Light and Energy * Flame Test

Light and Energy –
Flame Test
 Objective: SWBAT identify an unknown atom in solution using the
color emitted when heated and complete post-lab questions using
the mathematical relationships between energy, frequency, and
wavelength of light.
 Agenda:
Introduction to visible light emission
Flame Test Pre-lab Questions
Flame Test
Flame Test Post-lab Questions
*Today is the LAST day to turn in late work for this six weeks*
Answer warm-up questions on Pg 24 of your notebook
 What is the relationship wavelength and frequency?
 What is the relationship between frequency and energy?
 What has a shorter wavelength red or yellow light?
 Which has more energy Blue or Yellow?
 Salts are electrically neutral compounds that are composed of
both positively charged ions and negatively charged ions.
 Example:
 Table salt consists of both positive sodium ions (Na+) and negative
chloride ions (Cl–).
Science behind
 Metal salts are used to produce the vivid lights in fireworks!
 The heat from the ignition (flame) causes an influx of energy into
the metal atoms. As heat gets absorbed by the metal atoms,
electrons that are circling around the lower orbitals of the atomic
nucleus excite and jump to a higher energy level.
What causes
light/color to
be released
from metal
 These electrons do not stay in excited states for long - as the heat
dissipates, they soon fall back to their ground states, and give off
the extra energy in the form of light energy.
 Light travels in waves.
Why do we see
different colors
for different
metal ions?
 Different metal atoms produce different colors of light when
excited because the light that they emit is traveling at different
 The wavelengths of light produced by metals vary due to the
amount of energy that is released by the unique arrangement of
electrons in the atom as electrons fall from an excited state back
to a ground state.
 When metal salts emit short wavelengths of visible light in the range
of 400 to 500 nanometers, they produce violet and blue colors.
 When metal salts emit longer wavelengths of visible light in the
range of 600 to 700 nanometers, they produce orange and red colors.
Visible light on
 Yellow and green colors are produced by metal salts that emit visible
light at intermediate wavelengths (500 to 600 nanometers) along
the electromagnetic spectrum.
 Group 1
1. Reed
2. Alexi
3. Ella
4. Jake B.
 Group 2
Lab Groups
(Period 2)
1. Ambika
2. Omar
3. Justin
4. Rachel
 Group 3
1. Sophia
2. Logan
3. Elijah
4. Sheradyn
 Group 4
1. Isaias
2. Andres
3. Leah
4. Jacob
 Group 5
1. Summer
2. Alex R.
3. Ilse
4. Alex H.
 Group 6
1. Josiah
2. Carly
3. Caleb
4. Aaron
 The numbers above represent the role that you will be playing in your
group: *Note all roles must actively participate and positively
contribute to your lab group*
1. Group Facilitator
 Keeps everyone on task and focused
 Ensures everyone knows what goes in the notebook and where it goes
 Leads discussion of pre- and post-lab questions
2. Safety Manager
Lab Groups
and Roles
 Makes sure everyone keeps goggles on at all times and are not engaging in
off-task or unsafe behavior
 Makes sure gas/Bunsen burner is turned off at the end of the lab
3. Materials Manager
 Responsible for getting the goggles for each person in your group
 Makes sure goggles and lab aprons are put away at the end of lab
 Cleans lab bench at the end of lab – wipe any excess water off lab bench.
4. Spokesperson/Assistant Group Facilitator
 Relays group answers to pre or post-lab questions during class discussions
 Ensures that each student gets the opportunity to participate in the
laboratory (everyone gets a chance to use the loop and the flame)
 Aids group facilitator in keeping group focused and on-task
 You will take turns reading the introduction to the lab in your
 Once you have finished reading the introduction, you will begin
your lab write-up on page 24 and 25 of your notebook. (*Note you
can write the title and begin the lab report below your daily warmup)
Flame Test Lab
Notebook Set
 You must include:
Names of all group members, Date, and Period (3 pts.)
Title (3 pts.)
Purpose (3 pts.)
Pre-Lab Answers (18 pts)/ Answer in complete sentences
Table (20 pts.) – you must write this in your notebook
Post Lab Answers (50 pts)/ Answer in complete sentences
 Once you have properly set up your notebook you can begin
answering the pre-lab questions
 Wear goggles at all times.
 You must tie long hair back (see me for hair tie if needed)
Flame Test Lab
 No Horseplay – anything I see that I feel is unsafe and/or places
you or your classmates in danger will result in your removal from
the lab. If you are removed from lab you will be required to work
on bookwork for the rest of the class period.
 When collecting the metal solution with your loop, gently dip the
loop in the beaker. Do not place the entire metal wire in the
beaker or bend the wire.
 Place only the wire loop in the flame
 ALWAYS be aware of the flame – do not reach over it, or clutter
your lab area with paper