Changes on the Earth
5 min
Narrative
In this Warm-up, students examine satellite images that show how the size of the Aral Sea has changed over time. This prepares them for later in the lesson when they will calculate percentages that represent the situation.
Launch
Arrange students in groups of 2. Introduce the context of satellite images of a body of water. Use Co-Craft Questions to orient students to the context and elicit possible mathematical questions.
Give students 1–2 minutes to write a list of mathematical questions that could be asked about the situation before comparing questions with a partner.
Student Task
1977
2006
2019
Sample Response
- If you wanted to create a scale drawing of this lake on a piece of 8.5-by-11-inch paper, what scale could you use?
- Estimate the area of the lake in 1977.
- Was the middle photo taken closer in time to the first photo or the last photo? By how many years?
- By what percentage did the area of the lake decrease from 1977 to 2006?
- By what percentage did the area of the lake decrease from 1977 to 2019?
Activity Synthesis (Teacher Notes)
Invite several partners to share one question with the class and record responses. Ask the class to make comparisons among the shared questions and their own. Ask, “What do these questions have in common? How are they different?” Listen for and amplify language related to the learning goal, such as “area,” “percent increase,” and “percent decrease”.
Explain that these are satellite photos of the Aral Sea, in central Asia. The amount of water in the sea has been decreasing since the 1960s when two rivers, the Syr Darya and the Amu Darya, were diverted to irrigate land to grow cotton and other crops. The Aralkum Desert is taking over the land where the Aral Sea used to be. Invite students to brainstorm how these changes may be affecting the people that live in this region.
Standards
- 7.RP.3·Use proportional relationships to solve multistep ratio and percent problems.
- 7.RP.A.3·Use proportional relationships to solve multistep ratio and percent problems. <span>Examples: simple interest, tax, markups and markdowns, gratuities and commissions, fees, percent increase and decrease, percent error.</span>
20 min
Knowledge Components
All skills for this lesson
No KCs tagged for this lesson
Changes on the Earth
5 min
Narrative
In this Warm-up, students examine satellite images that show how the size of the Aral Sea has changed over time. This prepares them for later in the lesson when they will calculate percentages that represent the situation.
Launch
Arrange students in groups of 2. Introduce the context of satellite images of a body of water. Use Co-Craft Questions to orient students to the context and elicit possible mathematical questions.
Give students 1–2 minutes to write a list of mathematical questions that could be asked about the situation before comparing questions with a partner.
Student Task
1977
2006
2019
Sample Response
- If you wanted to create a scale drawing of this lake on a piece of 8.5-by-11-inch paper, what scale could you use?
- Estimate the area of the lake in 1977.
- Was the middle photo taken closer in time to the first photo or the last photo? By how many years?
- By what percentage did the area of the lake decrease from 1977 to 2006?
- By what percentage did the area of the lake decrease from 1977 to 2019?
Activity Synthesis (Teacher Notes)
Invite several partners to share one question with the class and record responses. Ask the class to make comparisons among the shared questions and their own. Ask, “What do these questions have in common? How are they different?” Listen for and amplify language related to the learning goal, such as “area,” “percent increase,” and “percent decrease”.
Explain that these are satellite photos of the Aral Sea, in central Asia. The amount of water in the sea has been decreasing since the 1960s when two rivers, the Syr Darya and the Amu Darya, were diverted to irrigate land to grow cotton and other crops. The Aralkum Desert is taking over the land where the Aral Sea used to be. Invite students to brainstorm how these changes may be affecting the people that live in this region.
Standards
- 7.RP.3·Use proportional relationships to solve multistep ratio and percent problems.
- 7.RP.A.3·Use proportional relationships to solve multistep ratio and percent problems. <span>Examples: simple interest, tax, markups and markdowns, gratuities and commissions, fees, percent increase and decrease, percent error.</span>