm. Using this fact, calculate the volumes of the iron and brick cubes in cm3
and add it to the table. From there, repeat the steps performed when filling out the prior two data
tables (note: 1cm3 = 1mL)

Table C:
Material Density Edge Length Volume Mass ΔT (°C) Δt (s) Q (Cal)
(g/mL) (cm) (mL) (g)

Iron 7.874 4.02

Table D:
Material Density Edge Length Volume Mass ΔT (°C) Δt (s) Q (Cal)
(g/mL) (cm) (mL) (g)

Brick 1.63 4.02

Calculate the specific heats of iron and brick below:

cIron = ________________

cBrick = _______________
Post Lab Analysis

Complete the following questions after completing the lab and obtaining specific heat values for
water, olive oil, iron, and brick. Please write your answers thoughtfully and using complete
sentences:

1) Because Calorimetry is such a widely common practice in Chemistry, there are many
sources citing their own values for the specific heat of different materials. The table below gives
some officially sources specific heat values:

Material: Water Olive Oil Iron Brick

𝐶𝑎𝑙
Specific Heat ( 𝑔 𝐶 ) 1 0.47 0.106 0.22

Taking these values to be the true, or “actual”, specific heats of our materials, we can assess
how far off our experimentally determined values are. To do this, we calculated the error of our
final value:

𝐸𝑟𝑟𝑜𝑟 = | (𝐴𝑐𝑡𝑢𝑎𝑙 𝑉𝑎𝑙𝑢𝑒)−(𝐸𝑥𝑝𝑒𝑟𝑖𝑚𝑒𝑛𝑡𝑎𝑙 𝑉𝑎𝑙𝑢𝑒) |× 100%

| (𝐴𝑐𝑡𝑢𝑎𝑙 𝑉𝑎𝑙𝑢𝑒) |

Use the formula above to calculate the errors of your 4 specific heat values:

2) Comment on the legitimacy of this experiment. Do you think it would be possible to perform it
in a real lab? What would be the pros and cons of a real lab environment for this experiment?
Explain: