Grade Level: This website is more suited to the reasoning skills of upper elementary/ middle school students.
Objective: Measure 6 liters of water from a 5-liter jug and a 7-liter jug
Task: Fill-up the jars and use them to measure 6 liters of water. The jugs can be emptied, refilled, and transferred to the other container multiple times until the goal is achieved.
For example, if you fill up the 5-liter jug and then pour it into the 7-liter jug, you can refill the 5-liter jug and pour it into the 7-liter jug leaving 3 liters in the 5-liter jug. You’ve just measured 3 liters.
Students will need to make moves like the one above to measure 6 liters.
Note: This is a challenging task, but it is possible. I’ve had students master this task in the past!
Ways to Utilize the Activity: This website is a great way to get your student thinking about how to solve problems such as these. Consider displaying the website to the class and review the directions. Then, as a class, discuss ways to approach the task. Ask questions such as:
- What is the task asking us to do?
- What special conditions do we need to consider?
- How can we measure different amounts, other than 5 liters or 7 liters, using these two jugs? Let’s try to measure 3 liters.
- What’s the purpose of being able to fill the jug and transfer it to the other jug?
You may also want to consider allowing students to work in pairs to approach the task and discuss ways to meet the goal together.
This applet makes a great fast finisher activity. It can also be included on a math menu or used on a menu of problem solving station options.
Variations: This activity can be simulated in the classroom with actual jugs of water. Set the situation up by saying that you need to measure ____ liters of water but you only have a ____-liter jug and a ____-liter jug. Try using this model to support the students’ understanding of the task before using the website for struggling students or younger students.