Across
- 3. produce and discharge (something, especially gas or radiation).
- 5. a continuous area or expanse which is free, available, or unoccupied.
- 9. the external form or appearance characteristic of someone or something; the outline of an area or figure.
- 11. able to be seen.
- 12. a straight line from the center to the circumference of a circle or sphere.
- 16. the curved path of a celestial object or spacecraft around a star, planet, or moon, especially a periodic elliptical revolution.
- 17. the strength and vitality required for sustained physical or mental activity.
- 18. an amount of space between two things or people.
- 19. a stable subatomic particle occurring in all atomic nuclei, with a positive electric charge equal in magnitude to that of an electron, but of opposite sign.
- 21. the amount of space that a substance or object occupies, or that is enclosed within a container, especially when great.
- 23. a subatomic particle of about the same mass as a proton but without an electric charge, present in all atomic nuclei except those of ordinary hydrogen.
- 24. (of an object or structure) not likely to give way or overturn; firmly fixed.
Down
- 1. represent (something) in graphic form.
- 2. a coherent, typically large body of matter with no definite shape.
- 3. of, worked by, charged with, or producing electricity.
- 4. an explosive warhead carried by a missile.
- 6. of very great extent or quantity; immense.
- 7. prone to change, fail, or give way; not stable.
- 8. a part or aspect of something abstract, especially one that is essential or characteristic.
- 10. the space (usually measured in degrees) between two intersecting lines or surfaces at or close to the point where they meet.
- 13. break or cause to break forcibly into parts, especially into halves or along the grain.
- 14. atoms as a source of nuclear energy.
- 15. a colorless, odorless, highly flammable gas, the chemical element of atomic number 1.
- 20. a minute portion of matter.
- 22. relating to the nucleus of an atom.