The Process of Scientific Investigation：練習問題

In the past, many people believed that diseases were caused by "bad air". After the discovery of bacteria through microscopes, this knowledge changed. What does this tell us about scientific knowledge?

In a fair test, a student is investigating how the mass of a toy car affects the distance it travels. The student keeps the ramp height and the surface of the floor the same. Why is it important to keep these factors unchanged?

A student wants to test if the color of a container affects how quickly the water inside it cools down. She has a black container and a white container. Which of the following setups describes a fair test?

A student needs to measure exactly \(50\text{ ml}\) of water for an experiment. Which instrument is most suitable for this task?

Scientific investigations help us understand the natural world, but they have limitations. Which of the following questions cannot be solved by science alone?

If two scientists perform the same experiment but get different results, what should they do next to ensure their findings are reliable?

After observing a natural phenomenon and forming a hypothesis, a student needs to continue the investigation. What are the next two logical steps they should take in the process of scientific investigation to test their idea?

Throughout history, scientific understanding has often changed (for example, from believing the Earth was the center of the universe to knowing the Sun is). What does this tell us about the nature of scientific knowledge, and why is this important?

A student is investigating how the number of paper layers affects the weight a paper bridge can hold before collapsing.

(a) What is the independent variable (the factor being changed) in this investigation? (1 point)

(b) Suggest one factor that must be kept the same (controlled variable) to make this a fair test. (1 point)

(c) Why should the student perform the test more than once for each number of layers instead of just once? (1 point)

A student wants to find out if water evaporates faster when it is placed in a wide bowl compared to a tall, narrow glass.

(a) Identify the independent variable and the dependent variable for this experiment. (2 points)

(b) To ensure the test is fair, explain why both containers must be placed in the same location in the room. (1 point)

(c) Scientists once believed that water only turned into a gas when it reached its boiling point. Explain how systematic evidence from an experiment like this helps scientists update or change scientific knowledge. (1 point)