Day
A day is the period of time during which the Earth completes one rotation on its axis. This rotation takes approximately 24 hours, and it is the basis for our concept of time measurement. The Earth's rotation causes the cycle of day and night, as different parts of the planet are exposed to the Sun's light at different times.
Key Concepts
- Rotation: The Earth spins on its axis, causing day and night.
- 24 Hours: The approximate length of a full day on Earth.
- Day and Night: The cycle of light and darkness caused by the Earth's rotation.
Study Guide
.◂Science Worksheets and Study Guides Fourth Grade. Science in our world
Study Guide
Science in our world - 4th gr. 
Worksheet/Answer key
Science in our world - 4th gr. Worksheet/Answer key
Science in our world - 4th gr. Worksheet/Answer key
Science in our world - 4th gr. Vocabulary/Answer key
Science in our world - 4th gr.
Worksheet/Answer keyWorksheet/Answer keyWorksheet/Answer keyVocabulary/Answer keyThe resources above cover the following skills:
History and Nature of Science: A student should understand the history and nature of science. A student who meets the content standard should:
Develop an understanding that historical perspectives of scientific explanations demonstrate that scientific knowledge changes over time, building on prior knowledge.
Develop an understanding that scientific knowledge is ongoing and subject to change as new evidence becomes available through experimental and/or observational confirmation(s).