Mars

Mars

Pencil and paperOnline interactive
Overview
Using this Resource
Connecting to the Curriculum
Marking Student Responses
Working with Students
Further Resources
This task is about how knowledge can change over time.
 
Mars-NASA.jpg
Image source: NASA
When early astronomers started looking at Mars using their primitive telescopes they could see that the planet had areas of dark colour that seemed to change size as time passed. It was thought these dark areas were plants that grew in the warmer times of the year and then died off in the winter, much like on Earth. They could also see dark lines on the surface. Some people thought these dark lines were canals and thought this proved that there must be some form of intelligent life on Mars to have made them. Most scientists no longer believe this.

Question 2Change answer

a)  Name three things that scientists believe about Mars now.
1.
2.
3.

Question 2Change answer

b) Explain how scientists have gathered information that led them to change their beliefs.

Question 2Change answer

c)  Explain why the early astronomers thought the way they did.
Task administration: 

This task can be completed with pencil and paper or online.

Two websites that support finding information for this resource are:

School Journal Part 2, Number 1, 2000 contains an article, Return Ticket, Please by David Hill. This article could provide information required for the completion of this assessment task if access to the internet is unavailable.

This assessment resource could be used as a:

  • diagnostic assessment to uncover students’ current ideas; or
  • formative assessment where students research to find the information they need about Mars to answer the question; or
  • summative assessment following work about Mars, in which case students could be expected to use their knowledge to explain what is currently believed about the environment on Mars.
Level:
3
Curriculum info: 
Science, Understanding about science, Planet Earth
Keywords: 
astronomical systems, space exploration, Mars
Description of task: 
Task: Students use recent information obtained from space exploration to show how and why beliefs have changed over time. Assessment focus: interpreting information about the provisional nature of science.
Science capabilities: 
Gather and interpret data, Use evidence
Answers/responses: 
 
a) Any 3 of:

  • Very cold and windy
  • Dust storms
  • Large mountains, canyons and craters
  • Appears to lack active plate tectonics/ no evidence of current volcanic activity
  • Erosion
  • No water currently but some sort of fluid present in the past
  • Frozen water and solid carbon dioxide present
  • Thin atmosphere with very little oxygen
  • Seasonal changes
  • No evidence of life (although this is still controversial)
  • Large, but not global, weak magnetic fields exist.
b) An explanation involving any 1 of:

  • Advances in space exploration have allowed for craft to orbit and land on Mars.
  • The existence now of the Hubble Space telescope/ more powerful telescopes has enabled photos to be taken and various measurements carried out.
c) Student's answer recognises that the technology had not been invented.
Trialled in two Level 3 classrooms.
Diagnostic and formative information: 

This resource highlights how advances in technology have allowed scientists to modify their ideas about Mars. Use the resource to check that students do realise that science knowledge changes over time. This is an important Nature of Science idea. Science knowledge relies on evidence from observation and experiments. Science ideas sometimes need to be revised as new evidence becomes available. In the trials many students did not appear to have a clear understanding of either how or why science knowledge has changed.

Next steps
The website Science IS includes a similar activity at L5-6. Science IS also has an activity at Level 3-4 that focuses on the moon and reinforces the idea that new technologies can provide evidence for or disprove current science knowledge.

A possible next step could be to explore how other scientific ideas have changed over time. For example once people believed the Earth to be the centre of the universe and that the world was flat. Our knowledge of dinosaurs and other extinct animals changes as new discoveries are made and sometimes animals that were thought to be extinct are "rediscovered" (for example the takahe). Recently there has been discussion as to whether or not Pluto should be classified as a planet.

As students research how various science ideas have changed, ask questions that encourage the students to think about why these changes happened.

  • What new evidence became available? (For example; were fossils found in new places?)
  • Did the development of new technologies allow things to be seen or measured that were not possible before? (For example; increasingly powerful telescopes.)
  • Did the scientists think in different ways or ask new questions? (For example; Copernicus in the 16th Century began to think differently about the universe. He challenged the accepted belief at that time that the Earth was the centre of the universe. It wasn’t till much later, though, when Galileo was able to use a simple telescope to gather data that these ideas became widely accepted.)

Ministry of Education (2006). Connected 2, Wellington: Learning Media. This edition of the Connected series has an article about how ideas about light have changed over time.
The following website provides information about how some science ideas have changed.
http://www.pbs.org/wgbh/aso/