Flame Tests Chemistry Lab for High School | Flame Test Experiment Guide

Flame tests are a classic high school chemistry lab that allow students to identify metal ions based on characteristic flame colors. In this flame test chemistry lab, students observe how different elements emit distinct colors when heated, helping them connect atomic structure, electron energy levels, and atomic emission to real laboratory observations. This flame test experiment is easy to set up, highly visual, and consistently engaging for high school chemistry students, making it an ideal lab for teaching electron configurations, periodic trends, and the behavior of excited electrons.

This flame test lab is an absolute favorite of mine and a much loved lab by all of my students. The best time to use this lab is when teaching atomic structure, electron configurations, energy levels, ground state, and excited state.  

TLDR? Go straight to my TPT store to view this flame test lab.

What is the purpose of a flame test?

A flame test is used to detect the presence of certain metal ions. The test involves heating a sample of the element and observing the resulting color of the flame. When atoms of elements are heated to high temperatures, some electrons may absorb enough energy to allow them to move to higher energy levels. The element is then said to be in the "excited state." This excited atom is unstable, and the electrons quickly return back to their positions of lower energy or their ground state. As the electrons return to their ground state, the energy that was absorbed is given off in the form of visible light. The color of this light can be used to identify the elements involved. In a flame test, the element will give off a characteristic color that serves as a simple method of identification of that element.   

Purpose of the Lab:

• To observe the characteristic colors produced by metallic ions when heated in a flame.
• To identify an unknown metallic ion by means of its flame test.
• To identify the components of a mixture using cobalt glass.

Required Materials:

Bunsen burner, Lab apron, Wood Splints, Safety goggles, Unknown solutions, Test Tubes, Cobalt glass squares, Test Tube Racks, Nitrate solutions of sodium, potassium, lithium, calcium, strontium, barium, and copper.

Step By Step Procedures, Tips, and Suggestions

• I like to set up different lab stations and have the students rotate through the stations. I set up stations for the 7 different metal ions that I will have the students test. Students are required to rotate through these 7 stations first. The standard flame test procedure helps students identify metal ions based on characteristic flame colors.
• After the students have identified the colors of the above 7 metal ions, I assign an unknown for them to identify.  
• Finally, I have the students use cobalt glass to identify the components of a mixture.

• I have used metal inoculating loops as a means of heating the metal ion sample, but I prefer to use wood splints. They are cheap and disposable. Be sure to soak them in the metal nitrate solutions prior to the start of the lab. 

I set up individual lab stations for each metal ion and have students rotate through the stations. 

In a flame test, the element will give off a characteristic color.  It is difficult to catch on camera, but the photos in this post show the characteristic colors of barium (lime green) and lithium (crimson).

 

After students have observed all colors, I assign them an unknown element to identify. 

Using cobalt glass, students determine the identity of elements in a mixture. 
When viewing the flame test with the naked eye, the student will see the yellow color of sodium.
When viewing the flame test while looking through the cobalt glass the student will see the violet color of potassium.

To me this lab serves a greater purpose than just learning to identify metal ions from their flame tests. This lab gets my students so excited about chemistry.... and that excitement makes all the difference in the world when trying to teach chemistry to high school students.

This lab is in my TpT store and can be viewed at this link.

Flame Test Lab FAQs

What is the purpose of the flame test lab?
The purpose of the flame test lab is to help students identify metal ions based on the characteristic colors they produce when heated in a flame. This lab reinforces the concept of electron excitation and emission while giving students hands-on experience with atomic structure and spectroscopy concepts commonly taught in high school chemistry.

Why is cobalt glass used in a flame test?
Cobalt glass is used in a flame test to filter out the intense yellow light produced by sodium ions. Because sodium is commonly present as a contaminant, its bright emission can mask other flame colors. Looking through cobalt glass helps students more clearly observe the true flame colors of other metal ions.

Other Chemistry Labs Your Students Might Enjoy

If you're looking for additional hands-on chemistry labs for your students, you might also enjoy this percent composition lab, where students use experimental data to determine the composition of a compound.

