Yes, heat, gas production or bubble formation and the color change are the signs of a chemical change.
The visible constellations<span> are definitely different
between the Northern and Southern Hemispheres. In general, at any given point
on Earth, only around 50% of the sky will be visible. We can understand this by
considering the atmosphere as a sphere around the earth. The sky any person can
view at one point can be compared to a giant dome equal to half of the sphere.
And because the Earth rotates, the dome we can see changes, unless one is
sitting directly on the North or South Pole.</span>
