nature of science

1

100

What is the main purpose of a scientific experiment?

• To prove an opinion is correct

• To test what happens when something is changed

• To guess the answer

• To ask people what they think

To test what happens when something is changed

200

Which investigation is an experiment?

• Watching birds at a park

• Asking students about their favorite food

• Changing the amount of water given to plants and measuring their growth

• Reading a book about animals

Changing the amount of water given to plants and measuring their growth  

300

21. A student wants to determine whether the temperature of water affects how quickly sugar dissolves. She uses 100 mL of water in three cups. One cup is cold, one is room temperature, and one is hot. She adds the same amount of sugar to each cup. What is the independent variable?

• The amount of sugar

• The amount of water

• The temperature of the water

• The time it takes the sugar to dissolve

• The temperature of the water

400

 A scientist hypothesizes that plants grow taller when exposed to more sunlight. After conducting the experiment, the plants receiving more sunlight are actually shorter. What should the scientist conclude?

1. The data should be changed to match the hypothesis.
2. The hypothesis was supported completely.
3. The results did not support the hypothesis.

• The results did not support the hypothesis.

500

 A student claims, “My experiment proves that all plants grow best under blue light because my four plants grew taller under blue light.” What is the biggest problem with this conclusion?

1. Plants cannot grow under blue light.
2. The evidence from four plants may not be enough to make a claim about all plants.
3. Blue light cannot be tested scientifically.
4. The student should not have measured plant growth.

• The evidence from four plants may not be enough to make a claim about all plants.

2

100

Which of the following is an example of an observation?

• The flower is the prettiest in the garden.

• The flower must be healthy.

• The flower has five red petals.

• I think the flower likes sunshine.

• The flower has five red petals.

200

What is the purpose of a control group?

• To provide something to compare the experimental results with

• To make the experiment more exciting

• To receive every treatment

• To guess the results

To provide something to compare the experimental results with

300

In the experiment above, why should the student use the same amount of sugar in each cup?

• So the sugar will taste the same
• So the temperature is the only factor being changed
• So the experiment will take less time
• So the sugar will dissolve at the same speed

• So the temperature is the only factor being changed

400

Which statement best explains the difference between an observation and an inference?

1. An observation is based on evidence directly noticed, while an inference is an explanation based on that evidence.
2. An observation is always correct, while an inference is always incorrect.
3. An observation is a guess, while an inference is a measurement.
4. Observations can only be made during experiments.

An observation is based on evidence directly noticed, while an inference is an explanation based on that evidence

500

Which conclusion is most appropriate after an experiment shows that Brand A paper towels absorb more water than Brands B and C?

1. Brand A is the best paper towel for every purpose.
2. Brand A absorbed more water than Brands B and C under the conditions tested.
3. Brand A will always absorb more water than every paper towel ever made.
4. Brand A is the most popular paper towel.

• Brand A absorbed more water than Brands B and C under the conditions tested.

3

100

In an experiment, what is a variable?

• Something that can change

• The final answer

• A scientist's opinion

• A type of observation only

• Something that can change

200

Which statement is testable?

• Chocolate ice cream is the best flavor.

• Plants grow faster when given more hours of light.

• Rain is beautiful.

• Summer is the best season.

Plants grow faster when given more hours of light.

300

Two students conduct the same experiment, but they get different results. What is the best scientific response?

1. One student should change their data.
2. They should compare their procedures and repeat the investigation.
3. They should decide that both experiments are wrong.
4. They should choose whichever result they like better.

• They should compare their procedures and repeat the investigation.

• 
  

400

A student sees that a plant's leaves are drooping and says, “The plant needs water.” What is the student's statement?

A verified measurement

An observation

An inference

A controlled variable

An inference

500

A scientist discovers that a new observation does not fit an existing scientific explanation. What should the scientist do?

1. Ignore the observation.
2. Change the evidence.
3. Investigate the new evidence and consider whether the explanation needs to be revised.
4. Stop doing science.

• Investigate the new evidence and consider whether the explanation needs to be revised.

4

100

• Jamal wants to find out whether the amount of sunlight affects plant growth. What is the variable he changes?
• The type of plant
• The amount of sunlight
• The height of the plant at the end
• The ruler used to measure the plant

• The amount of sunlight

200

Why do scientists often perform multiple trials?

• To make the experiment last longer

• To make their results more reliable

• To change the question

• To avoid recording data

To make their results more reliable

300

 A scientist observes that a certain type of bird eats more seeds in the morning than in the afternoon. Which question would be the most testable based on this observation?

1. Why are birds interesting?
2. Are morning birds happier than afternoon birds?
3. Does the time of day affect how much seed the birds eat?
4. Is eating seeds the best thing for birds?

• Does the time of day affect how much seed the birds eat?

400

A scientist wants to determine whether a new fertilizer increases plant growth. Which setup would provide the strongest comparison?

1. Give fertilizer to one plant and nothing to another plant.
2. Give fertilizer to both plants but use different amounts of water.
3. Give fertilizer to one group of similar plants and no fertilizer to another similar group, while keeping other conditions the same.
4. Give different fertilizers to every plant.

• Give fertilizer to one group of similar plants and no fertilizer to another similar group, while keeping other conditions the same.

500

 Which situation best demonstrates why scientific investigations do not always follow a strict sequence of steps?

1. A scientist asks a new question after making an unexpected observation and conducts another investigation.
2. A scientist refuses to collect data.
3. A scientist guesses an answer and never tests it.
4. A scientist chooses not to use evidence.

• A scientist asks a new question after making an unexpected observation and conducts another investigation.

5

100

Why is it important to keep most conditions the same during an experiment?

• To make the experiment harder

• To make sure the changed variable is responsible for the results

• To use more materials

• To finish the experiment faster

• To make sure the changed variable is responsible for the results

200

Which of these is a personal opinion?

• The thermometer reads 25°C.

• The rock weighs 10 grams.

• Dogs are the best pets.

• The plant grew 3 centimeters.

Dogs are the best pets.

300

A student tests three brands of paper towels to determine which absorbs the most water. He uses a different amount of water for each brand. Why could this make his results unreliable?

1. Paper towels should never be compared.
2. The amount of water is another variable that could affect the results.
3. The student tested too many brands.
4. Absorption cannot be measured scientifically.

• The amount of water is another variable that could affect the results.

400

A scientist performs an experiment three times and gets similar results each time. What does this most strongly suggest?

1. The results are more reliable.
2. The hypothesis must be true in every situation.
3. The experiment no longer needs to be explained.
4. The scientist does not need to collect more evidence.

• The results are more reliable.

500

A researcher is studying whether exercise affects heart rate. Which measurement would be the dependent variable?

1. The amount of exercise
2. The type of exercise equipment
3. The person's heart rate
4. The number of researchers

• The person's heart rate