Why Fingers Wrinkle in Water
8 min 4 scenes
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Science & Nature
Physics, chemistry, biology, Earth science, space, and the environment.
冰浮在水上的秘密
理解密度和分子结构如何决定物质的浮沉。
14 min 7 scenes
冰浮在水上的秘密
理解水结冰时体积膨胀、密度减小的分子机制
14 min 7 scenes
Which ideas help explain why a glacier shapes a landscape?
8 min 4 scenes
Magnetic Attraction: The Atomic Secret
You will understand how unpaired electrons and magnetic domains explain why iron sticks and copper does not.
16 min 8 scenes
Magnetic Attraction: The Atomic Secret
Magnets attract ferromagnetic materials like iron because their atoms have unpaired electrons that can align their magnetic fields.
8 min 4 scenes
Why Magnets Attract Some Materials
8 min 4 scenes
Why Magnets Attract Some Materials
You will be able to explain that ferromagnetic materials have magnetic domains that align with an external field, while other materials lack this ability.
14 min 7 scenes
太阳的温度悖论
理解太阳大气温度分布的反直觉特性及其物理机制。
10 min 5 scenes
Vancouver's Climate Secret
Understand how ocean currents and mountain barriers create a mild coastal climate despite high latitude.
10 min 5 scenes
Water's Strange Freeze: Why Ice Floats
Understand the molecular reason for water's density anomaly.
10 min 5 scenes
Why Is the Sky Blue?
You will understand how white sunlight is actually a mixture of colors, how the atmosphere scatters light, and why blue light gets scattered the most.
16 min 8 scenes
候鸟迁徙探秘
学生能够解释候鸟迁徙的三大主因（食物、温度、繁殖）并能用科学原理解释至少两种迁徙导航机制。
24 min 12 scenes
What Makes a Goldendoodle a Goldendoodle
10 min 5 scenes
Goldendoodle Coat Genetics
10 min 5 scenes
月食探秘
学完本课后，你将能用自己的话解释月食的形成原因，区分月食类型，并准确预测月食发生的条件。
20 min 10 scenes
Why Shadows Change Size
By the end of this course, learners can explain why shadow length changes with the Sun's position and predict how a shadow will change based on the angle of the light source.
22 min 11 scenes
Why Shadows Change Size
Learners can explain that a shadow's size changes because of the angle between the light source and the object, and the distance from the light source, using the model of straight-line light rays.
22 min 11 scenes
The Shadow Geometry
Learners will be able to explain how light source angle and object positioning dictate shadow length and shape.
18 min 9 scenes
How a Vacuum Cleaner Lifts Dust
Learners can explain, in their own words, how differences in air pressure created by a moving airstream move dust into a vacuum cleaner, and can identify what would make a vacuum stop working.
22 min 11 scenes
Why Paper Curls When Wet
Learners can explain, with evidence, why wet paper curls by connecting fiber swelling, uneven expansion across the sheet, and the role of drying — and can predict how changing the wet region will change the curl.
24 min 12 scenes
Why Balloons Shrink in the Freezer
Learners can explain, using particle motion and the relationship between temperature, pressure, and volume, why a sealed balloon shrinks in the cold and expands again when warmed, and they can apply that model to predict the behavior of gases in other everyday situations.
24 min 12 scenes
Why Does Dew Form Overnight?
Learners can explain, with evidence, why dew forms on clear, still nights — distinguishing observed cooling, invisible water vapor, and condensation at the dew point — and can revise the common belief that dew falls from the sky.
24 min 12 scenes
Why Does a Metal Pan Handle Get Hot?
Learners can explain how heat travels through solid metal by particle collisions, identify common conductors and insulators, and apply that knowledge to predict whether an object will feel hot or stay cool.
24 min 12 scenes