Ahava~Love Assembly

Grade 2 Science Week 11 | Teacher Guide

Grade 2 | SCIENCE

WEEK 11 • TEACHER GUIDE AND ANSWER KEY • DAYS 51–55

Read each lesson aloud with the child and model the worked example before practice. Do not show this key during practice. Accept oral, drawn or written answers where the child cannot yet write the whole answer. On Day 55, read aloud if needed but give no hints.

Week 11 Student Textbook | Week 11 Practice Workbook | Week 11 Teacher Guide | Week 10 Student Textbook | Week 12 Student Textbook | Grade 2 index

Day 51: Earth’s Surface Changes

Standard: Grade 2 Science Standard 10, 2.10

Practice record: Changes to the land, printed on the Week 11 Practice Workbook.

Worked example: A river carries sand from a hill down to a lake. Is this weathering or erosion? Worked answer: Erosion.

  1. Heavy rain.
  2. A rock cracks into pieces.
  3. Example: Soil washing off a hill moves soil to a new place, so it is erosion. A rock cracking breaks the rock but does not move it, so it is weathering. Accept any correct choice with a reason about moving or breaking.

Teaching note: Look outside for signs of erosion: bare soil after rain, sand at the bottom of a slope, or a gully in the yard.

Day 52: Slow Changes

Standard: Grade 2 Science Standard 10, 2.10

Practice record: Riverbank measurements, printed on the Week 11 Practice Workbook.

Worked example: A path in a park wears down a little more each year as people walk on it. Is this a slow change or a fast change? Worked answer: A slow change.

  1. 3 feet (20 – 17 = 3).
  2. 1 foot each year.
  3. The distance gets shorter by only 1 foot each year. A visitor on one day would not see a change, but measurements over four years show it. Accept any answer that uses the small yearly change as evidence.

Teaching note: The riverbank table is a teaching model, not a real place. Compare two photos of the same place taken years apart if you have them, such as an old family photo of a yard or a beach.

Day 53: Fast Changes

Standard: Grade 2 Science Standard 10, 2.10

Practice record: How long each event takes, printed on the Week 11 Practice Workbook.

Worked example: A storm drops so much rain in one night that a creek overflows and carves a new ditch. Is this a slow change or a fast change? Worked answer: A fast change.

  1. Earthquake.
  2. A river carving a canyon (millions of years).
  3. The eruption changed the mountain in one day, and the top was lowered by about 1,300 feet. One day is a short time, like the fast events in the table. Accept any answer that uses the one-day timing as evidence.

Teaching note: Children may feel worried about earthquakes and volcanoes. Explain that scientists watch for warning signs and that families can make safety plans.

Day 54: Model Slow and Fast Changes

Standard: Grade 2 Science Standard 10, 2.10

Practice record: Sample results, printed on the Week 11 Practice Workbook.

Worked example: Why should both sand hills get 1 cup of water? Worked answer: So that only the speed of the water is different.

  1. 3 inches (6 – 3 = 3).
  2. Hill B, the fast water.
  3. A gentle rain is like the slow drip: it moves a little soil at a time. A flood is like the fast pour: it moves a lot of soil at once and cuts deep grooves. Accept any answer that matches slow water with gentle rain and fast water with a flood.

Teaching note: Results vary with the sand. Expect the fast pour to wear the hill down more. Use the observation checklist below.

Hands-on task observation checklist (Model slow and fast water on sand hills). Check each item you observe. Four or five items shows the child met the task goal; two or three means repeat the task with support.

  • ☐ Child built two hills of about the same size.
  • ☐ Child measured both hills before the test.
  • ☐ Child used the same amount of water on each hill.
  • ☐ Child measured both hills after the test and recorded the results.
  • ☐ Child used the measurements to explain which water changed the hill more.

Day 55: Independent Check: Slow and Fast Changes

Standard: Grade 2 Science Standard 10, 2.10

Practice record: Two changes, printed on the Week 11 Practice Workbook.

Worked example: A beach loses a little sand each year to the waves. Is this a slow change or a fast change? Worked answer: A slow change.

  1. The landslide.
  2. Erosion (the sand is moved to a new place).
  3. Slow. The creek widened only 4 feet in 40 years, which is a very long time. Accept slow with the 40 years as evidence.

Teaching note: Independent check: read aloud if needed, but give no hints.

Sources

National Park Service, Grand Canyon: Geology (the Colorado River carved the canyon over millions of years) | U.S. Geological Survey, Mount St. Helens: From the 1980 Eruption to 2000 (summit lowered about 1,300 feet on May 18, 1980)

Week 11 Student Textbook | Week 11 Practice Workbook | Week 11 Teacher Guide | Week 10 Student Textbook | Week 12 Student Textbook | Grade 2 index