Nature of Science - Targets 7-8

Nature of Science - Targets 7-8

by KELLY COOTS

Multiple Choice

According to the data table, what was the tallest height of the plant?

• 10 cm

• 24 cm

• 8 mL

• 28 mL

​When the information in the data table is analyzed, there are a couple of points that can be made:

• On days 1 through 3, the amount of water given to the plant was 4 ml.

• On days 4 and 5, the amount of water was doubled to 8 ml.

• On day 4, when the plant was given 8 ml of water, the plant grew 3 cm.

​We might come to the conclusion that doubling the amount of water caused the plant to grow faster, but when we look at days 2 and 3, we see the plant also grew 3 cm. Days 2 and 3 only gave the plant 4 ml of water. The amount of information that we have so far in this investigation is not enough for us to conclude that giving a plant more water will cause it to grow faster.

Multiple Choice

According to the data table, on which day were the plants watered in the afternoon?

• Day 2

• Day 3

• Day 4

• Day 5

Multiple Choice

In order to predict what will happen in the future, you need to have observations and data from investigations in the past. Which of the following would NOT be an example of a prediction about the growth of a plant?

• the plant might die

• the plant might produce seeds

• the plant might produce fruit

• the plants leaves will turn purple

Make predictions. ​

Based on this very short, five‐day investigation of wheatgrass growth, we might begin to make a prediction that more water is a better condition for growing wheatgrass. This answers our investigation question,

Is more water or less water the best condition for growing wheatgrass?​

​We might predict, based on the data we collected, analyzed, and interpreted, that doubling the amount of water a wheatgrass plant will cause it to grow faster. Now we would begin to design a new investigation, based on that prediction. Making predictions is never an “educated guess.” Many times the word hypothesis is defined as “an educated guess.” An educated guess is still just a guess. Based on our observations, we have come to a conclusion that doubling the amount of water will cause a wheatgrass plant to grow faster. We can reword that conclusion to a good scientific prediction:

Multiple Choice

After making our prediction, we may

• start over

• begin to design a new investigation

• analyze the data again

• quit

​If the amount of water a plants receives is doubled, then the plant will grow faster. Notice that this is written as an if...then statement. If this, then that. This is the way a prediction in science is worded. This predication can be tested: an investigation could be designed and carried out to test this prediction. This is a hypothesis: a scientifically testable question, based on evidence and data. No guessing here!

​NEW CONCLUSION

Multiple Choice

Which of the following statements BEST describes making predictions in a scientific investigation?

• an educated guess

• using observations and data from the past to describe what you think might happen in the future

• drawing conclusions about an investigation based on data

• using repeated trials to ensure reliability