Scientific Explanations
Scientists use these to explain observations of the natural world.
Scientific explanations
This usually comes first when scientists investigate something: they identify what they want to find out.
Questioning or observing
This is information collected during an investigation that can be used to support or contradict an explanation.
Evidence
A scientist writes a detailed research paper for other scientists but creates a picture-based explanation for young children. Why are the two explanations different?
Pictures will be more engaging for young children, they will understand more.
Scientific explanations can be changed or refined when scientists collect this.
New evidence
This is an explanation proposed before an investigation that can be tested using evidence.
Hypothesis
A student researches how sunlight affects plants and then predicts that plants receiving more sunlight will grow taller. What is this prediction called?
Hypothesis
One study contradicts the results of eleven previous studies. Scientists should do what with the new results?
Repeat the experiment - one contradicting study does not change an accepted scientific explanation
This display of data shows the information using a grid system and a line to show change.
A (line) graph.
Pluto was once commonly taught as the ninth planet but was later classified as a dwarf planet. What does this demonstrate about scientific knowledge?
Scientific explanations can be changed when there is new evidence.
A scientific explanation needs to have this quality: there must be some possible observation or experiment that could show it is wrong.
Falsifiable
A student tests whether fertilizer affects plant growth. She changes the amount of fertilizer but keeps the type of plant, amount of water, soil, and sunlight the same. What are the conditions she keeps the same called?
Controlled variables
A student investigates whether wing length affects the distance a paper airplane travels. She changes the wing length and measures the distance travelled. What is the dependent variable?
Flight distance
Beth and Sam are having an argument about whether the food additive aspartame is safe for humans or not.
Beth believes it is unsafe because she watched multiple videos on TikTok of a food scientist warning about the dangers of aspartame.
Sam believes that aspartame is safe because he read over seven scientific studies in scientific journals proving it is safe in humans in low doses.
Who is correct?
Sam is correct as TikTok is not a reliable source of information.
For many years, some people believed the Sun moved around Earth because it appeared to travel across the sky. What later explanation better accounts for the daily movement of the Sun across the sky?
Earth rotates on its axis.
A student sees water droplets forming on the outside of a cold glass. Explain the scientific explanation that best accounts for where the water came from.
The water vapour in the air condensed onto the cold surface
Put these steps in the most logical order:
- Make a conclusion
- Ask a question
- Conduct an investigation
- Research the topic
- Form a hypothesis
Question → research → hypothesis → investigation → conclusion
A student is completing an experiment to test whether sunlight affects plant growth. They use two plants and grow them in different places, one in a sunny window and one in a dark closet. Every day, the student measures the height of each plant.
List at least four variables that would need to be controlled to ensure the experiment is valid.
Possible answers not limited to:
- Type of plant used
- Type of soil used
- Amount of water given to each plant
- Amount of fertilizer given to each plant
First Nations, Métis, and Inuit Peoples may communicate explanations of natural phenomena through written texts, traditional knowledge, visual forms, verbal presentations and these.
Stories or legends
Generations of people used to think that you had to appease a higher power in order for it to rain at a specific location. What is the modern scientific explanation for why different locations receive different amounts of rainfall?
Global wind patterns, the shape of the Earth, ocean temperatures and different air temperatures all change how likely an area is to receive rain.
A student says, “The puddle disappeared because the water was eaten by invisible creatures.” What important feature would this explanation need before scientists could properly investigate it?
Falsification
A student wants to know whether water temperature affects how quickly a tablet dissolves. She changes the temperature, but also changes the amount of water and number of tablets each time. Why is this a poor experiment?
Because she changed multiple variables, so she cannot determine which variable caused the result.
A student drops a ball three times from the same height and gets bounce heights of 49 cm, 51 cm, and 50 cm. Why are repeated trials useful?
They help increase the accuracy of the investigation.
A scientist has discovered evidence explaining why a local pond freezes during winter, proving hundreds of older studies that concluded the same thing.
She wants to communicate the explanation to three different audiences: other scientists, grade 6 students, and a group of preschoolers.
How would you communicate this evidence to each of those three audiences?
Other scientists: article in a scientific journal
Grade 6 students: explanation in a textbook, labeled diagrams
Preschoolers: a picture book or song
In ye olden days, the sky was very mystical and some groups of people believed that the sky was controlled by a god. What is the modern scientific explanations for why the sky is blue?
The particles in the atmosphere scatter blue light waves more than the other colours