The Case of the Missing Cake: Using a CSI Lab to Teach Chemical and Physical Changes

Everyone loves to solve a mystery, so The Case of the Missing Cake CSI Lab gets students excited to observe and classify physical and chemical changes!

The CSI Lab Scenario will definitely engage the students and make learning about physical and chemical changes much more interesting.

But, if you want to amp up the engagement, then you may want to decorate your classroom as a crime scene.

Add the caution tape.  Have an empty cake plate with a trail of white powder on the counter.  Dress up as a detective or crime scene investigator.  The more you sell this activity, then the more excited your students will be about learning the basics of chemistry.

Small classroom transformation #CSI #scienceclass #chemistry #science #teacherlife #teach #engage #teachersofinstagram lesson credit on TPT: @angelawillyerd

A photo posted by Esther Alvarez (@alvrze) on Oct 6, 2015 at 4:17pm PDT

Imagine being a student in your classroom when the room is staged like in the photo above.  Exciting, right?  In an instant, you have already captured their attention.  Then, you can explain the case.  In this lab, a cake decorated by a famous baker has gone missing from his bakery overnight.

It is up to the students to solve the case!  

Three suspects were found with white powder residue on their clothing.  So, the students must test samples of known and unknown substances to determine which suspect was the culprit.

The students will then observe what occurs when testing the known white substances with water, vinegar, and iodine.

Did it dissolve?  Did it fizz?  Did it turn colors?

Once the lab group discusses what was observed, then they classify the observation as a physical or chemical change.

Students will then be presented with unknown samples collected from the crime scene and each of the suspects.  They will then need to test these unknown samples as they did the known samples.

Once the results have been collected, then the data analysis begins.  You may have to walk through the data analysis with your students.  Help them be able to compare the known substance results to the unknown substance observations.

Can they determine which substance is which based on the observations?  Which sample collected from the suspect matches the observations made with the crime scene sample?  Who was the cake thief?

Thank you @angelawillyerd for your#TPT #CSILab It was a hit this year too! #teachersofinstagram Blog post soon!

A photo posted by Esther Alvarez (@alvrze) on Oct 4, 2016 at 12:56pm PDT

The fun part, as a teacher, is that you can always have some tricks up your sleeve.  If you are conducting this lab with more than one class, then you may want to switch up the crime scene sample.

The different classes will yield different results as to which suspect is guilty of stealing the cake!  This will keep the students on their toes and avoid any spoiler situations that are lurking in the hallways or cafeterias.  There is always one student who can't wait to share the verdict with the others!

This lab helped students collaborate with others, classify the observations as either physical or chemical changes, and encouraged higher level thinking with the analysis of the collected data.  Plus, it got students excited about science!  Yes!!

Are you interested in conducting this lab in your class but don't have the time to create the lab handouts or corresponding presentation?  Check this resource out in my TeachersPayTeachers store - it is available in PowerPoint and Smart Notebook formats.

Special thanks to Esther Alvarez!  She is a rock-star teacher in Texas who has conducted this lab in her middle school science class for a few years, and is always so nice to share the photos with me!  You can follow her on Instagram and Twitter.

 

How to Teach Good Procedure Writing: PB and No J Scientific Method Demonstration

I love teaching the scientific process

to start off the beginning of the year. It's the foundation for all other good scientific work that we will do throughout the entire academic year. I introduce the importance of good procedure writing with a fun and memorable demonstration called PB & No J.

Students are asked to write some steps for how to make a peanut butter sandwich as a type of pre-assessment. I usually walk around the room to observe the different skill levels of the students, since many of my students come to me with various scientific inquiry experiences. Then, I have a few volunteers to participate in the first part of the demonstration. Students experience poorly written procedures when trying to make a peanut butter sandwich. The student trying to make the sandwich in this demonstration automatically adds the unwritten steps since they have probably made a peanut butter sandwich before. It's a lot of fun for the class when the teacher polices this demonstration and calls the student out. "Did the instructions say to do that?" The classmates usually start shouting out ideas for what should be done, but as the teacher and facilitator, you want to get the point across that there is a lot of wiggle room with these procedures. You just
never know what should actually be done and need to do some guessing. That does not make for a clear and consistent procedure. I do allow students to be creative in opening the peanut butter jar and eating the sandwich - as long as it isn't with their hands. Always pick a student for this part of the demonstration who is generally outgoing and boisterous. You will know the perfect kid for each class who will help make this activity memorable.

