Worksheet Grade 5 Science
Where Wardlow Valley Keeps Its Water: A Grade 5 Worksheet
Students graph Earth's salt and fresh water using a 100-cup model, then read a table of Wardlow Valley's reservoir, aquifer, and creek to compare stored water.
Objectives
- Students will graph the share of Earth's water that is ocean, ice, and other water.
- Students will compare the amounts of water held in a reservoir, an aquifer, and a creek.
- Students will explain how keeping ground unpaved helps refill an aquifer.
Vocabulary
- Aquifer
- An aquifer is an underground layer of rock, sand, or gravel that holds water in the tiny spaces between its grains. Wells reach down into aquifers to bring water up to the surface.
- Reservoir
- A human-made lake, usually created by a dam, that stores water for later. Reservoirs supply cities and farms and help control floods.
- Fresh water
- Fresh water is water with very little salt in it, the kind found in most rivers, lakes, and groundwater, and the kind people and land animals need to drink. It is different from the salty water that fills the oceans.
- Recharge
- Recharge is water soaking down through the ground to refill an aquifer, the way rain refills an underground sponge. Aquifers stay healthy only if recharge keeps up with pumping.
Also: salt water
Teacher overview
This worksheet moves from the whole planet down to one small place. Students begin with a 100-cup model of all the water on Earth, graph how little of it is fresh and reachable, and then read a table of the three places the fictional Wardlow Valley keeps its own water: a reservoir, a gravel aquifer, and a creek. A common error with the 100-cup model is counting the 2 frozen cups as water a town could use, which makes the fresh-water share look several times larger than it is. Items 2 and 4 separate stored ice from the water a community can actually pump, and the Wardlow table then shows what that small share looks like in one valley.
Student Worksheet
A class fills 100 cups. All 100 cups together stand for every drop of water on Earth.
- About 97 of every 100 parts of Earth's water is salty ocean water. How many of the 100 cups stand for ocean water?
- About 2 of the 100 cups stand for water frozen in ice caps and glaciers. The ocean cups and the frozen cups are set aside. How many cups are left for all the other water on Earth?
- Draw a bar graph with three bars: ocean water, frozen water, and all other water. Use the numbers 97, 2, and 1. Label each bar with its name and its number of cups.
- Look at the bar graph you drew. Explain why the bar for all other water is so short.
The town of Wardlow sits in a valley. Here is where Wardlow keeps its water.
| Where the water is | How much water |
|---|---|
| Wardlow Reservoir | 480,000 gallons held |
| Gravel aquifer under the valley | 1,200,000 gallons held |
| Wardlow Creek | 65,000 gallons flow past the town each day |
- Wardlow Reservoir holds 480,000 gallons. The gravel aquifer holds 1,200,000 gallons. Which one holds more water?
- The aquifer holds 1,200,000 gallons and the reservoir holds 480,000 gallons. How many more gallons does the aquifer hold?
- Wardlow uses 60,000 gallons of water each day. If the town used only the 480,000 gallons in the reservoir, how many days would that water last?
- Wardlow Creek carries 65,000 gallons past the town each day. Is that water stored in one place, or is it moving through? Explain your answer in one sentence.
- None of Wardlow's three water sources is salty. Use your answers from items 1 and 2 to explain why fresh water like this is worth taking care of.
- Wardlow does not let anyone pave the grassy field above the gravel aquifer. Rain soaks through that field and sinks down to the aquifer, which the town calls recharge. Explain how the rule about paving helps keep the aquifer full.
From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.
Answer Key
- Answer: 97 cups. The ocean holds about 97 of every 100 parts of Earth's water, so 97 of the 100 cups stand for ocean water.
- Answer: 1 cup. Set aside 97 ocean cups and 2 frozen cups: 97 plus 2 is 99, and 100 minus 99 leaves 1 cup for all other water.
- Answer: A bar graph with three labeled bars, one tall bar at 97 cups for ocean water, one very short bar at 2 cups for frozen water, and one very short bar at 1 cup for all other water. Accept any graph with the three bars drawn to scale and labeled.
- Answer: Almost all of Earth's water is already in the ocean or locked up as ice, so only about 1 cup out of 100 is left for rivers, lakes, and groundwater together.
- Answer: The gravel aquifer. It holds 1,200,000 gallons, which is more than the reservoir's 480,000 gallons.
- Answer: 720,000 gallons. Subtract to compare: 1,200,000 minus 480,000 equals 720,000 gallons.
- Answer: 8 days. Divide the stored water by the daily use: 480,000 divided by 60,000 equals 8 days.
- Answer: Moving through. The 65,000 gallons is a flow that passes the town each day and keeps going downstream, unlike the reservoir and the aquifer, which hold their water in one place.
- Answer: Only about 1 cup in 100 of Earth's water is fresh and reachable, so a valley with three fresh sources has a small share of something rare. Accept any answer that connects the small fresh-water share to the value of Wardlow's supply.
- Answer: Pavement would send rain running off the surface instead of soaking down. Leaving the field grassy lets rain sink through the soil and gravel and refill the aquifer below.
Differentiation
Support
Give these students a blank bar-graph grid with the vertical scale already numbered by tens and the three bar labels printed under the axis. For items 6 and 7, provide the subtraction and division set up with the numbers already placed, so the student supplies only the answer.
Extension
Ask these students to add a fourth bar to their graph showing what 1 cup would look like if it were split between the water in the ground and the water in rivers and lakes, and to write two sentences about which of Wardlow's sources would be hardest to replace if it ran dry.
ELL supports
Provide picture cards for "aquifer," "reservoir," and "creek," each with a simple cross-section sketch showing where the water sits. Allow students to answer items 4, 8, 9, and 10 with a labeled drawing plus a short phrase rather than a full sentence.
Extensions
Have students find out where their own community's drinking water is kept before it reaches the tap, using a utility website or a printed water quality report the teacher supplies, then add that source to a class version of the Wardlow table.