Howardites

A printable worksheet for the lesson Carbonaceous chondrites (Start here: Enthusiast). It prints on A4 without the website around it. The answers are on a separate sheet for the teacher.

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Start here: Enthusiast · Teens and adultsHowardites worksheet

Carbonaceous chondrites

Name:Class:Date:

Key words

Chondrite
A chondrite is a stony meteorite full of tiny round grains called chondrules, and almost unchanged since the Solar System formed.
Organic matter
Organic matter in meteorites is carbon-based chemistry, made without life, that ranges from simple molecules to large, tar-like solids.
Isotope
One of two or more forms of the same chemical element whose atoms have different numbers of neutrons, and so different masses.
Chondrule
A chondrule is a tiny round grain, often smaller than a grain of rice, that formed as a melted droplet in space before the planets existed.
Amino acids
Amino acids are small carbon-based molecules, the building blocks of proteins, and some meteorites contain ones made without life.
Ryugu
A dark, carbon-rich near-Earth asteroid shaped like a spinning top, sampled by Japan's Hayabusa2 mission.

Choose the right answer

Circle the letter of the right answer.

  1. Does the organic matter in carbonaceous chondrites show that life existed on asteroids?
    • ANo, it shows complex chemistry happened naturally
    • BYes, the sugars must have come from living cells
    • CYes, the amino acids prove life once existed
    • DNo, because all of it is contamination from Earth
  2. A slice shows large chondrules and big, pale CAIs. Which group fits best?
    • ACK
    • BCV
    • CCI
    • DCO
  3. Where and when did the Murchison meteorite fall?
    • ATanzania, in 1969
    • BAustralia, in 1969
    • CCanada, in 2000
    • DFrance, in 1864
  4. How soon can sulphate crystals begin to grow on the surface of a fresh CI or CM chondrite?
    • AWithin weeks or months
    • BOnly once it has been cut open
    • COnly after thousands of years
    • DOnly after several centuries
  5. Roughly what share of observed falls are carbonaceous chondrites?
    • AAbout 4 per cent
    • BUnder 0.1 per cent
    • CAbout 80 per cent
    • DAbout 40 per cent

True or false?

Is the answer given right? Tick True or False.

  1. A fresh CM stone has just landed on a lawn. Which first step best protects it?

    Answer given: Lift it with clean foil and seal it away dry TrueFalse

  2. Which everyday things are a particular risk to the organic compounds in a fresh fall?

    Answer given: Fingerprints, plastics and dust TrueFalse

Write your answer

Answer in a word or a short sentence.

  1. Why were Murchison's amino acids judged to come from space rather than contamination?
  2. Putting the parts together, what does the label CM2 describe?
  3. In what form is much of the carbon in carbon-rich carbonaceous chondrites?

Task

Make a small chart of the carbonaceous chondrite groups with their letters, type meteorites and one key feature each. Use it to decode labels like CM2, CV3 and CI1.

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