Another engaging activity students enjoy is this mole concept chemistry lab, which helps students visualize and understand the mole through hands-on investigation.

Students can also explore chemical formulas experimentally in this composition of a hydrate lab, where they determine the water content of a compound using real laboratory data.

Have Fun Teaching!

Chemistry Mole Lab Activity: How Big Is a Mole?

The mole concept is one of the most important topics in a chemistry course, but it is also one of the most difficult for students to truly understand.

Students can memorize definitions and formulas, yet many still struggle to visualize the size of a mole or understand how mole conversions connect mass, atoms, and molecules. Because of this, students benefit from hands-on activities that allow them to measure substances and perform real calculations.

One activity that works particularly well is a simple lab where students determine how many moles are present in a teaspoon of common substances. This chemistry mole lab activity is designed for high school students and gives teachers a simple way to introduce the mole concept using hands-on learning.

This lab is quick to set up, uses inexpensive materials, and gives students meaningful practice converting between mass, moles, and molecules.

Simple Materials for This Mole Lab

One of the things I love most about this activity is how easy it is to prepare. The materials are simple and inexpensive, and most chemistry classrooms already have everything needed.

Materials include:

• Balance
• Weighing dishes
• Plastic spoons
• Water
• Salt (NaCl)
• Sugar (C₁₂H₂₂O₁₁)
• Chalk
• Chalkboard

Because the materials are so simple, this lab works well as:

• An introduction to the mole concept
• A practice activity during a mole unit
• A review before moving into stoichiometry

Teachers can quickly set up stations by placing the materials at lab tables and distributing the student lab pages.

What Students Do in the Activity

Students begin by determining the mass of one teaspoon of a substance such as water, salt, or sugar.

After measuring the mass, students perform a series of calculations to determine:

• The number of moles in the sample
• The number of molecules present
• The number of atoms of a specific element within the compound

This process gives students repeated practice converting between:

mass → moles → molecules

Because students are working with real measurements rather than abstract numbers, they begin to develop a much better sense of how chemists use the mole as a counting unit.

Student Designed Investigation

The second part of the activity adds an inquiry component.

Students design their own simple experiment to determine how many moles of chalk are required to write their name on the chalkboard.

Students must:

• Describe their experimental procedure
• Construct a data table
• Collect measurements
• Convert their data into moles

This portion of the lab gives students additional practice with:

• The scientific method
• Experimental design
• Mole conversions

Students also enjoy comparing the size of their names and discussing their results with classmates.

Why This Lab Works Well in the Classroom

Many students struggle with the mole concept because it feels abstract and disconnected from real substances.

This activity helps students see how mole calculations relate to actual measurements. By working with familiar materials such as water, salt, and sugar, students begin to understand how chemists connect mass and the number of particles in a sample.

The lab also works well because it combines:

• Hands-on measurement
• Calculation practice
• Student-designed investigation

Together, these elements reinforce the mole concept in a way that lectures and worksheets alone often cannot.

Use This Mole Concept Lab in Your Classroom

If you would like to use this activity with your students, you can find the complete lab here.

The resource includes:

• Student lab pages
• A complete teacher guide
• Answer key
• Instructions for the student-designed chalk investigation

This activity works well for Physical Science or Chemistry students in grades 9-12 and is easy to set up for classroom use.

More Chemistry Labs for Your Classroom

If you are looking for additional chemistry labs, you may also enjoy reading about these activities:

Percent Composition Lab

Flame Tests Chemistry Lab

For another activity that helps students understand the mole concept, be sure to read:

Making the Mole Concept Click and Stick Lab

Final Thoughts

The mole is one of the foundational ideas in chemistry, but students often need multiple experiences working with real substances before the concept truly clicks.

This simple lab provides students with an opportunity to measure, calculate, and apply mole conversions in a meaningful way. With inexpensive materials and minimal preparation, it is an easy activity to add to any mole unit.

