An internet poster recently floated the idea that friction with a recently denser interstellar medium causes global warming. Despite its superficially ridiculous nature, refuting this proposition is an interesting quantitative exercise.

The purpose of this article is to provide teachers of science scientific definitions and illustrations to facilitate the teaching of cosmology. Secondary school science teachers can use the illustrations and their citations to pose questions to their students and to guide their students to accessible digital sites where the students can explore…

The present work refers to a study of 10-12-year-old students' ideas on the self- or hetero-luminosity of the Moon. To check the validity of students' reasoning on this question, we also examined their ideas on the lunar phases and how we see hetero-luminous objects. Students supported their ideas on the self- or hetero-luminosity of the Moon by…

We study the variation of the apparent weight of an object with height above the surface of a planet with a (buoyant) atmosphere. Interestingly, this variation depends on two competing factors--the reduced gravitational acceleration (which acts to reduce the weight with increasing height) and the reduced buoyancy force in the progressively less…

The Sun does not return to the same position in the sky every 24 hours. At local noon, for example, the Sun will appear higher in the sky as we move from winter to summer solstice. In addition, and perhaps more surprisingly, solar days (the roughly 24 hours between subsequent local noons) vary in length, causing the Sun to be east or west of its…

We present two studies to investigate the extent to which attending a planetarium presentation increases secondary school students' understanding of the apparent motion of the Sun and stars. In the first study, we used the Apparent Motion of Sun and Stars (AMoSS) test in a pretest/post-test/retention test setting to measure learning gains and…

Knowledge about the interior density distribution of a planetary body can constrain geophysical processes and reveal information about the origin and evolution of the body. Properties of this interior distribution can be inferred by analyzing gravity acceleration data sampled by orbiting satellites. Usually, the gravity data is complemented with…

Many research studies have shown that lower-secondary school students' scientific literacy depends on their understanding of corresponding scientific concepts. Therefore, it is of great significance to model and assess students' conceptual understanding in learning specific scientific concepts, because it can reflect and diagnose students'…

Microteaching is a significant way to prepare pre-service teachers to overcome specific challenges in a natural classroom environment. It is widely accepted that pre-service science teachers gain pedagogical benefits from microteaching activities. Furthermore, microteaching enhances the conceptual understanding of the presenter on the related…

In today's world, where technology is advancing day by day and it is easier to access information, developments in science bring along a process that involves dilemmas regarding the ethical and moral values of individuals as well as providing basic scientific knowledge to society. Space exploration refers to a perspective that examines the social,…

Even though many physics teachers take their students on a calculation adventure through circular motion and Newton's universal law of gravity to determine Earth's velocity, most of us leave it at that. We present the final result and say, "Look, Earth is moving around the Sun at about 107,000 km/hr (66,000 mph), yet we can't feel the motion…

The concept of redshift is very often used in teaching physics and astronomy, as well as in science public outreach. Redshift is an interesting topic, used to describe many physical processes such as the Doppler effect or the expansion of the universe. Nevertheless, there are unfortunately also misconceptions about redshift. When facing the…

The falling temperature of the photosphere with height is responsible for the effect known as limb darkening. The Sun is not equally bright all over the disc. When we observe the Sun towards the limbs, it appears to get darker. Light from the photosphere travels through an absorptive medium. Therefore, one can see only so far into the photosphere.…

The acceleration of gravity in Earth's interior is determined by the density distribution in Earth. A remarkable result is that the acceleration is approximately constant all over the mantle, which amounts to about 84% of Earth's volume. This result can be explained by a simple two-layer model of Earth, showing that the constancy of the…

In the last decades spectroscopy began to play an essential role in physics education research with the recognition that atomic spectra constitute a good occasion to study the concepts of quantum mechanics. Moreover, activities in which atomic spectra are studied in order to understand star structure and evolution have proved particularly engaging…