The Arizona STEM Acceleration Project
Mystery Powders
Crime Busters: Mystery Powders
A 5th Grade STEM Lesson
Author: Tonya Page
Date: Jan 3, 2023
Notes for Teachers
Prior to the lesson: (30 min)
During the lesson:
List of Materials
Science & Math Standards
Arizona Science Standards
5.P1U1.2 Plan and carry out investigations to demonstrate that
some substances combine to form new substances with
different properties and others can be mixed without
taking on new properties.
Next Generation Science Standards
5-PS1-2. Measure and graph quantities to provide evidence that regardless of the type of change that occurs when heating, cooling, or mixing substances, the total weight of matter is conserved.
5-PS1-3. Make observations and measurements to identify materials based on their properties.
5-PS1-4.Conduct an investigation to determine whether the mixing of two or more substances results in new substances.
Math Standards:
5.MD.A.1 Convert among different-sized standard measurement units within a given measurement system, and use these conversions in solving multi-step, real-world problems.
5.G.A.2 Represent real-world and mathematical problems by graphing points in the first quadrant of the coordinate plane, and interpret coordinate values of points in the context of the situation.
ELA Standards
5.RI.1 Quote accurately from a text when explaining what the text says explicitly and when drawing inferences from the text.
5.RF.4 Read with sufficient accuracy and fluency to support comprehension.
5.W.2 Write informative/explanatory texts to examine a topic and convey ideas and information clearly.
5.W.1 Write opinion pieces on topics or texts, supporting a point of view with reasons and information.
5.W.4 Produce clear and coherent writing in which the development and organization are appropriate to task, purpose, and audience.
5.W.6 With some guidance and support from adults, use technology, including the internet, to produce and publish writing as well as to interact and collaborate with others; demonstrate sufficient command of keyboarding skills in order to complete a writing task.
5.W.7 5.W.8 Conduct short research projects that use several sources to build knowledge through investigation of different aspects of a specific question or topic.
Objective(s):
Today students will collaborate and communicate together to solve a problem through inquiry and investigation while using qualitative and quantitative observations to identify multiple mystery powders and their characteristics of physical and chemical reactions when mixed with known substances.
Today students will compare and contrast observations of pertinent details taken while investigating.
Today students collaborate to collect qualitative and quantitative measurements to identify unknown cupboard ingredients.
Today students will use science and engineering practices to effectively problem solve.
Today students will effectively communicate their data and inquiry results.
Agenda (90 minutes)
Pre Teach (30 min)
What are qualitative and quantitative observations?
What are physical and chemical changes?
How can I practice safety throughout lab experiments?
Lesson (60 min)
Introduction to Forensics careers
A day in the life of a forensics technician
A day in the forensics lab
CSI: Introduction to the crime- Who stole it?
Forensics video-how to test unknown powders
Distribute materials and guidelines
Experimentation time/Hands-on Activity
Share or Present findings
Pre-teach
Video: What are qualitative and quantitative observations?
Student reading: Changes in Matter: Physical vs Chemical Changes
Video: Crash Course on Chemical and Physical Changes
Assessment: Chemical and Physical Changes
Practice safety in the classroom assessment.
Video: Qualitative vs Quantitative Data
Qualitative observations are those that describe the situation using anything that does not use a number or measure. For example, the sun is bright today.
Qualitative Examples:
gender
religion or marital status
color
native language
social class
bubbles
heat
sizzling
steam
method of treatment
Quantitative observations are those that use a number in the description (weight, time, number of items, height, volume, and so on). For example, the temperature is 78 degrees Fahrenheit right now.
Quantitative Examples
age
height
weight
income
group size
test scores
shoe size
percentages
ratings
Video: Crash course on physical and chemical changes
What is a Physical Change?
