Light rays travel in straight lines but they bend when they pass from one material into another such as air into glass. A magnifying glass bends lots of rays so that they all come to one point called the focus.
Atom bombs release lots of energy when billions of atoms are split by neutrons. Hydrogen bombs release energy when hydrogen atoms are smashed together by high temperatures.
Although the feather and the hammer have different masses, they both accelerate at the same rate due to the gravity of the moon. There is no atmosphere on the moon so the friction force due to atmospheric drag is zero.
Water has 2 Hydrogen and 1 Oxygen atoms making up each molecule. If the Hydrogen atoms are replaced by heavier Hydrogen (deuterium) atoms, then each water molecule is slightly heavier. Hence the term heavy water which can be used in the Nuclear industry.
The leaves of plants absorb most colours of light to make their food by photosynthesis. Leaves reflect the colour green so we see leaves as green.
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