• Students will be able to explain how the body acts like a system.
• Students will calculate the amount of sugar in their blood.
• Students will be able to describe how concentration of solutes affects viscosity.
• Students will use evidence to give a diagnosis to a patient.

The solution to pollution is dilution. The blood in the body does not exactly work this way. In fact, people can develop a complex disease called diabetes from long-term exposure to too much sugar. The Centers for Disease Control (CDC) estimates that about 10 percent of people have diabetes in the United States (CDC National Diabetes Statistics 2020 Report). This activity will have students learning about blood sugar concentration, the filtering system of the kidneys and the primary measurement that doctors use to monitor diabetes. The students will discover how much sugar they would expect to find in their blood.

Teacher Preparation

Print out the Investigating Blood Sugar Lab Notebook and the Mock Patient Chart for every student. Prepare materials for the comparing solutions portion of the lesson. The lesson is designed for 24 students with six groups of four students.

Use a part of the corn syrup to create 0.5 liter of each of 3 solutions:

• Solution A: 255 ml (17 tablespoon) of corn syrup in 245 ml of water
• Solution B: 375 ml (25 tablespoon) of corn syrup in 125 ml of water
• Solution C: 500 ml of corn syrup
• Solution D: 135 ml (9 tablespoon) of corn syrup in 365 ml of water

Create a display set of beakers or test tubes that have the following amounts of the above mixtures. Keep these hidden until the discussion of the solutions at the end of the lesson:

• 4 tablespoons of solution D
• 3 tablespoons of solution A
• 2 tablespoons of solution B
• 1 tablespoon of solution C

Label a set of paper cups A, B, C or D for each student group. Place 30 ml (2 tablespoons) of the corresponding solutions in each so they are ready for distribution to the student groups.

Note: Keep the below stats for when students calculate how much blood/blood sugar is in their bodies later in the lesson:

• Beaker C: 100% corn syrup is equivalent to 1.8 g/ml
• Beaker B: 75% corn syrup is equivalent to 1.35 g/ml
• Beaker A: 50% corn syrup is equivalent to 0.9 g/ml
• Beaker D: 25% corn syrup is equivalent to 0.45 g/ml

Reference:

• Can of Coca Cola: 0.1098 g/ml
• Blood sugar: 0.00095 g/ml

Lesson Plan

Using the Investigating Blood Sugar Slide Show, begin by having students review the medical case of Katie, their patient (slides 2 and 3). Give them time to discuss what they notice about her symptoms. Tell students that their goal for this lesson is to provide Katie with a diagnosis and a treatment option.

Part 1: Systems
Show students the images of the two systems (slide 4). Ask them to record what they know and what they are curious to learn about systems in their Investigating Blood Sugar Lab Notebook.

Point out that systems have boundaries that keep it contained. They have inputs and outputs to the system as well as components in the system that perform the function.

Ask students to think about how their school works as a system and to label the diagram in their lab notebook. Encourage students to think about how the school functions and supports the status quo. The inputs should balance the outputs to create a working system. For example, school lunches are brought in and garbage is put out.

Ask students to think about how their body works as a system. Prompt students to label the diagram in their Investigating Blood Sugar Lab Notebook, then have students write down what smaller systems make up the body system.

Using the systems organizer on page 2 of the lab notebook, have students fill out what they know about the circulatory system. They will fill in more information on this organizer later in the lesson.

Part 2: Solutions
Using the Investigating Blood Sugar Slide Show (slide 12), ask students to tell you what they know about solutions. As an example, discuss how they can dissolve drink mixes in water to create lemonade. Prompt them to write down their definition of solute, solvent and solution:

• Solute: Something that will dissolve in a solvent.
• Solvent: A liquid that can dissolve a solute into it.
• Solution: A mixture that contains a solute dissolved in a solvent.

Discuss concentrations within solutions. Students should identify which picture shows the most concentrated solution and be able to identify the picture with the most dots by the end of the discussion.

Ask students to think about which senses they can use to determine concentration. For example, students could taste lemonade to find out if it is highly concentrated, or students could use smell to determine if a perfume is highly concentrated in a room. In the following experiment, students will use touch to determine concentration.

Explain to students that viscosity is the term used to describe how concentrated a solution is. A highly concentrated solution will be more viscous than a less concentrated solution.

Refer students to their lab notebook for the comparing solutions experiment. Show students the objective and procedure for the experiment on the slideshow.

Comparing Solutions Experiment
Give each student group a set of 4 cups labeled A-D. Present the challenge with their objective: to rank the solutions from most concentrated to least concentrated. The only tools the students will have is what they brought with them to class and 4 straws.

