STEM Face Off: Which Lesson Makes the Grade?

A MiddleWeb Blog

Just a few years ago I can actually remember typing STEM education into a search engine and having almost nothing come up. Try that now and you’ll discover a mind-boggling number of hits. Type in STEM lessons and the same thing happens.

The problem I face when searching for online STEM lessons, or when looking at books purporting to offer STEM lessons, is that quite a few of them don’t seem to be STEM lessons – at least not according to the way the National Academies of Science and of Engineering view K-12 STEM. (See my recent post STEM 2015: Are We Losing Our Focus? for more about these definitions.)

To explain what I mean, I’ve put together brief synopses of two lessons. Both are billed as STEM instruction. Based on your current thinking about STEM, what do you think? Are they both STEM lessons?

Sample Lesson 1: Growing Crops for a Lunar Biosphere

NASA engineers announce that in the future they will establish a lunar biosphere to support teams of scientists and engineers as they study the moon. Student teams decide to determine what crops might grow fastest and provide the largest mass yield for a lunar biosphere. Student teams set up and monitor classroom biospheres over a four week period. Crops tested include sweet potatoes, lima beans, collards, squash, radishes, and oats. 

Each student team selects a different crop. All teams then follow the same set of procedures and start their crops from seeds, planting them in plastic containers that will be tightly closed. The amount of light is held constant for all containers so that the only variable is the plant size and mass. As team members monitor the growth of their crops, they track crop height and growth rates. Teams take photos of the crops at different stages in the growth cycle.

At the end of four weeks students harvest the crops, measure the mass of the crops (after drying them), and determine which crops produced the highest mass yields. They compare and analyze data across teams, and select crops they believe to be good candidates for producing food and biomass in a lunar biosphere.

Each team writes a technical report to an imaginary NASA Lunar Engineering Team, recommending the specific crops they selected.

Sample Lesson 2: Designing an Air Cushion to protect fallers from injury

Prompted by an incident in which a worker fell from a construction site, student teams decide to design a cost-effective air cushion that will protect someone who falls from a high structure from injury.

The teams begin by studying acid-base reactions. Each team has access to a variety of materials and figures out a way to produce a predictable, controlled acid-base reaction inside a plastic bag. Team members then investigate the amounts of sodium bicarbonate and acetic acid that they think will produce enough gas (carbon dioxide) to inflate a gallon-size plastic bag to a size that would protect a person falling – not allow that person to touch the ground or bounce off the cushion.

Each team constructs its air cushion. Teams evaluate the success of their air cushions based on the condition of a model faller (a portion cup with 10 pennies) dropped onto the cushion from a height of 1½ meters.

Teams compare their air cushion designs with those of other teams, collect data on the results of all drops, and construct scatterplots. They then use the information to redesign their airbags to increase their effectiveness.

Each team videos a successful test and includes the video with a technical report to a company that will market this product.

So what do you think? STEM or not STEM?

For what it’s worth, here’s my take, based on the original vision of STEM:

> Both lessons involve science AND mathematics – a must for K-12 STEM, which is viewed as an integrated curriculum involving science, technology, engineering, and mathematics.
> Both involve teamwork – another “must have” for STEM curriculum.
> Both involve a student-centered, hands-on approach.
> Both focus on a real-world problem.
> Both involve collecting and analyzing data, although with different degrees of depth.

Although both lessons share these five characteristics, at this point the similarity to an actual STEM lesson begins to dwindle for Lesson #1.

Where the lessons diverge

Consider the design aspect. Lesson #1 offers students no choice (except for the plant type) in designing the solution. All teams are given the same approach to follow to set up their biospheres. Lesson #2, on the other hand, allows team members to work together to design the mix of chemicals, a way to combine the chemicals within a plastic bag, and the degree to which the bag is inflated to be successful. Each team may come up with a different mix of chemicals and amount of inflation. Lesson #2 permits multiple possible solutions for the problem.

Consider the process of designing and creating prototypes. This was absent in Lesson #1, but was front and center in Lesson #2. In Lesson #2 teams experimented with the chemicals and used this research to choose a design they believed would solve the problem. Each team then created an air cushion prototype from their design.

Consider the testing process. Lesson #1 offered no reason to do anything beyond gathering data about the mass of the plants. Lesson #2 involved teams in conducting actual tests of their air cushions and comparing the data graphically. That gave them information to help in redesigning their air cushions as needed.

The all-important engineering component

In my view, Lesson #1 did not fully match the criteria for a STEM lesson. Actually, Lesson #1 is a great science experiment and could qualify as research for designing a lunar biosphere. It followed the scientific method quite nicely, but it lacked an actual engineering application.

Lesson #2 contained that all-important engineering component – the component that drives real STEM lessons and projects. It followed the engineering design process and called on students to create their own research-based solutions for the problem (within constraints). This reinforced an engineering mindset of continual improvement and redesign.

Good lessons aren’t always STEM lessons

Many worthwhile lessons and projects focus on student-centered learning, innovation, creativity, teamwork, design approaches, and some of the same skills that STEM projects focus on. For that reason, many people think of these as STEM.

However, recall that STEM was introduced into the K-12 curriculum to meet specific (engineering-related) needs in our national workforce, as well as to create STEM-literate citizens. For that reason, I’d suggest sticking with the original purpose of STEM in our K-12 program designs. Let’s keep that all-important engineering component front and center.

Image credit: Lunar farm, Space Science Institute