Seasonal Temperatures and Water Cycles

In this lesson, students analyze graphs to connect seasonal temperatures with the amount of daylight over a year. Students then conduct an experiment to test how heat affects how much water cycles.

• All of Earth is warmed by heat from the sun, and Earth’s tilt affects how much sunlight reaches Earth. This affects the temperature of different places on Earth. Temperatures also depend on the season. Temperature is a measure of heat, and it is measured with a thermometer.
• There is a relationship between Earth’s position in space and temperatures on Earth.
• Each season has specific weather patterns. Weather is the conditions of the atmosphere in a particular place at a particular time. The atmosphere is the blanket of air that covers a planet.
• When the sun shines, it heats up all of Earth’s surface, including all of the water on Earth.
• Water is always moving around the planet, and that this movement is part of the water cycle.
• Scientists get knowledge about seasons and the water cycle, and all other scientific knowledge, from observations and experiments. Scientists follow a process as they conduct experiments, which helps guide scientists as they move from a question to a data-based conclusion.

• What would happen to temperatures on Earth if the sun didn’t shine?
• How can you tell that summer is ending and fall is beginning, or that winter is ending and spring is beginning?
• What makes summer the hottest season? What makes winter the coldest season?
• What is the relationship between the weather and the season?
• How do plants and animals act in a particular season?
• Where can water be found on Earth?
• What happens to water in the atmosphere?
• What happens to water once it falls back to Earth’s surface?
• Why is the water cycle a cycle? How does the water cycle support the idea that water is never “lost” or “created?
• How is an answer that uses data different from an answer based on opinion?
• Why is it helpful to follow the scientific process to answer questions?

Misconception: Seasons are caused by Earth’s distance from the sun—summer is warm because Earth is closer to the sun. Winter is cool because Earth is farther from the sun.

Fact: Seasons are caused by Earth’s tilt on its axis. Summer happens for the part of Earth tilted toward the sun. Winter happens for the part of Earth tilted away from the sun. The part of Earth experiencing winter is actually slightly closer to the sun than the part of Earth experiencing summer.

Misconception: Seasons are the same everywhere on Earth.

Fact: Different parts of the world experience different seasons. For example, near the equator there are just two seasons: a wet season and a dry season.

Atmosphere : the blanket of air that covers a planet

Collection : the process of liquid water being stored on Earth’s surface

Condensation: the process of water vapor changing into liquid water

Evaporation : the process of liquid water changing into water vapor, its gas state

Precipitation : Defining and Delimiting Engineering Problems

Season : Optimizing the Design Solution

Temperature : a measure of heat; measured with a thermometer

Water cycle :Optimizing the Design Solution

Weather : the conditions of the atmosphere in a particular place at a particular time; includes temperature and precipitation

The sun heats water on Earth. Some of the water in the oceans, rivers, and lakes turns into a gas. This gas moves into the atmosphere. We can’t see it, but it is still there. This is evaporation.

Evaporation is what happens when you leave a glass of water outside on a hot summer day. Over time, there will be less water in the glass. The water didn’t disappear. Heat turned some of that water into a gas in the air.

Over time, water in the atmosphere gets cooler. It turns back into a liquid. This is condensation. The drops of water attach to pieces of dirt or dust in the sky. Over time, many of these pieces join together. They form a cloud.

When the cloud gets too heavy, the liquid water falls back onto the surface. It can be either rain or snow. This is precipitation.

After it rains, the water is stored in lakes, rivers and oceans. This is collection. That water is again heated by the sun. Some of it will evaporate again. Water always moves around the planet. This movement is part of the water cycle. Evaporation, condensation, precipitation, and collection are steps of the water cycle.

In this lesson, students go through the scientific process and conduct an experiment to determine how the water cycle varies based on the amount of heat present. First, students come up with a question to explore regarding how heat affects the water cycle. Then, they develop a hypothesis to test in an experiment using simple materials. In the experiment, student teams collaboratively collect and analyze observational data about changes in the water within different containers after three days. Finally, they use the data to make a claim based on the evidence.