Expedition 2: How Do Scientists Know What to Test?

Catching up, looking ahead, and more scientific practices

In last weeks’s video, Kit described the process of asking questions and gathering and evaluating information to try to answer the question: When and how did the warrah make it to the Falkland Islands?

In this week’s video, Kit will be:

• developing and using models,
• constructing explanations and theories, and
• starting to plan an investigation.

Like we have mentioned before, these are all practices of scientists and engineers. You might notice that some of these practices will show up more than once and rarely by themselves. This is because the practices are so connected to one another that it is difficult to imagine using only one without one or more others at the same time.

For example, if you saw a puddle of water in the middle of the floor (hopefully before you stepped in it), you would immediately start thinking about how it got there, coming up with possible explanations, planning some ways of testing those ideas, and more! It’s just what we do! It’s what makes us all scientists!

Like us, Kit is doing what scientists do by using many of these practices to answer questions about the warrah.

Questions, models, and possible explanations

Kit is asking two questions:

• When did the warrah arrive in the Falkland Islands?  and 
• How did the warrah get to the Falkland Islands? 

In order to reach answers to these questions, Kit will need to develop some possible models or simulations that will try to explain why the warrah was the only land mammal on the island when European explorers arrived in 1690. Models help us imagine and represent things that we haven’t actually seen. Even though we didn’t see the warrah swim from Argentina to the islands, we can think about what it would have been like for a fox to try and swim 300 miles to the island. Models help us make predictions in the form of “if…then…therefore.” Kit can then test these predictions to get closer to identifying a most likely explanation. The results of the tests will hopefully help Kit decide which explanation the results fit best, or if a different explanation needs to be explored.

In order to find out when the warrah reached the island, Kit needs to know as much about the warrah’s history as possible. From written records and other sources, she was able to find out that the warrah existed when European explorers reached the islands in 1690. She will also need to find out how long the warrah was on the islands before Europeans got there. This answer to this question may help explain how it got there.

Kit describes some possible models for the warrah reaching the island, which were also suggested by you in the latest twitter chat!

The warrah might have:

• walked across land bridge or ice bridge;
• swum;
• been brought by humans.

Developing a hypothesis, and gathering data

Using these models, kit can gather more information to help decide if some of these explanations are more likely than others. Kit will develop a hypothesis or prediction that can be tested by using evidence from prior knowledge and other sources of information to identify the most likely explanation.

Even though we have developed a theory, our work is not done! By identifying her questions and most likely explanations, or hypotheses, Kit can now decide what data she will need to help her make progress towards an answer to her questions. Once she knows what data she will need, she can plan her steps to collecting those data and how she will use them to help her answer her questions. Kit is currently in the Falklands gathering data to use as evidence for either supporting the hypothesis, or indicating that a different explanation is more likely.

Explanations lead to more questions

Another question that Kit will be trying to answer is whether or not there were any humans on the islands before the Europeans got there. If she can find evidence of earlier human activity, that might further suggest that the warrah was brought by early humans. What are some things that might indicate humans living on the islands before Europeans?

Thanks to technology, we are able to see where Kit’s team has been conducting their research and have had her answer the fantastic questions that you have asked! In Kit’s amazing video updates we have been able to observe some of the work she is doing including collecting sediment cores, which you will be hearing more about soon!

Tune in next week to learn more about planning Kit’s investigation and how she will use the data that she gathers to help her tell the story of the warrah.

What do you think?

Here are some questions to discuss with your class, or to investigate on your own!

• Why is background research so important to developing a hypothesis?
• If you were the first person in the Falkland Islands what sorts of things would you need to survive? Keeping survival in mind, what parts of the islands would be best for settling?
• Why are the answers to these questions important to consider for Kit’s research?
• Can you think of another time when you needed more information before trying to answer a question of your own?

Have more questions?