Writing prompt w05: two sentences on why the sky is blue, answered by fifteen AI models
Prompt w05 (two-sentence) was answered 3 times by each of 15 models. This page lists every output, the rater's rubric scores and whether each output passed the format rule (exactly 2 sentences). Best mean rubric score on this prompt: Llama 3.2 3B.
Tested by us on 2026-10-26 (America/Chicago): open-weight models run locally on a CPU-only machine, outputs rated by a separate model (Mistral 7B Instruct v0.3) that is not a writer in this test. Indicative results, not a benchmark, and not a statement about any vendor's hosted models.
Summary
In exactly two sentences, explain why the sky is blue.Format rule checked by code: exactly 2 sentences.
| Model | Mean rubric score (1 to 5) | Format rule passed |
|---|---|---|
| Llama 3.2 1B | 4.73 | 3 of 3 |
| Phi-3.5 mini | 4.33 | 3 of 3 |
| Llama 3.2 3B | 4.80 | 3 of 3 |
| Gemma 2 2B | 4.40 | 3 of 3 |
| Gemma 3 1B | 4.47 | 3 of 3 |
| SmolLM2 1.7B | 4.27 | 1 of 3 |
| Qwen2.5 7B | 4.67 | 3 of 3 |
| Qwen2.5 3B | 4.53 | 0 of 3 |
| Qwen2.5 1.5B | 4.47 | 2 of 3 |
| Qwen3 0.6B (non-thinking) | 4.27 | 0 of 3 |
| Qwen2.5 0.5B | 4.27 | 0 of 3 |
| Falcon3 3B | 4.40 | 0 of 3 |
| Granite 3.3 2B | 4.20 | 3 of 3 |
| Qwen3 1.7B (non-thinking) | 4.60 | 3 of 3 |
| TinyLlama 1.1B Chat | 4.13 | 0 of 3 |
Llama 3.2 1B: all 3 outputs
The sky appears blue due to a phenomenon called Rayleigh scattering, where shorter wavelengths of light, such as blue and violet, are scattered more than longer wavelengths, like red and orange, by the tiny molecules of gases in the atmosphere. This scattering effect is more pronounced when the sun is overhead, causing the blue light to be dispersed throughout the atmosphere, giving the sky its characteristic blue color.The sky appears blue due to a phenomenon called Rayleigh scattering, in which shorter, blue wavelengths of light are scattered more than longer wavelengths (like red and orange) by the tiny molecules of gases in the atmosphere. This scattering effect is a result of the atoms and molecules in the atmosphere having a greater tendency to absorb and scatter blue light than other wavelengths, leading to the blue color we see from the Earth's surface.The sky appears blue because of a phenomenon called Rayleigh scattering, in which shorter wavelengths of light, like blue and violet, are scattered more than longer wavelengths, like red and orange, by the tiny molecules of gases in the atmosphere. This scattering effect is more pronounced when the sun is overhead, which is why the sky typically appears blue during the daytime.Phi-3.5 mini: all 3 outputs
The sky appears blue due to the scattering of sunlight by molecules in the Earth's atmosphere, a phenomenon known as Rayleigh scattering, which causes shorter (blue) wavelengths to scatter more than longer (red) wavelengths. As a result, when we look up at the sky, we see more blue light than any other color.The sky appears blue due to Rayleigh scattering, where molecules and small particles in the Earth's atmosphere scatter sunlight in all directions, and blue light is scattered more than other colors because it travels in shorter, smaller waves. This effect is enhanced when the sun is high in the sky, making the blue color more prominent to our eyes.The sky appears blue to the human eye because molecules in Earth's atmosphere scatter sunlight in all directions and blue light is scattered more than other colors because it travels in shorter, smaller waves. This phenomenon is known as Rayleigh scattering.Llama 3.2 3B: all 3 outputs
The sky appears blue because of a phenomenon called Rayleigh scattering, where shorter wavelengths of light (such as blue and violet) are scattered more than longer wavelengths (like red and orange) by the tiny molecules of gases in the Earth's atmosphere. As a result, the blue light is dispersed throughout the atmosphere, reaching our eyes from all directions and giving the sky its blue color.The sky appears blue due to a phenomenon called Rayleigh scattering, where shorter wavelengths of light, such as blue and violet, are scattered more efficiently by the tiny molecules of gases in the atmosphere than longer wavelengths, like red and orange. This scattering effect gives the sky its blue color, with the color intensity varying depending on the time of day, atmospheric conditions, and other factors.The sky appears blue because of a phenomenon called Rayleigh scattering, in which shorter wavelengths of light (like blue and violet) scatter more than longer wavelengths (like red and orange) as they pass through the Earth's atmosphere. This scattering effect gives the sky its blue color, as the scattered blue light is then dispersed throughout the atmosphere, creating the blue hue we see.Gemma 2 2B: all 3 outputs
