Classroom Activities
As students will be tasting things to make observations during each of the following activities, it is highly important that I know about any allergies or other reasons why a student may not be able to fully participate in the activity. In some cases, a substitution may be made that would allow the students to join in on the eating. I will be asking both the parents, and the building nurse if there are any students that need to refrain from tasting any of our substances.
Physical Change – Crumbling Graham Crackers
To introduce the unit, I will challenge the students to turn and talk with a partner about the various things that scientists do. In my district, the students will have learned about this topic in kindergarten, but even for students not specifically taught the content prior to arriving at my class I would expect that they will be able to identify some skills related to scientists. After the turn and talk is complete, I will ask students to share out the answers that either they or their partner identified. I will write these responses on chart paper to later be transferred to an anchor chart labeled ‘Things that Scientists Do’. Specific answers I will be looking for are: making observations, predicting or hypothesizing, measuring, and communicating. There are many other skills that scientists develop and use but these will be focal points in the unit activities. Should the students miss one of these focal skills of scientists, I will guide the students to those answers and include them on our chart. I will then provide each student with a ‘Science Journal’. My class will be using primary notebooks though stapling lined paper would also serve the purpose. I will explain to the students that our journal will be where we record our learning or understandings from an activity. I will invite them to use a combination of pictures, labels, or age-appropriate sentences to share their thoughts on the activity. I will explain to the students that we will ‘do what scientists do’ as it relates to a special object: a graham cracker. I will invite students to share what they know about graham crackers. Following their shares, I will hold up a graham cracker and review the history of the snack using the information found in the ‘content objectives’ portion of this unit under the subtitle ‘graham crackers’. Following the review of the history of the graham cracker, I ask the students to not eat the cracker yet. I will challenge them to draw the graham cracker in their journal and to label it with its name. Upon the completion of the journal entry, I will ask the students in what skill of a scientist they had they just engaged. They had just made an observation and recorded their findings. I will ask them which sense they used to make the observation (sight). I will then ask the students what other senses we could use to make observations. I would anticipate them jumping straight to taste, but they could also use smell or the sense of touch. The students will then engage their sense of smell to make an observation. They will also record their findings in their journal. I will assist the students with spelling by having them provide some words that relate to the smell of the graham cracker. I will correctly spell these words on chart paper or the blackboard so that the students may properly transcribe them into their journal. I will use this method of providing correct spelling throughout the activities in the unit. The students will then repeat the process for the sense of touch and lastly, taste, recording their findings in their journal. Following that, I will provide another graham cracker to the students, with the directions to not eat it included again. I will tell the students that we will now change the graham cracker. I will ask students to volunteer ideas on how they could change the cracker. I would anticipate them suggesting that we could break them or crush them. I will provide each student with a plastic baggie and ask them to put the graham cracker inside the bag but to not seal it (I don’t want them popping their bag and getting crumbs all over their workspace.) I will demonstrate how I would pulverize the cracker and then invite them to crush theirs’ as well. Once crushed, I will ask the students to turn and talk to predict an answer to the following questions: has the graham cracker been changed? And is the new form still basically graham cracker? I will then instruct the students to make and record observations of the cracker crumbs using their senses of sight, touch, smell, and taste. I will ask the students if crumbs look different than a graham cracker. I would expect them to discuss the change in size from a rectangular cracker to a pile of crumbs. We can also compare the color of the crumbs to the color of the unbroken cracker. We will also compare the before and after crushing, texture, smell, and taste. I would expect them to agree that neither smell nor taste has changed. I will end the activity by informing them that the change we made to the cracker was a physical change. I will then define this term as ‘a change to a substance’s form’.
