Arizona STEM
Acceleration Project
Solutions and Mixtures: Taking the Salt out of Water: Desalination
Desalination:
Solving Our Need for Freshwater.
A 5th grade STEM lesson
K Mohamedeen
05/16/2023
Notes for Teachers
List of Materials:
5.P1U1.2 Plan and carry out investigations to demonstrate that some substances combine to form new substances with different properties and others can be mixed without taking on new properties.
5.P1U1.1: Analyze and interpret data to explain that matter of any type can be subdivided into particles too small to see and, in a closed system, if properties change or chemical reactions occur, the amount of matter stays the same
5.P2U1.3 Construct an explanation using evidence to demonstrate that objects can affect other objects even when they are not touching. ● All objects have an effect on other objects without being in contact with them. In some cases the effect travels out from the source to the receiver in the form of radiation (e.g. visible light)
Science and Engineering Practices
5.RI.3:
Explain the relationships or interactions between two or more individuals, events, ideas, or concepts in a historical, scientific, or technical text, based on specific information in the text.
5.W.8:
Recall relevant information from experiences or gather relevant information from print and digital sources; summarize or paraphrase information in notes and finished work, and provide a list of sources.
5.L.1:
Engage effectively in a range of collaborative discussions (one-on-one, in groups, and teacher-led) with diverse partners on grade 5 topics and texts, building on others’ ideas and expressing their own clearly,
Objective(s):
I can utilize the water cycle to build and test a device to produce freshwater from salted water.
Review of Previous Knowledge.
How can we separate mixtures?
What happens if we mix sand and iron filings?
Is this a physical or chemical change?
How can this be separated?
When we mix salt and water we get a solution. We cannot see the salt as it disappears in the water. If we taste this water, we will find that it is salty. Is it possible to take the salt out of the water?
Water Sources
Fresh water problems in the Western U.S.
The water cycle:
Saltwater Fun.
Reading
A cool glass of water can be very refreshing. Even though it may seem like there is an endless supply of water coming out of your faucet, it's important to remember that only 2.5% of the water in the world is freshwater!
Many people on Earth struggle to get a reliable supply of water, even if they live right next to an ocean. So if there is such a huge amount of ocean water on Earth, why can't we just drink it? Well, if you took a gulp of salt water, you would probably get sick because of the bad taste. Besides that, you would get even thirstier because your body cannot handle that much salt.
What if we could turn the salt water into fresh water? You may be surprised to hear, but many places are already doing it with a process called desalination. This process involves separating and removing high amounts of salt to get freshwater. There are places around the globe that perform this job, and they are called desalination plants. This newer technology just might be the future for our drinking water!
Nature has created its own way of removing salt from water: Fresh water is replenished through the process of the natural water cycle, in which water from seas, lakes, forests, land, rivers and reservoirs gets heated by the sun, the heat causes water to evaporate and form clouds, When the clouds become heavy, the water falls as rain or snow and returns inland as precipitation.
Questions/Agenda:
Gather: Discussion:
Where can we find salt water in abundance/nature?
How is sea water similar to the mixture/solution of salt and water?
Reason - Complete the reading.
If you were to drink seawater, what would happen?
Have you ever tasted rainwater? How does it taste?
How do we get rain water/What causes rain to fall?
How does the water cycle get the salt out of the water?
What is the role of the sun/atmosphere in the water cycle?
Design a device that mimics the water cycle to extract the salt from water.
Communicate:
Explain your device: what did you build? Did it work? How can it be improved?
Hands on Activity
Students form groups of 4.
Materials will be distributed.
Create a device that will take the salt out of water (using the water cycle as a guide).
(work time: 45 minutes)
Testing Time: Throughout the school day (very sunny day)
Students will check on the evaporation at regular intervals (approx 1 hour until the last hour of the day.�Students will create illustrations (using templates) with their observations.
Assessment
Test your device:
Did all the water evaporate? Were you able to collect the freshwater?
How did the freshwater taste? (tasting will be done by teacher or another adult).
If yes, what happened to the salt?
Illustrate and label your device.
If your water did not evaporate, explain what happened, and what changes can be made so that it works better.
ELA Assessment
Explain the similarities between your device and the water cycle.
How is it different?
Describe in detail how you built your desalination device, and what it accomplished.
Differentiation
Students will complete a prepared template using chronological order words, and sentence stems to explain the process.
They will illustrate and use content vocabulary from a word bank.
Students can build their still based on an image or diagram
Student
Remediation
Extension/Enrichment
Students will investigate other ways in which water can be desalinated.
Students create a report on how desalination can solve water problems in Arizona - in doing so, they will also discuss where they will source the sea/salt water to be desalinated.