The sky appears blue due to a phenomenon called Rayleigh scattering. Sunlight is scattered by tiny molecules in the Earth's atmosphere, and blue light is scattered more effectively than other colors, making the sky appear blue to our eyes.The sky appears blue due to a phenomenon called Rayleigh scattering. This scattering occurs when sunlight interacts with the tiny molecules in Earth's atmosphere, causing blue light to be scattered more than other colors.Sunlight contains all colors of the rainbow, but the sky appears blue because blue light is scattered more by particles in the atmosphere than other colors. This scattering effect, called Rayleigh scattering, is stronger for shorter wavelengths like blue.Gemma 3 1B: all 3 outputs
The sky appears blue primarily due to a phenomenon called Rayleigh scattering, where shorter wavelengths of light – like blue – are scattered more by the molecules in the atmosphere than longer wavelengths. This scattering makes the sky appear blue to our eyes!The sky appears blue due to a phenomenon called Rayleigh scattering, where shorter wavelengths of light, like blue, are scattered more by the atmosphere than longer wavelengths. This scattering effect makes blue light more abundant in the sky, making it appear blue to our eyes.Sunlight is made up of all colors of the rainbow, but blue light is scattered more by the atmosphere than other colors. This scattering effect causes blue light to be dispersed throughout the sky, making it appear blue to our eyes.SmolLM2 1.7B: all 3 outputs
The sky appears blue because of a process called Rayleigh scattering, which occurs when sunlight interacts with the Earth's atmosphere. The shorter wavelengths of light, like blue and violet, are scattered more than the longer wavelengths, like red and orange.The sky appears blue because the Earth's atmosphere scatters sunlight in all directions and blue light is scattered more than other colors because it travels as shorter, smaller waves.The sky appears blue because of a process called Rayleigh scattering, where the shorter, blue wavelengths of light are scattered more than longer, red wavelengths by the tiny molecules of gases in the atmosphere.Qwen2.5 7B: all 3 outputs
The sky appears blue because the Earth's atmosphere scatters shorter wavelength blue light more than longer wavelength red light when sunlight passes through it. This scattering, known as Rayleigh scattering, makes the sky appear blue to an observer on the Earth's surface.The sky appears blue during the day because the Earth's atmosphere scatters short-wavelength light (like blue and violet) more than longer wavelength light (like red and orange). This scattering, known as Rayleigh scattering, makes the sky look blue to us.The sky appears blue because the Earth's atmosphere scatters short-wavelength light more than long-wavelength light, a phenomenon known as Rayleigh scattering. Blue light is scattered in all directions by the gases and particles in the atmosphere, making the sky appear blue to an observer on the surface.Qwen2.5 3B: all 3 outputs
The sky appears blue because the Earth's atmosphere scatters sunlight in all directions and preferentially scatters shorter blue wavelengths more than longer red wavelengths.The sky appears blue because the Earth's atmosphere scatters sunlight in all directions and predominantly scatters blue light, which has a shorter wavelength and is more easily scattered by air molecules.The sky appears blue because the Earth's atmosphere scatters sunlight in all directions and preferentially scatters blue light, which has a shorter wavelength, more effectively than red light.Qwen2.5 1.5B: all 3 outputs
The sky appears blue because the atmosphere scatters sunlight in all directions, with shorter blue wavelengths being scattered more than longer red wavelengths. This blue light is the only color that reaches our eyes when the sun is high in the sky.The sky appears blue because of a phenomenon called Rayleigh scattering. When sunlight passes through Earth's atmosphere, shorter wavelengths of light (like blue and violet) are scattered more by the air molecules, making the sky appear blue.The sky appears blue because shorter blue wavelengths of light are scattered more by the atmosphere than longer wavelengths, so the scattered blue light predominantly reaches our eyes.Qwen3 0.6B (non-thinking): all 3 outputs
The sky appears blue because of the scattering of sunlight by the Earth's atmosphere, which disperses blue light more efficiently than other colors.The sky appears blue because sunlight is scattered by the molecules in the atmosphere, causing light to be refracted and scattered in different wavelengths, with blue light being the dominant color.The sky appears blue because of Rayleigh scattering, where shorter wavelengths of sunlight (blue) are scattered more than longer wavelengths (red) by the atmosphere, making the sky appear predominantly blue.Qwen2.5 0.5B: all 3 outputs