The second part of the demonstration shows the students an example of well-written procedures. I usually try to over-emphasize on the detail, and then try to tell the kids that their procedures need to be a happy medium between the poor procedures and the extremely detailed procedures. Once the students have experienced both demonstrations, then I have them review the procedures they had written at the beginning of the activity. I ask them to self-assess on a rubric, and then have any super confident junior scientists try their hand at reading their procedure for someone to follow in front of the class. This is a great opening for a few other lab experiences that will provide the opportunity for students to continue refining their procedure writing skills. I can tell a HUGE difference in the student writing when I explicitly teach procedure writing with this activity versus years when I only mentioned how it was important to include detailed steps. PB & No J definitely makes an impression!

Do you love this activity but don't have a ton of time to think about writing all those procedures? Download the handout with a self-assessment rubric and t-chart as well as a corresponding PowerPoint on my TpT store here!

Mysterious M&M Lab Skills

Students sketched what they observed
when one M&M was placed in a bowl of 25 mL of water.

Students worked on developing detailed
written descriptions of what they observed. 

My seventh graders worked hard this week developing scientific inquiry skills by observing M&Ms in water.  The students were asked to learn how to sketch what they observe as well as provide a detailed written description.  Students then started developing their own experiments using different variables, such as: different color M&Ms, type of liquid, the temperature of liquid, and the number of M&Ms.  Students will then conduct their experiment on Monday to measure the rate of dissolution with the M&Ms under the condition they selected.

Mysterious M&Ms

Students in Mrs. Willyerd's 4th Period Class read the graduated cylinder
at eye level during the Mysterious M&M Lab.

This week students worked on becoming better scientists.  We really focused on making good scientific observations, constructing a well-written hypothesis that is testable, and summarizing the results in a conclusion statement.  Students conducted two labs in order to practice these skills - a gummy bear lab and the Mysterious M&Ms lab. 

The M&M lab had students examine one M&M and observe the texture, color, weight, size, state of matter, and any other observations the student could make.  Students then had to break open their M&M and sketch a cross-section of the M&M labeling the outer shell, the inner shell, and the chocolate center.  The next part used another M&M that was placed in the bottom of a shallow bowl.  Water was added to the bowl and students had to observe the M&M for one minute.  After the minute passed, the students then sketched and described their observations.  Ask your student what happened to their M&M!

Students were able to share their sketches and descriptions using our document camera on the Smart Board.  Sharing on the document camera helped students improve their work by receiving peer and teacher feedback.  It also provided a great incentive for students to try their best because the best one in the class would always be shown along with some other examples that might need some "fixing up."

An excellent sketch of a cross-section of an M&M by a first period student.

Next week, students design their own M&M lab that should include detailed procedures.  Today we did a Peanut Butter and No Jelly demonstration on how it was easy to follow detailed procedures and how it might be tough to guess what they should do when given poorly written procedures.  Hopefully, we will see some well-written procedures on Monday's lab!

A student in 6th period had to eat the peanut butter sandwich with no hands
when demonstrating what happens using poorly written procedures!

Are You a Molecular Gastronomist?

Have you ever helped your family prepare a meal? Then you might be a molecular gastronomist! Didn't think you were certified to be one? Well, science occurs in our everyday lives. You just need to observe carefully to notice how science is related to what you might be doing each day.

Watch this CBS video clip on Chef Jose Andres, who studies molecular gastronomy. What is molecular gastronomy? It is the study of (the suffix -onomy means "study of") the physical and chemical processes that occur while cooking.