Tip: Remind them that the solutions will cause a sticky mess. Recommend caution for spills, and request that students avoid putting anything in the solutions besides the straws.

Allow students 4 minutes to investigate the solutions. Students will use the straws as they see fit to decide the sugar concentration. Encourage students to be creative on how to use the straws.

When finished the students should describe the differences between each solution and be ready to share a description on how they decided the order. Have students record their findings and answer the questions in their lab notebook. The correct order from most concentrated to least concentrated is C, B, A, D.

Part 3: Blood Sugar 
Discuss the role of the kidney in filtering blood. The kidneys are important to consider for this patient because glucose was found in her urine. When the circulatory system reaches a threshold of sugar, it needs to get rid of the excess. The kidneys filter out the excess sugar. When sugar is removed from the blood stream, water follows because of osmosis. This is an important science concept that should be explored.

Show students the four test tubes of varying volumes. Ask students to discuss why the volume decreased.

Prompt student to guess how much sugar is in their blood. This will help us to understand Katie’s situation.

Discuss the composition of blood. About 55% of blood is plasma. Give students 2 minutes to discuss the discussion questions in the lab notebook.

Play the video: How Much Water Is in My Body?

Ask students to calculate the amount of sugar that is in the body using the table in their  Investigating Blood Sugar Lab Notebook. Students could either use their own weight or a fictional weight. The table is assuming a normal blood sugar value of 95 mg/dl.

Student values should be about 3 or 4 grams of sugar in their entire body. It may be helpful to measure out 3 grams of sugar for students to see.

Ask students to explain what the purpose of glucose is in the body. Glucose is an essential molecule that is used by cells, specifically the mitochondria, to produce ATP (energy).

Ask students to calculate the amount of glucose they need each day if they are on a 2,000-calorie diet. (1 gram of glucose is 4 calories.)

Discussion
Students should connect the idea that a lot of sugar dissolved in the blood would create a more viscous solution. This is bad for the heart and blood vessels. Also, when too much sugar is in the blood, it is released in the urine along with water. Therefore, we must eat throughout the day, and our circulatory system is constantly putting glucose into cells to be used as energy.

Show students the difference between normal blood sugar and Katie’s blood sugar. It equates to a difference of about 6 grams. Again, it may be helpful to measure out 6 grams so students can see the difference between normal and high blood sugar.

Discuss the role of insulin in regulating blood sugar. Insulin allows glucose to enter cells. Ask students to think about what would happen without insulin.

Show students the sugar range chart. Have them use the information to fill in the chart in their lab notebook and decide where Katie falls on the scale.

Explain the symptoms of hypoglycemia and hyperglycemia. Most students will have experience with hypoglycemia. Ask them to recall what it felt like when they skipped a meal. Hypoglycemia is easily cured by eating snacks. Hyperglycemia is not easily cured. People with hyperglycemia need to be seen by a doctor.

Ask students to get out the systems organizer and add any new information they have acquired. Specifically, the organs involved in regulating blood sugar. Students should share with a neighbor and then as a class.

Here are some of the elements that should be included in the organizer:

• Inputs: glucose (2,000 calories)
• Output: ATP (energy) and waste removed through urine 
• Components: Heart, insulin, blood, plasma, kidneys, urine and blood vessels
• Function: Blood has sugar dissolved in the plasma. Sugar is brought to all the cells. Insulin helps glucose get into the cells to produce ATP.

Ask students to think about what Katie's body is missing. Have them circle problems with the system in their organizer. Answer: She has a buildup of sugar in her blood. Sugar is being removed, along with water, through her urine. This is causing high blood pressure and thirst. The glucose is not getting to her cells. She is missing a component of her circulatory system.

Next, students can create a diagnosis for Katie and record it on their systems organizer. Encourage students to provide rationale and evidence for their diagnosis. Ask students to give a suggestion for a treatment (input).

Discuss Katie’s actual diagnosis of diabetes. Her high glucose level created the symptoms of high blood pressure, thirst, frequent urination, dizziness and weight loss.

Sanford Connection
Katie’s symptoms are typical for what an unknowing diabetic patient might visit a hospital feeling like. Sanford Health cares for patients with diabetes using many approaches, such as diet and exercise regiments, internal medicine specialists and pharmaceuticals. In addition to medical doctors and staff, researchers at Sanford Research are investigating the basic mechanisms of type 1 and type 2 diabetes in both clinical trials and basic science to help optimize treatments.

Learn about the newest clinical trials here.

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