CONTEXT
Moving Water: Start with a Context
For any STEM unit focusing on engineering, context this is essential. What are the real world issues, stories, history, that circumscribe the science concepts and engineering challenges? The contexts we choose should be rich in relating science and engineering to real people in real situations. In this unit we start with video presentations, then read excerpts, and show multimedia presentations to provide students with a broad context to the learning.
Let's start with the phenomena of drought. Most of us have heard the word and are familiar with the concept. We might introduce this to our students in an indirect way:
Ask students, "What is the difference between the two cornfield pictures below?"
Their answer is "water, of course." You might encourage their input on any difficulty they might have had with drought or water problems in their lives. Often students bring a great deal of practical experience to these kinds of problems.
Review with students that water is an essential ingredient for plant growth. Plants take in water and carbon dioxide from the air using sunlight as a source of energy to create plant cells. Everything we eat comes ultimately from plants because the animals we may eat find their food source in plants. Sustained dry periods and no access to water is one definition of drought. You might challenge students with the question, "What effects are there if there is drought and there is no corn crop?"
To give students a broad understanding of the scope of the issue, it is important to expand the context by having them read, watch, and talk about the problem. In the next segment there are short reading, videos and discussion questions to get them going.
Consider some guiding questions to help students direct their attention:
• What did you find interesting about the reading, video, and multimedia?
• What were the most important things you found out?
• What would you like to know more about?
Read a selection from "A Long Walk to Water"
An excellent overview of irrigation, agriculture, and the impact of drought can be viewed below:
In many countries around the world, drought does not just mean higher food prices, it may mean malnutrition or even famine. To help students see the human face on the problem of water shortage, read this news story from the Independent in 2011:
Suddenly there is talk of famine in Africa again. Ten million people are at risk of starvation in the worst drought conditions in 60 years in Ethiopia, Somalia and northern Kenya. Tens of thousands of people have left their homes in search of water and food. Hundreds of thousands of farm animals have died.
Every day some 1,200 Somalis are crossing the border into Kenya where, near the town of Dadaab, the world's biggest refugee camp, 50km square, has developed. Many of the children arriving there, after month-long treks across the unyielding desert, are so weak that they are dying despite receiving emergency care. Millions more are hungry and have begun the slow journey to wasting from malnutrition. You can also show short news stories about the effects of drought:
BRINGING IT HOME
International problems aside, it is also important to bring the problem close to home. Have students consider how much water it takes to grow a vegetable in the garden:
Imagine how much weight in water it takes to irrigate a simple garden plot 20 feet by 20 feet. If you are planting vegetables you need about 1½ inches of water per week applied to the plants. That means a 20’ by 20’ garden would need 50 cubic feet of water every week, or over 374 gallons! Would you like to carry 150 pails of water weighing 20 pounds each a week to this garden?
Imagine a situation where the source of water is a half mile away or further. Have students think about how much time a week they would spend just carrying water so the family might have a few vegetables to eat.
What can engineers do to help farmers move water?
There are many kinds of people who are working to solve the problem of getting enough water to irrigate crops. Engineers from around the world have designed many kinds of solutions, including these novel applications:
After reading, watching and talking about moving water, ask students to wonder: "What could you do to make a difference?"