Nature of Science/Cluster 1

Science is open to and must change when new evidence or new scientific interpretations do not support the current theories. Which of the following is/are examples of scientific knowledge changing?

• Christopher Columbus believed the Earth was flat, however we now know the Earth is round.

• Early philosophers believed in a Geocentric model of our Solar System.

• Life was once thought to "spontaneously generate," but we now know that cells come from pre-existing cells.

• The Russians beat us to the Moon.

What are scientific explanations based on?

• Empirical evidence

• Observations

• Logical reasoning

• Predictions

• Models

Ms. Roque noticed that hummingbirds in her yard visited all the flowers, but especially seemed to like the red trumpet-shaped ones. She read that they use the nectar in the flowers for food. She assumed that since the parents were eating nectar, they must feed their babies nectar as well. To her surprise she saw hummingbirds bringing small insects and spiders to feed the young hummingbirds. How does this new evidence affect her original assumption?

• She should be able to stick to her assumption that the babies eat nectar since she thought that first.

• She should believe what she read in the book and disregard what she witnessed.

• She should change her original assumption that they only feed their babies nectar.

• She should ask other people what they think and agree with the majority.

Ms. Roque has been studying bullfrogs from many years. She has noticed that these bullfrogs are now laying eggs 8 days earlier than they did 20 years ago when she first began studying them. The trees around the pond have also grown taller and shade the water more than they did 20 years ago. What would be the best thing for Ms. Roque to do next?

• See if she can determine why they are laying eggs earlier.

• Choose a different species of frog to study for the next 20 years.

• Conclude that the change in tree heights have affected the frogs.

• Assume that the water temperature must have increased so that frogs can lay eggs earlier.

A swim team wants to select one of three fabrics for their new swimsuits. Each fabric is made of a different material. The team does the following experiment: They cut the same size pieces from each fabric and wet each piece with the same amount of water. They hang the pieces in the sunlight and they check every two minutes to see if any of the pieces are dry. What can the team find out about the different fabrics from doing just this experiment?

• If the amount of water affects how long it takes the pieces of fabric to dry.

• If the type of fabric affects how long it takes the pieces of fabric to dry.

• If the amount of water and the amount of light affect how long it takes the pieces of fabric to dry.

• If the type of fabric, the amount of water, and the amount of light affect how long it takes the pieces of fabric to dry.

Scientific knowledge may change as new evidence or information is discovered. Which of the following would NOT be a result of new scientific research and information?

• Binomial nomenclature is assigned to a recently identified plant species.

• An endangered monkey species is put in a reserve for protection from extinction.

• A newly discovered chemical element will be added to the periodic tab le of the elements.

• A nonnative plant species will begin to reproduce rapidly after being introduced into a swamp ecosystem.

Does this image show repetition or replication in science?

• Repetition

• Replication

Does this image show repetition or replication in science?

• Repetition

• Replication

Ms. Roque wanted to see if a new environmentally-friendly pesticide will prevent insect damage to tomato plants. After making a hypothesis, she conducts her experiment. She treats five tomato plants with traditional pesticide and five with the new pesticide. Ms. Roque also leaves five plants untreated as a control. She makes careful notes of how she set up her experiment and then records her data about all of the plants. Why is it important for Ms. Roque to record her procedures and data accurately?

• So that the hypothesis will always be correct.

• So that she can look intelligent when she presents her data at a conference.

• So that society does not waste money buying pesticides that don’t work.

• So that other scientists can replicate the experiment to make sure the results were accurate.

Alex and Jennifer conducted an experiment to test reaction times in grabbing a meter stick after it’s dropped. They each tested 15 friends. Alex dropped the meter stick for his friends and Jennifer dropped the meter stick for her friends while the other one timed the reactions. Jennifer’s friends reacted, on average 0.9 seconds faster than Alex’s friends. Jennifer concluded that her friends were faster. Which of the following should she do next to check her results?

• Try a different reaction time experiment.

• Try the experiment again, this time using a ruler instead of a meter stick.

• Repeat the experiment as it was done the first time but using only Jennifer’s friends.

• Repeat the experiment and have one person drop the meter stick and the other take record the times for all the friends tested.