Informational Text Reading with Graphic Organizers

Here's a great new free item for your science classroom:  

DNA Informational Text Reading with Graphic Organizers

I teach in a Common Core state, and in a school that is really pushing the implementation of the Common Core State Standards.  We have to show evidence of this implementation in our classroom.  I obviously have to do what is required of me by my admin, but at the same time, I do not want to lose valuable classroom teaching time and get behind on the vast amount of course content that I am also required to teach.

I recently developed this lesson for my students.  In our unit on DNA, RNA, and Protein Synthesis, I love to tell the history of Watson and Crick and their discovery of the structure of the DNA molecule.  In 1953, James Watson and Francis Crick rocked the scientific world with their discovery, and with the publication of their one-page paper in Science magazine describing the DNA molecule.  This one-page paper is a marvelous bit of history, and it is a fascinating read.  It is also a perfect piece of informational text that can be used to teach the Common Core State Standards.

The one-page article can be printed and used in your science classroom.  I developed a 4-page set of graphic organizers to go along with this article.  As students read the article they are required to complete the graphic organizers. You can have your students complete all four organizers (I usually do!) or each graphic organizer can be used alone. The printable lesson is perfect for traditional classroom settings, and the paperless, digital Google Apps version is perfect for distance learning and 1:1 classrooms.

You can, of course, use class time for this activity, but I usually assign this as a homework assignment.  I assign this at the beginning of my unit on DNA, and usually give a week to complete the assignment. The article and the graphic organizers provide great review on the topics I am teaching in class, as well as a lesson in the reading of informational text.  It's a win-win!  (Pssst...This is also a great activity to leave in your sub folder in the event of your unexpected absence from school!)

Here is a look at each of the graphic organizers:

(They look best if printed in color, but print perfectly fine in grayscale.)

This is a free download, and will always remain a free download.  Enjoy!

Related products include:

DNA, RNA, and Protein Synthesis Complete Unit Plan Bundle

Genetics Complete Unit Plan Bundle

FREE DNA Extraction Lab

Composition of a Hydrate Lab Activity: Percent Water and Formula

A composition of a hydrate lab is a classic high school chemistry activity in which students determine the percent of water in a hydrate and use mass data to calculate the formula of a hydrate. This hands-on lab gives students meaningful practice with water of hydration, anhydrous salts, percent composition, and chemical formulas while working with real experimental data.

If you are looking for a ready to use composition of a hydrate lab for your chemistry classroom, this resource includes printable and editable student handouts, a teacher guide, sample calculations, and an answer key. It is one of my favorite chemistry labs because it has a simple materials list, it is easy to set up and clean up, and it gives students a clear application of chemical formulas and percent water calculations.

What Is a Hydrate in Chemistry?

Hydrates are ionic compounds that contain a specific number of water molecules as part of their structure. That water is called the water of hydration, and it is present in a definite ratio. When the hydrate is heated, the water is released as water vapor and the remaining solid is called the anhydrous salt.

This makes hydrates a great topic for chemistry lab work because students can observe a visible change, measure mass before and after heating, and use those measurements to determine both the percent of water in the hydrate and the correct chemical formula.

What Is the Composition of a Hydrate Lab?

In this hydrate lab, students heat a known mass of copper (II) sulfate hydrate in an evaporating dish to remove the water of hydration. They then measure the mass of the anhydrous salt that remains. The difference between the initial mass and the final mass is the mass of water lost during heating.

In our lab, we used copper (II) sulfate pentahydrate. A fine crystal works best for this activity. Since we only had medium crystals available, my students used a mortar and pestle to grind the copper sulfate into a finer powder before heating.

Students love seeing the visible change as the blue hydrate becomes a much lighter anhydrous solid. That observation makes the chemistry more concrete and helps them connect the lab results to the structure of the compound.

How to Calculate the Percent of Water in a Hydrate

One reason this chemistry lab works so well is that students are using real mass data to calculate the percent of water in a hydrate. First, they find the mass of the hydrate sample before heating. Then, after heating removes the water of hydration, they find the mass of the anhydrous salt. The difference between those two values is the mass of water lost.

From there, students calculate the percentage of water in the hydrate by comparing the mass of water lost to the original mass of the hydrate sample. This gives students valuable practice with percent composition in a meaningful lab setting rather than just in isolated textbook problems.

