Why summer is hot
Concentrated sunlight and long days.
Two equal beams
Two equal beams of sunlight fall on the Earth. One falls almost straight. The other falls at a slant.
Which beam do you think heats the ground more?
What this lesson covers
The idea
The hemisphere tilted towards the Sun gets sunrays spread over a smaller area, so it is heated more, and also gets more than 12 hours of sunlight, giving summer; the hemisphere tilted away has winter with shorter daylight.
Two equal beams
Two equal beams of sunlight fall on the Earth. One falls almost straight. The other falls at a slant.
Which beam do you think heats the ground more?
- The one that falls almost straight
- The one that falls at a slant
- Both heat it equally
Patches of light
Look at June and at December. See how big each patch is.
Now look at the length of daytime. The view is from above the North Pole, and the ring is a circle of latitude.
More heat, more hours
The beam falling nearly straight lights a small patch, so that patch is heated more. The leaning hemisphere also has sunlight for more than 12 hours. That makes summer.
The hemisphere tilted towards the Sun gets sunrays spread over a smaller area, so it is heated more, and also gets more than 12 hours of sunlight, giving summer; the hemisphere tilted away has winter with shorter daylight.
Notes
The hemisphere tilted towards the Sun gets sunrays spread over a smaller area, so it is heated more, and also gets more than 12 hours of sunlight, giving summer; the hemisphere tilted away has winter with shorter daylight.
Check yourself
The hemisphere tilted towards the Sun has …
In summer the sunrays fall on …
In June, the Northern Hemisphere gets sunlight for …
Why does a place get hotter in summer?
- winter. The hemisphere tilted away from the Sun has winter.
- no seasons. Seasons happen all over the Earth, except they are weak near the equator.
- summer — correct. Yes! It gets more heat and longer days.
- a smaller area — correct. Yes! The same sunlight is packed into a small patch.
- a bigger area. A bigger area means the same sunlight is spread thin, as in winter.
- no area at all. Sunlight reaches the ground in both seasons.
- exactly 12 hours. Daytime is exactly 12 hours only around the equinoxes, in March and September.
- more than 12 hours — correct. Yes! The days are long in summer.
- less than 12 hours. Shorter daytime is for winter.
- The Earth comes much closer to the Sun. The distance is not the reason for seasons. The tilt is.
- The Sun becomes bigger. The Sun does not change in size through the year.
- The same sunlight is spread over a smaller area, and the day is longer — correct. Yes! Both things add up to more heat.