Lesson Notes By Weeks and Term v4 - SHS 3
BASIC PHYSICS
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BASIC PHYSICS
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Subject: Physics
Class: SHS 3
Term: 1st Term
Week: 8
Grade code: 3.1.1.LI.2
Strand code: 1
Sub-strand code: 1
Content standard code: 3.1.1.CS.3
Indicator code: 3.1.1.LI.2
Theme: MECHANICS AND MATTER
Subtheme: BASIC PHYSICS
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This lesson moves beyond the typical textbook physics of forces and equations to explore the "living physics" that has been practiced by our ancestors in Ghana for centuries. Before telescopes and satellites, our people looked to the skies—the sun, moon, and stars—to guide their lives. This indigenous knowledge of astronomy (the study of celestial objects) and cosmology (the study of the origin and nature of the universe) was essential for survival and culture. It informed when to plant crops, when to fish, how to navigate, and when to celebrate important festivals.
A. Defining Our Terms Astronomy: The scientific study of everything in the universe beyond Earth's atmosphere. This includes the sun, moon, planets, stars, galaxies, and the physical laws that govern them. *Indigenous Astronomy:* This is the specific knowledge of celestial bodies and their cycles developed and passed down through generations within a particular culture. It is practical and observational. For example, knowing that the appearance of a particular star cluster signals the start of the rainy season. Cosmology: A branch of astronomy that deals with the origin, evolution, and ultimate fate of the universe. It asks the "big questions": How did the universe begin? What is it made of? Where is it going? *Indigenous Cosmology:* This refers to the creation stories and belief systems of a culture that explain how the universe and humanity came to be. For example, the Akan story of Nyame (the Sky God) and Asase Yaa (the Earth Goddess). Indigenous Knowledge System (IKS): A body of knowledge, practices, and beliefs developed by local communities over generations through their interaction with their environment. It is often passed down orally and is vital for decision-making in areas like agriculture, health, and resource management. Our focus today is on the astronomical part of IKS. B. Applications of Astronomy in Ghanaian Indigenous Culture Agriculture: The Celestial Farming Calendar Before the Gregorian calendar was common, farmers relied on celestial cues to guide their planting and harvesting schedules. The Sun and Seasons: The most basic astronomical observation is the sun's path across the sky, which changes throughout the year. This change causes the seasons (rainy season, dry season/Harmattan). Our ancestors knew the position of the sun at sunrise and sunset could indicate the time of year. The Moon and Planting: The lunar cycle (the ~29.5 days it takes for the moon to go through all its phases) was used to time the planting of specific crops. Some communities believed planting certain vegetables during a new moon or full moon yielded better results. While the scientific link can be debated, it provided a consistent and reliable calendar. Stars as Harbingers of Rain: Many Ghanaian farming communities, particularly in the northern regions, watch for the appearance of the Pleiades star cluster (known as *“Miong”* in Dagbani or *“Asonomma”* in Twi) in the pre-dawn sky. Its visibility at a certain time of year signals that the main rainy season is approaching, and it is time to prepare the land for planting millet, sorghum, and yams. This is a highly accurate method developed over centuries of careful observation. Fishing: Riding the Moon's Tides For coastal communities like the Fante, Ewe, and Ga, the moon is not just a light in the night sky; it is a critical tool for their livelihood. The Moon's Gravitational Pull: As we know from physics, the moon's gravity pulls on Earth's oceans, causing tides. Spring Tides: When the Sun, Moon, and Earth are aligned (during a new moon and full moon), the gravitational pulls combine, leading to very high high-tides and very low low-tides. Neap Tides: When the Sun and Moon are at right angles to each other (during the first and third quarter moons), their gravitational pulls partially cancel out, leading to less extreme tides (lower high-tides and higher low-tides). Indigenous Application: Ghanaian fishermen have a deep, practical understanding of this. They know that fishing during spring tides can be more productive but also more dangerous due to strong currents. They use the moon's phase to predict the best and safest times to go to sea, when to cast their nets, and when to expect the fish to be running. This knowledge is passed from father to son and is essential for safety and economic success. Festivals and Timekeeping: The Lunar Calendar Many important traditional Ghanaian festivals are scheduled using a lunar calendar, not the 365-day Gregorian calendar we use in school and business. How a Lunar Calendar Works: A lunar month begins with the sighting of the new crescent moon. A lunar year consists of 12 of these months, which is about 354 days long—11 days shorter than a solar year. This is why the dates of these festivals shift each year on the standard calendar.