If your students need more practice with percent composition, take a look at this post on my percent composition chemistry lab. It is another great way to reinforce percent calculations with experimental data.

How to Determine the Formula of a Hydrate

After finding the mass of water lost, students can use their data to determine the formula of the hydrate. In this lab, students use the mass of the remaining copper (II) sulfate and the mass of the water released during heating to calculate the mole ratio between salt and water. That ratio leads them to the correct hydrate formula.

This part of the lab is especially valuable because students move beyond simple observation and into chemical reasoning. They are not just watching a color change. They are using evidence to determine that the compound is copper (II) sulfate pentahydrate.

Determining the formula of a hydrate also connects nicely to mole concepts. If your students need more support with that idea, this blog post on my mole lab activity is a great related chemistry resource to use after your chemical formulas unit.

What This Looks Like in Your Classroom

This lab is a strong fit for a chemical formulas unit because it gives students a clear purpose for the math they are doing. Students heat the hydrate, collect mass data, calculate the percentage of water, and determine the correct formula of the compound. The activity is straightforward, the materials are manageable, and the students get strong results.

I also love that this lab gives students practice comparing experimental data to theoretical results. That is such an important science skill, and it gives you a great opportunity to talk about sources of error and percent error in the lab.

The resource includes editable student handouts in two formats, along with a teacher guide, sample data, worked calculations, and answers to the analysis questions. That makes it easy to fit the lab to your own students and your own classroom routines.

If you want a ready to use version for your classroom, you can find the full Composition of a Hydrate Lab here.

More Chemistry Labs for Your Classroom

If you are teaching chemistry this time of year, you may also like to read blog posts about these chemistry lab activities:

• Percent Composition Chemistry Lab
• Chemistry Lab: How Big Is a Mole?
• Composition of a Hydrate Lab on TpT

How much Vitamin C is in your fruit juice?

Lab: Determining the Amount of Vitamin C in Fruit Juices

I  have been doing this lab every year for a long, long time.  I always enjoy it, and so do my students. I often do this lab with my biology students when teaching about nutrition and digestion, but my favorite use of this lab is with my chemistry classes.  This lab is perfect to introduce the idea of titrations, equivalents, and as a review of dimensional analysis.

In this experiment the student will use a lab procedure known as a titration to determine the amount of Vitamin C found in a 6 ounce serving of various fruit juices.  I most often use orange juice, pineapple juice, and apple juice. 

A titration is the controlled addition and measurement of the amount of a solution of known concentration required to react completely with a measured amount of a solution of unknown concentration.  Titration provides a means of determining the chemically equivalent amounts of two substances.  

The materials list is short and consists of items found in almost all labs..... no fancy equipment required!  You will need:  Spot plate, Thin stemmed or microtip Beral pipets  (or medicine droppers),  White paper for background, Ascorbic acid standard solution,  Apple juice,  Orange juice,  Pineapple juice, Starch solution,  Iodine solution and Plastic Toothpick (stirrer).

In order to determine the amount of Vitamin C in the fruit juice, the student must first do a titration using a vitamin C (ascorbic acid) solution of known concentration.  An iodine/starch complex is used so that a color change can be detected.  The number of drops of iodine added will be used to determine the amount of Vitamin C present in the juice.  

When ascorbic acid (Vitamin C) comes into contact with iodine, it is oxidized to form dehydroascorbic acid.  When Vitamin C and iodine are in solution together, they will form iodide.  As iodine is added during the titration, iodide will continue to be formed until there is no more Vitamin C left in the solution.  At this point, iodine becomes present in the solution and the starch turns a blue-black color.  The starch is used as an indicator because it turns black in the presence of iodine, but not for iodide.  The amount of iodine that is added during the titration can be used to indicate the amount of Vitamin C present in the fruit juice.

Set up for the lab is quick and easy, and does not take a lot of advance preparation.  

This lab is available in my TpT store and can be viewed here:  Determining the Amount of Vitamin C in Fruit Juices.