Chemical Change – Roasting Marshmallows
This activity is very similar to the previous one. The introduction to the activity is mildly different; instead of focusing on learning from kindergarten, I will guide student attention to the anchor chart labeled ‘Things that Scientists Do’ and instruct them to turn and talk with a peer about the following prompt, ‘what skills did we use yesterday that are skills that scientists use also’. As the students discuss, I will circulate throughout the room asking guiding questions about which skills were used during different portions of the past activity. Following the discussions, I will call on students to share their thoughts on the prompt. We will again focus on the skills of making observations, developing a prediction or hypothesis, and communicating ideas. I will then display to the students a marshmallow. I will invite the students to share what they know about marshmallows. As students share their thoughts I will record them on a chart paper. I am positive that at some point a student will mention that they roast marshmallows over a fire. I will then present each student with a marshmallow and ask them to observe the item using multiple senses, with the last sense being that of taste. The students will record their observations in their science journal using pictures, labels, and age-appropriate sentences. I will assist with spelling. After the journaling, I will have the students turn and talk and discuss ways that they could change the marshmallow. I anticipate that the students may offer the idea of tearing the marshmallow apart. If they don’t, I will suggest the strategy. I will then pull a marshmallow into pieces and ask the students if the marshmallow has been changed. I expect that they will agree that the marshmallow has undergone a change. I will ask them if they remember what words we use to describe when ‘a change to a substance’s form’ has occurred. They should respond with the term ‘physical change’. I will then ask them to draw the torn marshmallow in their journal and to label the picture a ‘physical change’. I will then let the students know that there is another kind of change that scientists, or even a kid camping can bring about to a marshmallow. I will explain that this new change is known as a chemical change and that it happens when ‘a substance is changed into a brand new substance, and it cannot be easily turned back into what it was before’. I will ask them if smashing a graham cracker is a chemical change. They should respond in the negative because even though the cracker pieces are very tiny after being crushed, they are still pieces of graham cracker., it is not a new substance. I will ask them about a kid camping and how that kid can cause a chemical change to the marshmallow. I will take ideas from the students. I am certain using the embedded clue in the question, that students will identify roasting a marshmallow over a fire would cause a chemical change. I will challenge the students to predict whether the marshmallow will look, smell, taste, or feel the same after cooking. We will then roast a marshmallow. My preferred way of doing this would be to use the bus court (or another outdoor space) to set up a small grill/firepit. Given approval from the office to engage my young students near open flame, I envision drawing a circle around the source of fire. I would need to provide the students with sticks or long marshmallow skewers for the roasting. While I would position myself close to the flames, the students would remain outside of the circle roasting from a couple feet away. While I would prefer to allow the students an opportunity to roast a marshmallow, I am prepared to demonstrate roasting marshmallows should administration be more comfortable with that choice. Either way, the students should see a beautifully tanned marshmallow as well as a blackened burned marshmallow. Following the roast, I will ask the students to make observations regarding the cooked treat. I anticipate that students will identify changes to the look, smell, taste, and even feel of the marshmallow post roasting. Those observations will be added to their journal. The students will draw pictures of the roasted marshmallow and underneath said pictures, label it a chemical change.
Mixture: Physical Change – Churning Ice Cream
I expect this activity to take two class periods. To begin the final activity of the unit I will introduce and read the book Ice Cream by Elisha Cooper. I will challenge the students to remember different stages that the milk or cream go through to become ice cream. I will also ask them to recall some of the many ingredients the book mentions as going into the ice cream. Following the read-aloud, I will specifically go through the steps taken at the ice cream factory to transform the milk to the final product. If time allows, I may have the students draw in their journal something that stood out to them in the book and to then write a sentence that explains what is occurring in the picture that they had drawn. As the period closes, I will tell the students that during the next class they will be like the scientists in the ice cream factory, and that they will make ice cream in class.
