ARAL SCIENCE

12345678910111213141516171819202122232425
Across
  1. 4. – A molecule made of three oxygen atoms that forms a protective layer in the stratosphere, shielding us from harmful UV rays.
  2. 7. – A measure of how much mass is contained in a given volume; it explains why a massive steel cruise ship can float while a tiny pebble sinks.
  3. 9. – The invisible force that keeps our feet on the ground and caused an apple to allegedly spark Isaac Newton's greatest theory.
  4. 10. – The fourth state of matter, consisting of superheated gas with an electrical charge; it makes up lightning, neon signs, and 99.9% of the visible universe.
  5. 14. – Known as the powerhouse of the cell, this organelle has its own DNA and is believed to have once been an independent bacterium.
  6. 15. – The substance in a solution that does the dissolving; water is famously known as the "universal" one because it dissolves more substances than any other liquid.
  7. 17. – A substance with a pH less than 7 that tastes sour and can donate a hydrogen ion; your stomach contains a strong one to help break down food.
  8. 18. – The speed of an object in a specific direction, distinguishing it from simple speed in physics calculations.
  9. 19. – This subatomic particle carries a negative charge and zips around the nucleus so fast that it exists in a "cloud."
  10. 21. – The second lightest element in the universe, it is so light that Earth's gravity can't hold onto it, causing it to escape into space if released.
  11. 22. – An object's resistance to any change in its state of motion, famously described in Newton's First Law.
  12. 23. – A biological catalyst, usually a protein, that speeds up chemical reactions in the body without being consumed in the process.
  13. 25. – The phase change from liquid to gas that doubles as nature's cooling mechanism, which is why humans sweat.
Down
  1. 1. – The variety of life in the world or in a particular habitat, which acts as a safety net keeping entire ecosystems resilient.
  2. 2. – The process plants use to convert sunlight into energy; it is also the primary source of the oxygen we breathe.
  3. 3. – A high-temperature exothermic chemical reaction between a fuel and an oxidant, more commonly known as burning.
  4. 5. – The type of rock formed when existing rocks are changed by intense heat and pressure deep underground, like limestone turning into marble.
  5. 6. – A change that occurs in our DNA sequence, which can be caused by mistakes during cell division or environmental factors, serving as the raw material for evolution.
  6. 8. – The green pigment in plants that absorbs light energy; it contains a magnesium atom at its core.
  7. 11. – The envelope of gases surrounding the Earth, held in place by gravity, which prevents us from freezing at night and burning up during the day.
  8. 12. – The fundamental structural and functional unit of all living organisms, first discovered under a microscope by Robert Hooke in 1665.
  9. 13. – The double-helix molecule that contains the genetic blueprint for life; if you uncoiled all of it from just one of your cells, it would stretch about two meters long.
  10. 16. – An astronomical event that occurs when one celestial body moves into the shadow of another, temporarily blocking its light.
  11. 20. – The force that resists motion when two surfaces slide against each other, generating heat—which is why rubbing your hands together warms them up.
  12. 24. – Molten rock stored beneath the Earth's crust; once it breaks through the surface during an eruption, its name changes to lava.