The sky is generally blue because it reflects sunlight, which contains all colors of the visible spectrum, including blue.The sky is blue because of the scattering of sunlight by molecules in the Earth's atmosphere, especially nitrogen and oxygen, which scatter blue light more than other colors.The sky is blue because it reflects sunlight, which has a wavelength of about 480-520 nanometers and is absorbed by most other colors, leaving blue as the dominant color.Falcon3 3B: all 3 outputs
The sky appears blue due to a phenomenon called Rayleigh scattering, where sunlight is scattered in all directions by the Earth's atmosphere, more effectively by smaller particles and shorter wavelengths, like blue light.The sky appears blue due to a phenomenon called Rayleigh scattering, where sunlight interacts with the gases and particles in Earth's atmosphere, causing shorter wavelength blue light to be scattered more effectively than other colors, making the sky appear blue during the day.The sky appears blue due to a phenomenon called Rayleigh scattering, where sunlight interacts with molecules and tiny particles in Earth's atmosphere, causing shorter blue wavelengths to scatter more than other colors, making the sky appear blue during the day.Granite 3.3 2B: all 3 outputs
The sky appears blue due to a process called Rayleigh scattering, where shorter wavelengths (blue and violet) are scattered more than longer wavelengths (red, orange, yellow) because shorter waves travel in shorter, snappier paths. However, our eyes are more sensitive to blue light and violet light is not as visible to us, making the sky appear blue.The sky appears blue due to a process called Rayleigh scattering, where shorter wavelength light (blue and violet) is scattered more than longer wavelength light (red, orange, yellow) by Earth's atmosphere. However, our eyes are more sensitive to blue light, and sunlight reaches us more from the blue part of the spectrum, giving the sky its characteristic blue hue.The sky appears blue due to a phenomenon called Rayleigh scattering, where shorter-wavelength light (blue and violet) is scattered more than longer-wavelength light (red, orange, yellow) by Earth's atmosphere. However, we perceive the sky as blue, not violet, because our eyes are more sensitive to blue light and sunlight reaches us more abundantly in that color range.Qwen3 1.7B (non-thinking): all 3 outputs
The sky appears blue because sunlight is scattered by the molecules in the atmosphere, and shorter wavelengths of light (like blue) are scattered more than longer ones.
This scattering, called Rayleigh scattering, causes the sky to look blue during the day.The sky appears blue because scattered sunlight interacts with molecules in the atmosphere, scattering shorter wavelengths of light (blue) more efficiently than longer wavelengths.
This scattering, known as Rayleigh scattering, is why the sky appears blue to observers on Earth.The sky appears blue because sunlight is scattered by molecules in the Earth's atmosphere, and shorter wavelengths of light (like blue) are scattered more than longer wavelengths.
This scattering, called Rayleigh scattering, is why the sky appears blue during the day.TinyLlama 1.1B Chat: all 3 outputs
The sky is blue because it reflects the sun's rays, which are responsible for its color. The blue hue is the result of the scattering of light by the atmosphere, which consists of gases such as oxygen, nitrogen, and argon, among others. The scattering of light is a process that occurs at different wavelengths, depending on the composition of the gas. This interaction between the sun's rays and the atmosphere results in the formation of a spectrum that is unique to the sky.The sky is blue because of the combination of various colors and wavelengths that are emitted by the Earth's atmosphere. The colors of the sky are determined by the composition and thickness of the atmosphere, which in turn reflects and absorbs different frequencies of light. Blue is the color that results from the highest concentration of wavelengths in the visible range, and as such, it is the most common color seen from Earth. The combination of these colors creates a beautiful and mesmerizing visual effect that is unique to the sky.The sky is blue because the blue color is formed from the chemical compound known as anthocyanin. Anthocyanins are a group of pigments that occur naturally in plant cells and contribute to the vibrant color of fruits, vegetables, and flowers. Anthocyanins are also found in blue fruits like blueberries, blackberries, and raspberries, which are known for their unique flavor and medicinal properties. The blue color of the sky is due to the scattering of light by these anthocyanins, creating a stunning visual effect.
In addition to anthocyanins, other pigments found in plants, such as carotenoids and phycotoxins, may contribute to the blue color of the sky. However, the amount of blue pigments present in the sky is much higher due to the large concentration of anthocyanins.Related
Markdown version for agents: /tests/writing-prompt-w05.md