The most common misconceptions in science and how to change them

Ask a class “Why does the Moon have phases?” A good part of them will probably answer: “Earth’s shadow falls on the Moon.” It is a reasonable-sounding answer, and often sincerely defended. But it is wrong: in the Moon’s phases, half of the Moon is always lit by the Sun; what changes is how much of that lit side we can see from Earth. Earth’s shadow falls on the Moon only during a lunar eclipse.

Ideas like this are called misconceptions (or prior conceptions). In this post we explain why misconceptions are not random mistakes, six examples that are common in science, and the ways research suggests of changing these ideas.

What is a misconception and why does it last?

Long before they arrive in science class, children and adults build ideas that explain the world: heavy things fall faster, we get warm when we move closer to a fire, plants get their food from the soil. These ideas seem to work because they fit everyday experience. In Making Sense of Secondary Science, Rosalind Driver and colleagues gathered students’ ideas on science topics and reported that the same ideas often appear in similar forms in different students.

Misconceptions last for three reasons:

• Experience supports them. “A sheet of paper falls more slowly than a stone” is a correct observation; what is wrong is the generalisation drawn from it.
• Language reinforces them. Everyday phrases such as “the current got used up” or “the cold came in” call up physically wrong pictures.
• A memorised right answer at the end of a lesson does not erase the old idea. A student gives the “right” answer in the exam but keeps thinking with the old idea in daily life.

A note: education researchers do not agree on one view here. Smith, diSessa and Roschelle (1993) argued that the word “misconception” treats students’ ideas too harshly as “wrong”, and that many of these ideas are made of pieces of intuition that can be useful if used correctly. That is why some researchers prefer “prior conception” or “alternative idea”.

Six common examples

1. “It is hot in summer because we are closer to the Sun”

Earth is closest to the Sun in early January, yet January is winter in the Northern Hemisphere. The cause of the seasons is Earth’s axial tilt: in summer the Sun’s rays hit the surface more directly and the days are longer. See our seasons post and seasons lesson for details. This misconception is so widespread that it also appears among university graduates in Schneps and Sadler’s documentary A Private Universe.

2. “Heavier objects fall faster”

Without air resistance, objects of different masses would fall with the same acceleration. In daily life we see a difference because air slows light, wide objects more. We told the history and the experiment in a separate post.

3. “Plants take their food from the soil”

In the 17th century the Flemish physician Jan Baptista van Helmont carried out an experiment: he planted a willow sapling weighing about 2 kg in a pot holding about 90 kg of soil and watered it with only rainwater for five years. The tree grew to about 77 kg; the mass of the soil dropped by only a few tens of grams. The plant’s mass had grown far more than the loss of soil could account for. Today we know that most of a plant’s mass is built from carbon dioxide in the air and from water through photosynthesis; from the soil the plant takes mainly water and small amounts of minerals. See our photosynthesis post for more.

4. “Heat and temperature are the same” and “metal is colder”

A metal spoon and a plastic spoon standing in the same room have the same temperature; but because our hand loses heat to metal faster, we feel the metal as colder. Temperature is a quantity related to the average energy of the particles’ motion; heat is the energy transferred because of a temperature difference. You can study this in our heat and temperature lesson.

5. “Current is used up in the bulb”

In a simple circuit the current is the same before and after the bulb. What decreases in the bulb is not the current but the energy carried by the charges; this energy is turned into light and heat. In a series circuit the current stays the same at every point. This difference is covered in detail in our series and parallel circuit post and series circuits lesson.

6. “Earth’s shadow causes the Moon’s phases”

The idea we started with. Half of the Moon is always lit by the Sun; the phases come from the changing angle of the Sun-Earth-Moon triangle. You can see this step by step in our Moon phases post and Moon phases lesson.

What helps change a misconception?

Posner, Strike, Hewson and Gertzog (1982) proposed that four conditions are generally needed for a student to give up an old idea and accept a new one. The student must:

1. Be dissatisfied with the old idea (meet a situation it cannot explain),
2. Be able to understand the new idea,
3. Find the new idea plausible,
4. See the new idea as fruitful (able to answer new questions).

This framework turns into a few suggestions that can be used in class:

• Bring the idea out first. Ask the student for a prediction and a reason. The predict-observe-explain method suits this.
• Show a situation where the old idea fails. A question such as “If we are closer to the Sun in summer, why is it winter in Australia?” creates dissatisfaction.
• Put the model in their hands. A student who shows the Moon’s phases with a ball and a lamp gains a different understanding from one who memorises the rule.
• Repeat. An idea corrected once may not stay corrected; come back to the same concept weeks later (see our spaced repetition post).
• Do not belittle the misconception. Saying “it is very natural to think so, because that is how it looks in daily life” opens the door to change.

An honest note: no method guarantees that a misconception disappears in one go. The aim is therefore not to “punish” the misconception, but to help the student test and reconsider their own idea.

Summary

• Misconceptions are not random mistakes; they are regular, lasting ideas born of everyday experience.
• Seasons, falling objects, plant food, heat and temperature, current and Moon phases are common examples.
• Change needs the idea to be made visible first, then tested, and the new model to be used.
• Instead of a single explanation, prediction, observation and spaced repetition work together.

For teachers who want to try these in class, the Teachers page is ready, and for those who want to look at lessons with simulations, there are the Science topics.