To start the second day of the activity I will again invite the students to share some of the ‘Things that Scientists Do’. I expect the students to supply the answers, make observations, make predictions or hypothesizes, and to communicate their ideas. I will then add a skill that we may not have mentioned before; scientists often read to learn about the focus of their studies, much like we read a book about making ice cream last class. I will then record “read to learn’ on the ‘Things that Scientists Do’ anchor chart. I will then share a bit of the history of ice cream from the information located in the ‘Content Objectives’ section and the subsection ‘Ice Cream’. I will then remind the students that in the book, Ice Cream, we learned that the factory uses big machines to churn the milk into ice cream. I will let the students know that we do not have a big churning machine in the classroom, but that I know another person that also does not have a giant churning machine but can make ice cream. I will show them a video of a person churning ice cream. I found many videos that featured people churning ice cream online. A simple search on YouTube should provide you plenty to choose from. Though I caution that I would not recommend showing any video to students that has not been previously viewed all the way through. I will challenge the students to recall what ingredients are churned together to create ice cream. I will then tell the students that we will use very common items to make our ice cream. I will show them quart and gallon sized Ziploc bags. I will provide each group of students 2 one-gallon bags and 2 one-quart bags. I will then direct the students to watch as I model each step in the process and then give them the opportunity to do the steps themselves as a team. I will ask the students what ingredients did the book and the video indicate are in the recipe for ice cream. I will be looking for the following ingredients: heavy whipping cream or milk, vanilla extract, and granulated sugar. I will demonstrate how to add the ingredients to one of the quart bags. I will begin by modeling how to use a measuring cup to add one cup of heavy whipping cream to the quart bag. The student teams will the use measuring cups to add the cream to the quart plastic bag. Following that I will model using a measuring spoon to add ½ teaspoon of vanilla extract to the quart bag already containing the heavy whipping cream. The students will be provided with a ½ teaspoon and the extract. They will add the new ingredient to their quart bag of cream. Finally, I will add 2 tablespoons of granulated sugar to the ingredient bag. I will show the students how to level the sugar in the tablespoon and I will add the sweetener to the other ingredients. The students will do the same paying special attention to measuring out the sugar called for by the recipe. I will then seal the Ziploc bag of ingredients and insert the sealed bag into the empty quart bag and seal that one as well. The students will repeat the process with their doubled quart bags full of ingredients. I will then ask the students if the person churning ice cream in the video used any additional substances to make the ice cream. The answer should be yes, if your video does not show ice and salt being used in the process, I suggest you find a video that does. I will explain that we need to use ice cubes and salt make the cream mixture change to ice cream. I will model filling one of the gallon bags half full of ice cubes. Student teams will then copy the process with one of their gallon bags. When all student groups are done adding the ice cubes, I will model measuring and adding 1 cup of rock or coarse salt to the ice cubes in the gallon bag. Student groups will complete that step also measuring the amount carefully. I will model placing the double-quart-bagged ingredients into the larger gallon bag half filled with ice and salt and then sealing the larger bag closed. The students will follow suit. Lastly, I will model placing the full gallon bag inside of the empty gallon bag and sealing it closed as well. The students will do the same. I will then distribute a dish towel to each team. I will model wrapping the towel around the sealed bags and explain that the bag of ice can get very cold as we transform the ingredients into ice cream. I will then explain that our ‘churning’ will actually be us shaking the bag vigorously for 5 or so minutes. I’ll tell the students that when their arms become tired or their hands cold, they should pass the bag to a partner and continue. I will put some music on the Smartboard that will be good to inspire shaking the bag. While the groups shake the ingredients, I will circulate observing the cream as it thickens. When it seems that all groups have successfully ‘churned’ ice cream, we will remove the gallon bags over the classroom sink. We will then open the quart bags of ice cream. We will use spoons to scoop some ice cream into small bowls, which I will provide, and the students will make observations about the ice cream including, how it looks, smells, feels, and tastes. These observations can be added to our journal. I will then ask the students if the milk, vanilla extract, and sugar have undergone a physical or chemical change. I fully expect the students to suggest that a chemical reaction has taken place since the ice cream will seem like a new substance after the churning. I will explain that making ice cream is actually a physical change because we have created a mixture which is defined as ‘putting two or more substances together, but they do not make up a brand-new chemical’. I will ask them to draw and label the ingredients (but not the ice and salt) in their journal and to then draw and label ice cream as well.
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