earth science

Marine Day

Marine Day is a earth science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Marine Day rather than just read about it. In short: Marine Day (Japanese: 海の日, Hepburn: Umi no Hi), also known as "Ocean Day" or "Sea Day", is a public holiday in Japan usually celebrated on the third Monday in July. The holiday is to give thanks to the ocean for its bounty and to consider the importance of it to Japan as a maritime nation.

Key takeaways

Marine Day belongs to earth science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Marine Day to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Marine Day from memory before moving on to harder problems.

Reference excerpt

Marine Day (Japanese: 海の日, Hepburn: Umi no Hi), also known as "Ocean Day" or "Sea Day", is a public holiday in Japan usually celebrated on the third Monday in July. The holiday is to give thanks to the ocean for its bounty and to consider the importance of it to Japan as a maritime nation. Many people take advantage of the holiday and summer weather to take a beach trip. Other ocean-related festivities are observed as well. The date roughly coincides with the end of the rainy season (梅雨 tsuyu) in much of the Japanese mainland. In 2020, the holiday was observed on Thursday, July 23, a one-time move that was made as a special accommodation to support the opening of the Tokyo Olympics. Due to the postponement of the Olympics, the 2021 date was moved to July 22, also on Thursday as a one-time move.

History

The day was known as Marine Memorial Day (海の記念日, umi no kinen bi) until 1996. Communications Minister Shōzō Murata designated the day in 1941 to commemorate the Meiji Emperor and his 1876 voyage in the Meiji Maru, an iron steamship constructed in Scotland in 1874. The voyage included a trip around the Tōhoku region, embarking on a lighthouse boat in Aomori, and a brief stop in Hakodate before returning to Yokohama on July 20 of that year. However, it was not designated a national holiday until 1995, when it became the first holiday in the summer months. First observed on July 20, 1996, the Happy Monday System legislation moved the date to the third Monday of July beginning in 2003. As special arrangement for the 2020 Summer Olympics, the 2020 date for Marine Day was moved to July 23. With the Olympics and Paralympics postponed until 2021 due to the COVID-19 pandemic, the government left this change in place for 2020 and passed an amendment to the Olympic and Paralympic Special Measures Act to make a corresponding change to the holiday in 2021.

Celebration On this day, families may visit beaches such as Isshiki Beach in Hayama and swim, snorkel, surf, or dive. People may also participate in an event called 'mud-ball throwing'. National aquariums also host special water-related events on this day.

References

External links Book entry about the Meiji Maru Marine Day Celebration

Illustrations

Worked examples

Example 1 — a first encounter with Marine Day

Start with the simplest possible case. Write down what Marine Day claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In earth science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Marine Day before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Marine Day ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Marine Day

In research: Marine Day appears in earth science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Marine Day in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Marine Day is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1995 establishments in Japan, Environmental awareness days, July observances, so understanding it makes those chapters shorter.
In everyday life: Look for Marine Day outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Marine Day in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Marine Day means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Marine Day out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Marine Day in simple terms?

Why does Marine Day matter?

Because it connects several earth science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Marine Day?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Marine Day.