Seasons

Seasons

Objective

To describe what would happen to Maryland's climate if Earth wasn't tilted

Open Ended

Warm-up

What do you think would happen if Earth wasn't tilted?

What if….Earth Wasn’t Tilted?

When a Mars-size object collided with Earth 4.5 billion years ago, it knocked off a chunk that would become the moon. It also tilted Earth sideways a bit, so that our planet now orbits the sun on a slant of about 23.5 degrees. Those were two huge changes. Now, over the course of the year, the amount of sunlight striking the Northern and Southern hemispheres varies. This happens because sometimes the Earth’s axis is tilted towards the sun and on the other side of its orbit, it is tilted away. This causes uneven heating of the Earth’s surface and results in the seasons we have today.

Multiple Choice

Why is the Earth's axis tilted?

• Due to volcanoes

• Gravitation pull from the sun

• Collision with an object in space

Multiple Choice

What is the angle of Earth's tilt?

• 45 degrees

• 23.5 degrees

• 90 degrees

It's a lucky thing, too. Without Earth's tilt, humanity would be in a sorry state.

Forget modern technology, the steam engine, or sliced bread. In a world without seasons, there wouldn't even be wheat. According to Don Attwood, an anthropologist at McGill University in Montreal, humans would probably never have advanced past a state of living in small, scattered settlements, scrounging for survival and often dying of horrific insect-borne diseases.

Scientists think an Earth without a tilt would be separated into climate bands that would get increasingly colder as you moved away from the equator. The equator would receive all of the direct sunlight, increasing the temperature, while other regions receive more indirect sunlight. Humans would never survive the continuous winter of the high latitudes, and so we would likely migrate to more temperate areas nearer to the equator.

Multiple Select

Check all of the results of Earth not being tilted

• More disease

• Migration to warmer areas

• Less food/crops

• More seasons

When would we sleep?

The rotation of the Earth is responsible for day and night on our planet; however, the tilt of the axis has a major part to play in the length of day and night. Summer months tend to experience longer days as the Earth is tilted towards the sun, while winter days are shorter than its nights for the exact opposite reason. If Earth’s axis were upright, all areas would receive equal amounts of light every day resulting in a perfect 12 hours of day and 12 hours of night, an equinox!

Multiple Choice

How would night and day change if Earth wasn't tilted?

• It would always be night

• It would always be day

• Day and night would be 12 hours every day

Multiple Choice

Why does Earth have night and day at all?

• Because of its rotation

• Because of its revolution

• Because it has gravity

What's the forecast?

If the habitable world were a humid tropical zone like the rain forests of the Congo, unrelenting rainfall would quickly erode soil in any areas cleared for farming, and would leach nutrients down below root level, swiftly rendering tilled land infertile for crops.

On top of our problems with agriculture, humans would also be plagued by disease pathogens, which thrive in warm, humid environments. "Winter protects much of the world's population from tropical insects (which carry deadly diseases) and a long, nasty list of tropical diseases of humans, crops and livestock. 

Summary

Life on Earth would be drastically different without its tilt. Without it, we would no longer experience four seasons. In fact, we would be forever stuck in one season, plagued by disease, lack of crops, and smaller regions available for habitation. We should be grateful for the collision that shook our planet and tilted our axis millions of years ago.

Poll

Rate your understanding of today's objective: I can describe how Earth would change if it wasn't tilted.

• 4 - I got it! I could even explain it to someone else.

• 3- Makes sense to me!

• 2 -Kind of makes sense

• 1- Huh? I'm lost.

Formative Assessment GRADED

Using the information you've learned about seasons this week, complete the graded Seasons Exit Slip. You have 2 attempts.