LIA Crossword

4. The variable measured in an experiment.
5. The hard outer shell of the earth including the crust and uppermost mantle.
6. Atoms of the same element with different numbers of neutrons.
7. A gap in the rock record.
11. Type of plate boundary where earthquakes are mainly found.
12. Harmful contaminants released into the environment by human activity.
14. The preserved remains or evidence of an organism.
15. States that in undisturbed rock layers, the bottom layer is the oldest.
18. Doing an experiment multiple times.
19. Rock made of sediment which has been pressed together and cemented.
20. ______ age dating compares the age of a sample to the age of a different sample.

1. Copying an experiment to see if you get the same results.
2. Type of plate boundary where mountains form.
3. Removing large areas of trees, causing loss of habitat and increased erosion.
6. Rock formed by the cooling and crystallization of lava or magma.
8. Rock formed by extreme heat and pressure deep underground.
9. The variable changed in an experiment.
10. The time it takes for half of an isotope sample to decay.
13. ______ age dating finds the numerical age of a sample.
16. The movement of rock in the mantle driven by heat.
17. Type of plate boundary where new ocean basins form.