The stage in the water cycle that returns water to Earth is precipitation. Depending on the weather conditions, the temperature on the Earth's surface and in the atmosphere, and the topography of the land will determine the amount and type of precipitation. Precipitation forms when the droplets in the clouds are too heavy and fall back to Earth. Rain will fall when both the atmosphere and surface temperatures are above freezing. Hail will form when there is a thunderstorm, the temperature in the atmosphere is below freezing, and the surface temperature is above freezing. Snow forms when the temperature is below freezing in the atmosphere and on the surface of Earth. Finally, sleet is formed when the temperature in the atmosphere is above freezing, and the surface temperature is below freezing.

The stage in the water cycle where water is heated by the Sun and turns to vapor is evaporation. The water absorbs heat from the Sun's rays and slowly releases it into the atmosphere. Water changes from a liquid state to a gaseous state (vapor) and returns to the atmosphere. The oceans of Earth are the largest collection of water so therefore the most evaporation and precipitation take place over the ocean. Water moves out of the oceans during the process of evaporation.

NASA provides some background on the Sun compared to other stars, "Of course, the star that appears the brightest to all of us on Earth is the Sun. Although it is a rather typical star, not all that different from many of the ones you see at night, we live so close to it that it outshines everything else. Even the next closest star is more than a quarter of a million times farther from Earth, so it is not surprising that the light from the Sun overwhelms that from other stars." Due to the Earth's close (in relative terms) proximity to the Sun, it appears brightest to use because it is closer than all other stars in the galaxy.

Gretel's claim is supported by the research from NASA that her teacher presented. The Sun appears to be the brightest star because it is closest to Earth. It does not appear brightest because its the hottest, largest, or the brightest in the galaxy. "We live so close to it that it outshines everything else." This is the reason the Sun looks so bright.

Data tables are a great way to organize and analyze information from an investigation or experiment. In this investigation, a series of time-lapsed photos were taken from 6:00 am until 8:00 pm, and students measured the length of the shadow that a 1-meter long stick created as well as the angle of the shadow. When reviewing the data, a pattern was revealed about the length of the shadow. The length of the shadow decreased throughout the day until it reached its shortest measurement at the Sun's peak. The length of the shadows increased after this peak. Looking at the column labeled "length," the measurements are increasing until the Sun reaches its peak during the 1:00 pm hour. After the Sun is no longer at its highest point, the length of the shadow begins to increase again. The angle of the shadows also decreased throughout the day. Analyzing data can often lead to patterns being recognized, and predictions about future measurements can be made.

The Earth completes its orbit around the Sun or its revolution in about 365 days total. As the Earth revolves around the Sun, the position of the Earth changes and this creates the different views of the night sky. Day and night are caused by the Earth's rotation or spin on its axis. This rotation is what causes daylight and nighttime. As the Earth changes its position, the stars appear to move in the sky as well. The stars are stationary but seem to move in the sky. Each day the Earth travels further in its orbit, and a different part of the night sky is visible. The stars appear seasonally, so the pattern will remain the same but seem to move across the sky.

The part of Earth facing the Sun will experience day time. The opposite side will be experiencing nighttime. The Earth's rotation on its axis determines daytime and night because of its location regarding the Sun.

The Victoria State Education and Training department explains why this is true, "The Earth is one of several planets that orbit the Sun, and the moon orbits the Earth. The Earth is essentially a sphere, and the Sun is a nearby star, which is an unimaginably large ball of gas that radiates light and heat as products of nuclear reactions. The Earth orbits the Sun once every 365 days and rotates about its axis once every 24 hours. Day and night are due to the Earth rotating on its axis, not its orbit around the Sun. The term 'one day' is determined by the time the Earth takes to rotate once on its axis and includes both day time and night time."

Source: https://www.education.vic.gov.au/school/teachers/teachingresources/discipline/science/continuum/Pages/daynight.aspx

The amount of sunlight changes at a location based on whether they are facing towards the Sun or away from the Sun. When facing directly towards the Sun, an area will experience daytime while the opposite side of Earth experiences night. The light starts to dim as the Earth rotates, and the location begins to experience nighttime. As the rotation takes place, the opposite of Earth becomes lighter as daytime begins.

Four spheres are all independent parts of a system. The spheres interact with each other, and a change in one area can cause a change in another. Plants (biosphere) draw water (hydrosphere) and nutrients from the soil and release water vapor into the atmosphere. The biosphere contains all the planet's living things. This sphere includes all of the microorganisms, plants, and animals of Earth. The hydrosphere contains all the water of the planet, which exists in solid, liquid, and gas forms.

The Lithosphere- contains all of the solid land of the planet's crust, the semi-solid land underneath the crust, and even the molten part of Earth’s core.

The Hydrosphere- contains all the water of the planet, which exists in solid, liquid, and gas forms. Water flows as precipitation from the atmosphere down to Earth's surface, as rivers and streams along Earth's surface, and as groundwater beneath Earth's surface. Most of Earth's freshwater, however, is frozen.

The Biosphere - contains all the planet's living things. This sphere includes all of the microorganisms, plants, and animals of Earth. Within the biosphere, living things form ecological communities based on the physical surroundings of an area. These communities are referred to as biomes. Deserts, grasslands, and tropical rainforests are three of the many types of biomes that exist within the biosphere.

The Atmosphere-contains all the air in Earth's system. The upper portion of the atmosphere protects the organisms of the biosphere from the sun's ultraviolet radiation. It also absorbs and emits heat. This sphere is also where weather occurs.

Most Earth events involve interaction between multiple spheres. For example, rain is the movement of water (the hydrosphere) from the atmosphere to the lithosphere where it collects in lakes, rivers, or streams. Water is an important resource for inhabitants of the biosphere.