Science t3 old

Question 1

define absolute dating

Question 2

define relative dating

Answer 2

Relative dating is a method used to determine the age of fossils or rocks by comparing them to other layers or objects

Question 3

why are some isotopes are unstable

Answer 3

Some isotopes are unstable because their atomic nuclei have an imbalance between protons and neutrons. When this balance is off, the forces holding the nucleus together become weak, causing the isotope to become radioactive. Unstable isotopes will try to reach a more stable form by releasing energy in the form of radiation, a process called radioactive decay.

Question 4

define half-life

Answer 4

the time that it takes for an isoptope to be halfed say if an isoptioope has a haldfd-life of 5 years after 5 years haqfl; of the ispotope willr emanion after ten half of that and so on

Question 5

define carbon dating

Answer 5

Carbon dating, also known as radiocarbon dating, is a scientific method used to determine the age of an object containing organic material

Question 6

explain how carbon dating works

Answer 6

Absorption of Carbon-14: While alive, organisms absorb carbon-14 from the atmosphere through processes like photosynthesis (in plants) or consumption (in animals).

Decay after Death: Once the organism dies, it stops absorbing carbon-14, and the isotope begins to decay at a known rate, called its half-life (about 5,730 years).

Measuring Decay: Scientists measure the amount of carbon-14 left in the sample. The less carbon-14 present, the older the sample.

Age Estimation: By comparing the ratio of carbon-14 to stable carbon isotopes (like carbon-12), scientists can calculate how many years have passed since the organism died, usually up to about 50,000 years ago.

Question 7

define what an isotope is

Answer 7

An isotope is a version of an element that has the same number of protons but a different number of neutrons.

Question 8

define carbon dating

Question 9

explain how stratigraphy can be used to date fossils.

Question 10

describe the geological timescale

Question 11

explain how fluoride dating can be used to date fossils

Question 12

identify the subatomic parts of an atom and where they are located

Question 13

identify the charges of the different subatomic parts of an atom

Question 14

explain the difference between mass number and atomic number of an atom

Question 15

describe how isotopes release alpha, beta or gamma radiation

Question 16

compare the properties of alpha, beta and gamma radiation

Question 17

alculate the half-life of a sample using data or graphs

Question 18

explain how the half-life of isotopes is used to tell time in radiometric dating

Question 19

describe how the half-life of a radioisotope can be used to ‘tell time’

Question 20

explain how the known half-life of radioisotopes can be used to determine the age of megafauna.

Question 21

state when the megafauna lived and when they went extinct

Question 22

define neutrons

Answer 22

Neutrons are subatomic particles found in the nucleus of an atom. They have no electric charge (neutral) and, along with protons, make up the mass of the atom. Neutrons help hold the nucleus together by balancing the repulsive forces between positively charged protons.