Teaching overview
Learning points
- Lake Mead is a human-made reservoir in the Mojave Desert that provides Las Vegas with 90% of its fresh water. It was created as a result of the Hoover Dam's construction.
- The water in Lake Mead comes from the Colorado River. It is treated so it is safe to use by people in the surrounding area.
- The level of water in Lake Mead has been decreasing for decades, and is currently at an all-time low. As a result, Las Vegas has strict rules in place in order to reduce water usage.
Curriculum keywords
- Natural resources
- Recycling
- Climate change
- STEM
Multimedia toolbox
Water treatment video loop
Play the video loop as the students come in and sit down. Ask them to think about why we might need to reuse water.
Water use visual
Show the visual to the students before the video and ask them to think about what other uses we have for water. Tell them to create a mindmap showing this information.
Conservation
In natural resources, the management of that resource to preserve it and stop it from being wasted.
Conservation
Show the visual after the video to reinforce scientific terminology.
Bathtub ring visual
Show this visual to the students to spark a discussion about what might have caused the coloration. Do they think it is man-made? Or that it might have been caused naturally?
Spark a discussion
- Where does water come from?
- Where is water found on Earth?
- Is all water safe to drink?
- Is there enough water available to everyone? Why or why not?
- Why do you think the world’s water supplies are running out?
- Why do we build reservoirs? Why would it be a good idea to build a reservoir close to a city?
- What impact does building reservoirs have on the environment?
- Why do you think the water level in Lake Mead is going down?
- What would happen if Lake Mead dried up?
- What is the city of Las Vegas doing to conserve water?
- Do you think people waste too much water?
- Do you think we can recycle all water?
- Can you think of any inventive ways of saving water?
- How could you use less water? Do you think that it would be hard to use less water than you do now?
Activities
Just how wasteful is a dripping faucet?
INVESTIGATE how much water a dripping faucet wastes
Other activity ideas
- WRITE a social media post to let people in Las Vegas know about a new method of water conservation.
- DESIGN an informational poster that lets people know how they can save water in their homes and yards.
- RESEARCH how much water is used in students’ family homes each day – how much water is used in a toilet flush or a five-minute shower?
- CLASSIFY the students’ everyday uses of water as recreational vs. essential.
- DRAW an annotated picture showing how the water moves from the Colorado river to Las Vegas and back again to be recycled.
Just how wasteful is a dripping faucet?
Duration: 30 minutes
Resources:
- Jug
- Measuring cylinder
- Stopwatch
- Calculator (optional)
Key Learning:
Students will understand that they can make small changes that will save a large amount of water.Activity instructions:
- Have a class discussion about water wastage. You can ask the following discussion questions:
- Can you think of any examples of water being wasted?
- Do you think that you or your family might waste water at home?
- Can you think of anywhere in the school that water wastage might happen?
- Tell the students that they are going to find out how much water a dripping faucet loses over the space of a week.
- Find dripping faucets around the school, leaking hose pipes, or anything similar. Note: If there are no leaking faucets around the school, students can simulate one by simply turning on a faucet a tiny amount until it drips regularly.
- Ask the students to use the jug to collect water lost from the faucet over a period of exactly one minute. Explain that they should record the amount of water collected.
- Tell the students to use their information to calculate how much water is lost over the space of an hour, then over the space of a full day, then over the space of a week. Encourage students that finish their calculations early to try to work out how much water would be lost over the space of a full year.
Background information
- Las Vegas is located in the hot, dry Mojave Desert, where the average precipitation is just 127 millimeters per year. An area is considered a desert if it gets less than 250 millimeters per year. During the summer months, temperatures in the desert have reached as high as 56.7ºC, the highest temperature ever recorded anywhere on Earth. The city is also known as an urban heat island, which is an urban area that is significantly hotter than its surrounding rural areas. Urban heat islands are caused by an abundance of man-made dark surfaces like roads and buildings, which absorb more solar radiation.
- The Hoover Dam was constructed in 1936 to provide water and hydroelectric power to the areas surrounding it. The dam was built to control the flow of the Colorado River, and this resulted in the formation of a huge reservoir of water known as Lake Mead.
- 90% of the water that supplies Las Vegas comes from Lake Mead. The controlled flow of water passes through 17 turbines, producing 4 billion kilowatt-hours of hydroelectric power annually. This is enough electricity for 1.3 million people to live on.
- In 1983, the surface of the lake was measured at more than 370 meters above sea level – but in 2016, this had dropped to 327 meters. This can be seen clearly by looking at the rocks surrounding Lake Mead. Any rock that was once submerged in water is colored white because of the water’s mineral content. The minerals deposited on the cliffs stay there as the water slowly drains away.
- To get from Lake Mead to some areas of Las Vegas, water must travel more than 80 kilometers. It must also climb over 750 meters vertically over the course of its journey.
- Outdoor water is lost through evaporation. So cars are washed at special car washing facilities, and swimming pools have to be covered.
- Las Vegas collects and recycles all of its indoor wastewater – water produced by households and businesses. The water is sent to treatment plants, where it is chemically treated before going through a fine filtration process to make sure that it is completely safe and ready to be used again.
- While recycling water can help delay the drought in Las Vegas, it’s important to take steps to address the causes of the shortage. One of the main causes is human-made climate change – the warming of the planet will lead to more and more areas suffering from water shortages.
Glossary
- Conservation
- In natural resources, the management of that resource to preserve it and stop it from being wasted.
- Reservoir
- A natural or artificial pond or lake used for the storage of water, often for domestic use.
- Desert
- A region in which there is very little rainfall or other precipitation.
Twig Science: A Complete Pre-K–8 Program for the NGSS
Immersive Investigations with High-Quality Multimedia
- Investigating, designing, building, and understanding phenomena
- Hands-on, digital, video, and print investigations
- Synchronous/asynchronous distance learning