In this lesson, students will look at the chemistry of the molecules of carbohydrates, fats, and lipids, and they will use this information to determine a diet for their mealworm and will collect information about the mealworm to test a hypothesis.
By the end of this lesson, students will be able to
- Compose a comparative question.
- Explain the molecular structures of biological macromolecules.
This lesson supports students’ understanding of the following topics in chemistry:
- Molecular structure
Teacher Preparation: 20 minutes
Lesson: 45 minutes plus follow up time to collect data
For each group:
- 2 containers (a deli container or a disposable plastic container works great with holes in the lid)
- A water source (a piece of bread dipped in water or a carrot)
- 2 mealworms (these can be ordered from a local pet store)
- A variety of food (chips, cookies, vegetables, oats, fruit, etc.)
- Two slices of potato
- Mealworms do not bite; however, students may want to wear gloves or wash hands directly after handling them.
- To pick mealworms up, it is easiest to use a spoon or a flashcard; however they should not remain out of their natural habitat for too long, as they will need food and water.
- Mealworms should not be kept within direct sunlight.
Mealworms, digestion, balanced diet, protein, lipids, carbohydrates
This sections includes any information the teacher might need, including
- More information and ideas on how to use food chemistry in the classroom.
- Mealworms can be ordered from any pet store online. They should be kept in a refrigerator until they are ready for use. Keep them out of direct sunlight.
- For students at a higher level, it is possible to create an exercise routine for their mealworm as well. By placing the mealworm on a piece of paper and measuring how long it takes for the mealworm to reach an apple that is 20 cm away, students can compare times as the mealworm gets bigger and then compare to see if certain foods slow them down.
For the Student
Ask students student to list what they ate that day. Ask students, “Which food was your favorite? Was it a carbohydrate, lipid, or protein?”
- As a class, break down the elements in student lunches into lipids, carbohydrates, and proteins. Review the chemical composition of each of these three molecules (basic structure) and how their structure contributes to their function.
- Have students create their own comparative questions for what they would feed a mealworm based on discussion, “Would the mealworm grow faster with a diet of ______ or _______?”
- Have students come up with their own hypothesis to their question and support it with their background knowledge.
- Have students label their mealworms containers with their name and the food that the mealworm should receive.
- Have students take their container and create bedding of whatever food they have chosen to feed their mealworm. (They can crunch up potato chips, use dry oatmeal, crunch up cookies, rip up fruits or vegetables, etc.) Include a small slice of a potato for the mealworm to stay hydrated. They should do the same for their second container with their second food choice.
- Have students create a chart or use the chart in the Student Activity Sheet to record the weight and length of their mealworms each class. The chart should also include an area to record the percent change in mass so they can compare the changes in the mealworms every other day.
Mealworm with a Diet of ______ Mealworm with a Diet of ______
|Date and Time of Observation||
|% change in length||Mass (g)||% change in mass||Length (cm)||% change in length||Mass (g)||% change in mass|
- Have students weigh out their mealworm and record the weight.
- Have students measure the length of their mealworm and record the length.
- Repeat students repeat steps 6-8 every other day for a month. Students should also create a graph for both length and weight.
- Have students form conclusions about what foods were best for their mealworms.
Students will create a line graph with the length of their mealworms to show a comparison. Students will create a second line graph to show the comparison of the weights of their mealworms over time.
Students can explain what they think would be a good diet for their mealworms, based on the data collected from the investigation. They should be able to tell how this information can be applied to their knowledge of their diet, but they also should explain how the mealworms diet has to be different from their diet. They should look at the main molecules that make up the food and come up with similarities and differences. This discussion can shift towards how the food mealworms get contains energy and how cellular respiration contributes to this.
Students can create charts with their data, analyze the charts, and form conclusions based on them. This conclusion can be used as a final evaluation. The Student Activity Sheet provides questions that satisfy an evaluation.
Next Generation Science Standards
This lesson supports the following:
- Practices of Science and Engineering
- Asking questions and defining problems
- Planning and carrying out investigations
- Analyzing and interpreting data
- Constructing explanations and designing solutions
- Engaging in argument from evidence
- Obtaining, evaluating, and communicating information
- Cause and Effect: Mechanism and Explanation
- Scale, Proportion, and Quantity
- Substances are made from different types of atoms, which combine with one another in various ways. Atoms form molecules that range in size from two to thousands of atoms. (MS-PS1-1)
- Each pure substance has characteristic physical and chemical properties (for any bulk quantity under given conditions) that can be used to identify it. (MS-PS1-2) (MS-PS1-3)
- Within individual organisms, food moves through a series of chemical reactions in which it is broken down and rearranged to form new molecules, to support growth, or to release energy. (MS-LS1-7)
- Cellular respiration in plants and animals involve chemical reactions with oxygen that release stored energy. In these processes, complex molecules containing carbon react with oxygen to produce carbon dioxide and other materials. (secondary to MS-LS1-7)
- The more precisely a design task’s criteria and constraints can be defined, the more likely it is that the designed solution will be successful. Specification of constraints includes consideration of scientific principles and other relevant knowledge that are likely to limit possible solutions. (MS-ETS1-1)
- A solution needs to be tested, and then modified on the basis of the test results, in order to improve it. (MS-ETS1-4)
- There are systematic processes for evaluating solutions with respect to how well they meet the criteria and constraints of a problem. (MS-ETS1-2), (MS-ETS1-3)
- Sometimes parts of different solutions can be combined to create a solution that is better than any of its predecessors. (MS-ETS1-3)
- The iterative process of testing the most promising solutions and modifying what is proposed on the basis of the test results leads to greater refinement and ultimately to an optimal solution. (MS-ETS1-4)