Kaupapa: 15 / 08 Tuesday Describe how the Sun produces its energy Describe why we need the Sun to stay alive

Do you remember? Why are there more craters on the moon than on the earth? Why is the moon phases cycle 29.5 days long if it takes only 27.3 days to orbit the earth once?

What am I? I’m a star! I am just a ball of gas. But I give lots of energy. Plants turn my energy into food. My gravity is 28 times stronger. I am very hot – 5500 oC just on the surface. I am very big – more than 100 timers larger than Earth. I am the centre of the solar system.

SUN

What colour is the sun?

Why is the sky blue?

Why is the sky red at sunrise and sunset?

Without the Sun, none of us will be alive now… Why?

“Photosynthesis!”

How does the Sun make its energy?

E = mc2

Hydrogen-3 (Tritium) Hydrogen-2 (Deuterium)

“Fusion” Helium Neutron

“Fusion” 31H + 21H → 42He + 10n

Will the sun last forever?

The Sun The Sun is a star and is mostly made of two elements – hydrogen and helium. The Sun makes its energy from nuclear reactions (hydrogen atoms combine into helium atoms). The Sun is the ultimate source of energy needed to sustain life on earth.

Solar System

Mercury (58,000,000 km)

Venus (107,000,000 km)

Earth (147,000,000 km)

Mars (205,000,000 km)

Jupiter (741,000,000 km)

Saturn (1,350,000,000 km)

Uranus (2,750,000,000 km)

Neptune (4,450,000,000 km)

Pluto (7,400,000,000 km, average)

At the center of your area, mark a place and label it: "THE SUN" Measure out 20 cm and label that spot: "MERCURY" Now go 35 cm from the Sun and label it: "VENUS" Now go half a meter from the Sun and label it: "THE EARTH" 1 m from the Sun is "MARS" 3 m from the Sun is "JUPITER" 5 m from the Sun is "SATURN" 8 m from the Sun is "URANUS" 15 m from the Sun is "NEPTUNE" 20 m from the Sun is "PLUTO"

What have we learned today? The Sun is made of two elements: what are they? How does the sun produce its energy?