Unit 7. Earth Science: Astronomy . Bell Ringer Activity: Get out a clean sheet of paper.
Everything formed in the same place at the same time: ~4.5 billion years ago.
Solar system was formed in the gravitational collapse of a giant cloud of gas and dust, known as the solar nebula.
The Solar System is thought to have started out as a giant gas cloud, composed mainly of hydrogen and helium, but also containing some heavier elements including ice and metals.
Under its own gravitational attraction, it collapses.
As a gas cloud collapses, it begins to spin more quickly.
The centrifugal force of this rotation flattens it out into a rotating disk with a protostar at the center.
The nebula is hot because of gravitational energy released by the collapse, and when the protostar ignites at the centre it produces more heat. So there is a strong temperature gradient across the disk: the temperature gets hotter towards the center.
C. Precession – the slow change in the direction of Earth’s axis of rotation. One cycle takes approx. 26,000 years. This does not change the seasons.
b. Autumnal Equinox – the Sun is going South around Sept. 23 = Fall.
2. The gravitational pull of the Moon and inertial force (outward directed force) cause tides.
5. Neap tide – During the moon's quarter phases the Sun and Moon work at right angles, causing the bulges to cancel each other. The result is a smaller difference between high and low tides. Neap tides are especially weak tides. They occur when the gravitational forces of the Moon and the Sun are perpendicular to one another (with respect to the Earth). Neap tides occur during quarter moons.
Nuclear power plants and nuclear bombs are examples of fission.
2. Nuclear Fusion – the combining of 2 or more nuclei into a larger nucleus.
2) Earth rotates on its axis (rapidly)
b. Photosynthesis – the changing of the Sun’s energy into stored chemical energy.
C6H12O6 + 6O2
Light + Water + Carbon glucose + oxygen
Plants and algae, which use photosynthesis, form the basis of the food chain.