Howardites

A printable worksheet for the lesson Half-life and dating meteorites (GCSE). It prints on A4 without the website around it. The answers are on a separate sheet for the teacher.

Answer sheet for teachersBack to the lessonAll worksheets

GCSE · Ages 14 to 16 (Years 10 and 11)Howardites worksheet

Half-life and dating meteorites

Name:Class:Date:

Key words

Isotope
One of two or more forms of the same chemical element whose atoms have different numbers of neutrons, and so different masses.
Meteorite
A meteorite is a piece of space rock that has survived its fall through the air and landed on Earth.
Half-life
The time it takes for half of the atoms of a radioactive isotope in a sample to decay.
Mineral
A mineral is a natural solid with a fixed chemical recipe and an orderly inner arrangement of atoms.
Sulfide
A sulfide is a mineral made of a metal combined with sulfur, such as troilite in meteorites.
Chondrite
A chondrite is a stony meteorite full of tiny round grains called chondrules, and almost unchanged since the Solar System formed.

Choose the right answer

Circle the letter of the right answer.

  1. Why does dating the oldest meteorite grains tell us the age of the Solar System?
    • AThey formed inside the Sun before fusion began
    • BThey arrived on Earth 4.6 billion years ago
    • CThey were the first solids around the young Sun
    • DThey formed when Earth's crust was recycled
  2. Carbon-14 has a half-life of about 5,730 years. What fraction is left after 17,190 years?
    • A1/16
    • B1/6
    • C1/8
    • D1/3
  3. When an unstable nucleus decays, what does it change into?
    • AA compound of the same element
    • BA heavier isotope of the same element
    • CAn ion of the same element
    • DA different element
  4. A mineral holds 1/16 of its original parent isotope. The half-life is 1 billion years. How old is the mineral?
    • A16 billion years
    • B4 billion years
    • C8 billion years
    • D2 billion years
  5. A sample's activity is 800 counts per minute and its half-life is 2 days. What is its activity after 6 days?
    • A200 counts per minute
    • B400 counts per minute
    • C267 counts per minute
    • D100 counts per minute

True or false?

Is the answer given right? Tick True or False.

  1. Which statement about the decay of a single unstable nucleus is true?

    Answer given: It decays only when heated TrueFalse

  2. When does a mineral's radioactive clock start?

    Answer given: When the mineral crystallises TrueFalse

Write your answer

Answer in a word or a short sentence.

  1. Why is uranium-238 a poor clock for something only a few hundred years old?
  2. Which graph shape shows the number of radioactive nuclei left as time passes?
  3. What did Clair Patterson use in 1956 to find the age of Earth and the meteorites?

Task

Model decay with 100 coins or dice. Shake them all, remove those showing heads (or a six), count what is left and repeat for ten throws. Plot the number remaining against throw number and read off the 'half-life' from your graph. Why do the class's combined results give a smoother curve than one person's?

Howardites · free to copy for use in your classroom · answers are on the separate teacher's answer sheet