Why are temperatures cooler in the
northern hemisphere at this time?

Earth spins on an angle, so the Northern hemisphere is towards the sun in the summer, making it warmer and having the temperature increase, so the opposite of that is that in the winter, the Northern Hemisphere tilts away from the sun, making the temperatures decrease.

Hope this helps!

Explanation:

I give you the word equation first and then the chemical equation.

Water + electricity = Hydrogen + Oxygen

What that means is that if you have same sort of mineral that won't separate with the electricity put in the water, then you get the water "breaking down" into oxygen and hydrogen.

2H2O ===> 2H2 + O2

At this stage you don't have to worry about what the 2 in front of the hydrogen and the 2 in front of the water means. One of the properties of water is that it is hard to get the water molecule to break down.  Not impossible. Just hard.