In a physical change, the material involved in the change is structurally the same before and after the change. Types of some physical changes are texture, shape, temperature, and a change in the state of matter. A change in the texture of a substance is a change in the way it feels. For instance, a block of wood may feel rough when you run your finger across it but rubbing the wood with sandpaper smooths the surface so it no longer feels rough. The wood itself has not changed during sanding to become a new material, only the texture of the surface changed. A piece of metal may be heated in a fire until it glows, but the metal is the same material before heating and after cooling. Similarly, when a material changes phase, it only changes physically; the substance is still the same. Think about ice melting into water, and then water being heated up and turning into steam. The chemical structure of water is the same whether it is a solid (ice), liquid, or gas (steam).
What is a Chemical Change?
A chemical change occurs when the composition of a substance is changed, which requires the breaking and forming of chemical bonds during a chemical reaction. This results in the rearranging of atoms in substances to form the products of a chemical reaction, which are brand new molecules that cannot be easily reverted back to their original state.
Sometimes it is difficult to tell if a chemical reaction has taken place. To help determine whether there has been a reaction, chemists consider the basic indicators that a reaction has occurred, such as a change in temperature, a change in color, the development of an odor, the formation of a precipitate, or the formation of a gas.
In a chemical alteration, the temperature change occurs as a result of the breaking or formation of chemical bonds. When the chemical bonds of the reactants are broken, sometimes excess energy is released, causing heat to be discharged, and leading to an increase in temperature. Alternatively, a reaction may require energy from the environment in order to take place, causing heat to be absorbed, and leading to a decrease in temperature. Burning wood is an example of a reaction that releases excess energy as heat. A chemical cold pack in a first aid kit is an example of a chemical reaction that absorbs heat energy resulting in cooling.
An example of a color change signaling a chemical reaction can be observed when iron reacts with oxygen to produce iron oxide, such as when an iron nail is left outside, and it develops a reddish-brown rust.
Rotting food is an example of odor development as a result of a chemical change. When food is left out for too long, or it reaches its expiration date, it eventually spoils, often producing a foul odor in its rotten state. This is because of chemical reactions that take place as the food begins to break down and go bad, which leads to the formation of new substances that have unique smells associated with them.
Another common sign of a chemical reaction is the formation of a precipitate. This happens when chemicals dissolved in a solution are mixed together and an insoluble solid, known as a precipitate, forms in the liquid mixture. The creation of a new, solid substance from two liquid substances indicates that a reaction has taken place and altered the original substances.
A common chemical reaction is the mixing of vinegar and baking soda. When these two household chemicals are mixed together, it immediately starts bubbling and foaming. The bubbles are a release of carbon dioxide gas, a product of the chemical reaction between the baking soda and vinegar.
Remember that the difference between a physical reaction and chemical reaction is that a chemical reaction cannot be easily reversed, if at all.
Mystery Powders Lesson
How can you use forensics science techniques with qualitative and quantitative data observations to help solve crimes in the real world?
Instructions
In groups of 2-4 use forensics science experiment techniques to match known chemical reactions of unknown powders to find a match to the crime scene.
Constraints:
Notes for Teacher
Hands-on Activity
Lab 1: Distribute the 5 powders for each group. A small sample (1 tsp) should be placed in each circle using a spoon. Students should make and record observations through sight, smell and touch. DO NOT TASTE! The first circle on each row is a control group. No liquid should be dropped on the control group.
Record observations on worksheet: Lab 1.
What does it look like?
What does it smell like?
What does it feel like?
Lab 2: Distribute liquids to test (water, vinegar, iodine) along with mL dropper for each liquid. Use a mL dropper to add 3-5 drops of liquid on each powder and observe changes and reactions. Take notes on chemical and physical properties happening. Students should look for color change, sounds, bubbles, texture differences, etc. See: Chemical and Physical Changes slides.
Lab 3: This may be used as a cheat sheet that will give clues how some substances interact and what to look for. You may want to go over this first for learners who need extra assistance, or use to compare and discuss after.
Success Criteria
Differentiation
Remediation
Extension/Enrichment