# Tidal Forces (DD-544)

> The Moon's gravity pulls the ocean into a bulge on the side facing it, and a second bulge forms on the far side because the Moon pulls Earth's center more strongly than the far ocean. As Earth rotates through both bulges, most coasts see two high and two low tides in about 24 hours and 50 minutes, a lunar day. The Sun's gravity adds smaller tides. The footage, credited to explainingtheuniverse, shows an animation of Earth's tidal bulges.

- Department: Science (also Space)
- First published: 2025-04-15
- Last updated: 2025-04-15
- Permalink: https://detailenjoyer.com/case/tidal-forces/
- Author: Marcus Easterling (DetailEnjoyer), The Detail Department

## Quick facts

- **DD-544-F01**: Moon's gravity. _(Write-up · Exhibit A (Cause))_
- **DD-544-F02**: Two. _(Write-up · Exhibit B (Bulges))_

## Write-up

The Moon raises ocean bulges on both sides of Earth. Most coasts get two high tides a day.

1. **Cause**: Moon's gravity.
2. **Bulges**: Two.
3. **Cycle**: About 24 h 50 min.
4. **Lows**: At 90 degrees.
5. **Sun**: Smaller effect.

## Related case files

- [It IS Rocket Science (DD-257)](https://detailenjoyer.com/case/it-is-rocket-science/): I linked more Earth

## Reel vs. record

- **Note**: The Reel attributes the far bulge to inertia and gives 'roughly every 24 hours'; the far bulge comes from the difference in the Moon's pull, and the cycle is about 24 hours 50 minutes.

## Video: Tidal Forces: The Moon Raises Ocean Bulges on Both Sides of Earth

- Duration: 21.2 s · Published: 2025-04-15
- File: https://detailenjoyer.com/assets/videos/DIeSwCqxB9j.mp4

### Transcript

Did you know, the moon affects Earth's tides through its gravitational pull, which causes the oceans to bulge slightly on the side facing the moon, and also on the opposite side due to inertia. These bulges create high tides, while the areas at 90 degrees to the moon experience low tides. As the Earth rotates, different coastal regions pass through these bulges, resulting in two high tides and two low tides roughly every 24 hours. NOW YOU KNOW!

## Questions & answers

**Q: How many bulges?**  
A: Both sides. _(Source: Write-up · Exhibit A (Cause) · Wikipedia: Tide)_

**Q: Tidal day?**  
A: Lunar. _(Source: Write-up · Exhibit B (Bulges) · Wikipedia: Tide)_

**Q: Main cause?**  
A: Pull. _(Source: Write-up · Exhibit C (Cycle) · Wikipedia: Tide)_

**Q: Low tides occur?**  
A: Between. _(Source: Write-up · Exhibit D (Lows) · Wikipedia: Tide)_

**Q: Also contributes?**  
A: Smaller. _(Source: Write-up · Exhibit E (Sun) · Wikipedia: Tide)_

## Sources

- [Wikipedia: Tide](https://en.wikipedia.org/wiki/Tide)

## Cite this case file

Easterling, Marcus. "Tidal Forces." The Detail Department (DetailEnjoyer), case file DD-544, last updated Apr 15, 2025. https://detailenjoyer.com/case/tidal-forces/