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Dr. Drew, Density, & Diffusion: Dr. Charles Richard Drew Giving Life Through Blood Research

Dr. Drew, Density, & Diffusion: Dr. Charles Richard Drew Giving Life Through Blood Research

Download the accompanying PowerPoint about Dr. Charles Drew

Dr. Charles Drew was an African American physician and blood transfusion researcher in the early 20th century. His research laid the foundation for modern blood banking through the creation of blood collection and storage techniques, many of which are still used today. Through a series of lessons, participants will revisit Dr. Drew’s story as an African American physician and researcher in the early 1900s by engaging in activities on density, diffusion, and the circulatory and respiratory systems. We want students to develop an appreciation for Dr. Drew’s contributions and to understand the STEM principles behind his work.

Dr. Drew, Density, & Diffusion: Dr. Charles Richard Drew Giving Life Through Blood Research is part of the STEM2D Student Activity Series. The content was developed by the National Museum of African American History and Culture, Education Department, the Teaching and Learning Unit and generously supported by The Dow Chemical Company.

The layout was designed by the Smithsonian Science Education Center as part of Johnson & Johnson's WiSTEM²D initiative (Women in Science, Technology, Engineering, Mathematics, Manufacturing, and Design), using a template provided by FHI 360 and JA Worldwide. This series includes a suite of interactive and fun, hands-on activities for girls (and boys), ages 5-18, globally.

Introductory Activity: Connecting the Circulatory and Respiratory Systems

This activity will introduce your students to the circulatory and respiratory systems and the connections between them. Before beginning this activity with your students, find out what they already know about the circulatory and respiratory systems by introducing questions such as, “why do we breathe,” and “why do our hearts beat?” Throughout the activity, there are opportunities for the students to share their predictions and the reasoning behind them on what they think will happen after doing different activities.

This session typically takes 20 minutes​ to complete. This activity is optional.

Activity 1: Density Tower

The density tower activity introduces students to the concept of density and is easily connected to STEM concepts of weight and volume. Present this activity as a scenario.

Example: The students are working for a drilling company interested in collecting all of a particular liquid from the column. They will be responsible for predicting where the liquid will be in the column by using the density values and by measuring distance from the top of the graduated cylinder. To correctly complete their task, they must predict where each liquid will rest compared to the others. This activity will engage them in working with <, >, and = and will also encourage their use of a ruler either using metric or imperial units. Until you are confident in your students’ abilities to pour and layer liquids gently, it is important that they follow the instructions below.

This session typically takes 20 minutes​ to complete.

Activity 2: Diffusion in Liquids

The diffusion activity allows students to engage with the concept of diffusion in liquids by manipulating multiple variables impacting its speed including energy, temperature, and container shape (surface area). Diffusion is the random movement of molecules from an area of a high concentration to an area of low concentration. For these diffusion experiments, it is important that groups use the same color for all their experiments because dye molecules can be different molecular weights, which will lead to different results. This is also an interesting test to perform. Present this activity as a scenario.

Example: When presenting the diffusion and container shape activity to your students, turn it into a challenge to be addressed. You can use the real-life scenario that Dr. Drew and other blood researchers were faced with. Tell the students that we need to select the container that keeps the water from reaching equilibrium as long as possible. Like the experience of Dr. Drew, we want to use a container that slows the diffusion process. Dr. Drew was trying to slow the spread of potassium from the red blood cells into the plasma. You are trying to slow the movement of food coloring into the water.

There are two container options. Once the students identify the best container to use, they will then need to discover if the diffusion process can be slowed using different temperatures of water.

This session typically takes 30 minutes​ to complete.

Activity 3: Diffusion in Red Blood Cells

This activity will introduce the students to how diffusion can occur across a membrane, like it does in our bodies. The students will build on their earlier concepts of diffusion to construct a physical model of the red blood cells in our bodies and how diffusion of gases occurs in our bodies. When presenting the red blood cell model to your students, this is an opportunity to engage students in the concepts of surface area, volume, size, and scale.

This session typically takes 30 minutes to complete.

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