I start the lesson by activating background knowledge from prior lessons. I do this by setting a two-minute timer, asking students to write down as many examples of physical changes as they can think of. After two minutes are up, I perform a quick Whip Around and have students each name one example, continuing the Whip Around until nobody can name any more accurate examples that haven't already been said.
I explain to the students that while we have had a lot of discussion about physical changes, we haven't really talked about chemical changes. I tell then that chemical changes are different from what we have recently studied, and offer the opportunity for volunteers to share what they already know about this topic.
Next, I show the Chemical and Physical Changes video:
After the video, I perform a Whip Around similar to before, but this time we list chemical changes. The students will not be able to name as many as they did in the first round, but it will start to help them understand the difference between the two.
I explain to the students that we will focus on one specific chemical change today known as the Maillard Reaction. I tell that that the Maillard Reaction takes place when cooking several foods, including (but not limited to) coffee beans, bread, cheese, meats, and even popcorn! In order to gain an understanding of the Maillard reaction, I have the students watch The Maillard Reaction video, taking notes as they watch:
After watching the video, I pass out one pink or blue index card to each student. (I use pink for higher level readers and blue for lower level or reluctant readers.) I have students get into groups of 2-3, selecting partners from those who have the same colored card. Once the students have formed their groups, I pass out articles on the Maillard Reaction. (I have included two different articles based on reading level.) The students read their articles and summarize them within their group.
They will then pair up with someone who has a different colored card to explain their reading. Because each article is quite similar, they will need to revisit the reading at least once and provide details in order to share information that their partner did not learn from their own article.
For more information on leveled reading in science, please watch the video below and read my reflection!
Now that the students are familiar with chemical changes, and more specifically, the Maillard Reaction, they have the opportunity to see it first-hand!
*For this activity, I usually elicit the help of parent volunteers to make sure students are working safely and using proper hygiene practices.
I start by having each student wash, dry, and sanitize their hands. Then I send them to 4-5 stations around the room, each of which is equipped with:
Each students gets the opportunity to toast one bread product. Once they have made their treat, they also get the pleasure of eating it!
In order to determine the students' ability to discern between chemical and physical changes, I have them complete the Physical/Chemical Change Assessment. In this activity, students watch several short video segments and determine if a chemical or physical change has occurred, explaining why they think so. I also have them respond to the following prompt at the bottom of their paper:
Provide evidence that the Maillard Reaction is an example of a chemical change.