Tag Archives: astronomy

Sun-Earth-Moon Interactions

Good afternoon,

While doing some site maintenance today, I realized that I never actually published several of my class notes presentations, which doesn’t really mesh with my Knowledge is Power philosophy: “I believe that the free flow of information leads to informed decisions, which create an open and equitable society.” Therefore, I’m publishing every class presentation I’ve ever created. Whenever I discover one that hasn’t been shared, I’ll add it to the appropriate class and unit pages, as well as writing a brief post about the presentation here.

Today’s slides are from an 8th-grade astronomy unit that I developed a few years ago, focused on the MYP science concepts of relationships, movement, interactions, and patterns, I hope you find it useful.

Happy learning!

Mr K

Astronomy resources for students

Good morning!

Today I’m doing a little site maintenance, incorporating as many digital resources as possible into the various science pages on my website. The resources include simulations, videos, and activities created by other teachers and educational institutions. Instead of linking this blog post to a bunch of bookmarks I’ve saved over the years, I’ll just suggest that you check out my astronomy page under the “Sciences” tab on my homepage.

Among the many dozens of resources I’ve added, I think you’ll find something educational, engaging, and entertaining for a wide range of audiences.

Happy learning!

Physics resources for students: part 1

Good afternoon!

Today I’ll share a few of the resources  I use to teach the fundamentals of physics. One of the most fun aspects of teaching physics is that it lends itself to so many entertaining and engaging activities and demonstrations in class. Along with chemistry, physics is probably the most hands-on science I teach; therefore, real-world demonstrations and activities are the bread and butter of my physics units. However, there are any number of situations in which hands-on demonstrations aren’t possible or feasible: a lack of funding or resources at a school, broken equipment, abstract concepts or perhaps a student is simply reviewing material at home. In these cases, animations can provide a tremendous amount of help in understanding the essentials of physics. Most of the resources I’ve listed here are collections of animations to help students learn (and teachers teach!) about physics.

Explore and enjoy! Happy learning.

Welcome to the new school year!

Welcome – or welcome back – to another exciting year of learning about science!

After recharging my internal batteries on an extended safari with my dad and brother, followed by a couple of weeks in Italy with my children and my mom, I’m energized for the upcoming school year. It’s time to get started on what should be an exciting, innovative, engaging year for myself and all the students in my classes.

We’ve overhauled the grade 8 science curriculum since last year, which means that this year we’ll be studying astronomy, chemistry, electricity and magnetism, and plant adaptations – a nice mix of sciences that will hopefully offer a little something for everyone.

Grade 10 science is broken into the three ‘classic’ sciences of chemistry, physics, and biology, with units on stoichiometry, sound and light waves, and genetics and evolution, respectively.

This year is particularly intriguing for me as I make the transition from teaching the Diploma Program’s Environmental Systems and Societies course for the past 7 years to my first year teaching IB Biology. It will be fun to apply some of my “teaching bag o’ tricks” to a new subject.

Let’s get started!


Mr K

Celebrating Women in Astronomy

In honor of International Women’s Day, I am focusing today’s lessons in grade 8 science on the many contributions of women to the field of astronomy.

We start with an overview, courtesy of The Woman Astronomer, with stories of women from Hypatia of Alexandria and the “Harvard’s Computers” to Debra Fischer and Jill Tarter. Students will examine how these women have influenced our knowledge of the heavens throughout history.

The Astronomical Society of the Pacific also has a nice collection of short biographies about women who have contributed to the field of space science.

Then we’ll wrap up class with a showing of Neil deGrasse Tyson’s Cosmos episode titled “Sisters of the Sun,” in which we explore not only the structure of the Sun and other stars, but the stories of Annie Jump Cannon and Henrietta Swan Leavitt.

Remember, every person on Earth owes his or her life to a strong woman – Mom!

The Value of Experiential and Outdoor Education

Good afternoon.

I just returned to Dar es Salaam from our school’s Extended Studies Program (ESP) – a “week without walls” – in Amani Nature Reserve of the East Usambara Mountains of Tanzania. The 8th-grade students who accompanied me got to experience one of my favorite parts of this country, a location rich with endemic plant and reptile species, as well as a climate and geography radically different from the hot, steamy coastal zone where we live.

During our time in Amani, we encountered quite a few unique creatures and plants, including forest cobras, Fischer’s chameleon, the Usambara 3-horned chameleon, pygmy chameleons, black-and-white colobus monkeys, 20 species of African violets, army ants, the pregnancy-test frog (really!), tree frogs, colossus crickets, swallowtail butterflies, forest moths, damselflies and dragonflies, trumpeting hornbills, the African fever-tree, and a lot more tree species than I can possibly remember. We also studied craters on the moon and watched Jupiter and its 4 Galilean moons climb across the night sky while we were in camp.

Apart from my personal interest in biodiversity, mountains, astronomy, and forests, there is real value in taking students ‘out there’ to see and experience a part of the world they might not otherwise visit. These kids live fairly posh lifestyles here in Dar, and putting them in tents for a week really stretches some of them. They develop a greater appreciation for the ease and comfort of home, and they confront – briefly – firsthand the challenges of living off the land in tropical Africa.

They also get to do things we can’t do in a classroom: feel the way a chameleon grips your skin as it climbs up your arm, observe the dark bands in Jupiter’s atmosphere, try to decipher the code of flashing firefly lights in pitch darkness, listen to owls call across a primary forest, chase frogs as they try to escape into chilly ponds and streams, and feel the microclimate changes in light, temperature, and humidity between tropical forest and farmland. Adding these first-hand sensory inputs reinforces classroom lessons and clarifies what may be highly abstract concepts for a lot of students who spend most of their days indoors. Plus, they’re just plain fun most of the time (apart from the army ants).

“What if I don’t believe in the Big Bang?”

Good morning.

During one of today’s lessons, I received an email from a student asking the question above. As a science teacher, I’ve encountered this question before, usually when we study evolution, but my response applies equally to other fields of science – not just biology. I think it’s important to remind students and families about the key difference between the scientific and spiritual realms, and we will address the student’s question in my class later this week. I’ve pasted my response to this student below, with the student’s name changed for privacy reasons.

Hi Mr Kremer.

I was just wondering, what if you don’t really believe in the Big Bang? What if you believe in another theory?
Thank you
Curious Clinton, 8Z
That’s a good question Clinton, and for a lot of people it’s a tricky one. Part of the confusion is based on use of the word ‘believe’ instead of the more appropriate words ‘observe’ and ‘measure’.  Beliefs don’t need observable, measurable evidence. Observation means using only what we can directly sense and measure.

Science is based on observation and study of the natural world. We come up with ideas to try to explain what we can observe, and then we design ways to test those ideas – scientific experiments. If the idea fails the test, we reject it. If the idea is supported by the test, we build on it and go deeper, adding more detail so that we have a more complete picture of how the idea/process works. We keep doing this over and over again, and we have other people test the same ideas, until one of 2 things happens:

  1. the idea fails a test, and we reject it as being ‘not correct’
  2. the idea continues to be supported by observation, and we continue to build on it

So within science, it’s not really accurate to say that we ‘believe’ in an idea like the Big Bang Theory, or evolution by natural selection, or gravity. Rather, we accept the evidence that supports these theories. These theories have been tested many different ways by many different people and have always been supported by observation – what we can see, hear, smell, or sense. That means we consider them to be true up to the moment when one of them fails a fair test. If one of them fails a fair test and is disproved, scientists will no longer accept the theory as a valid explanation for how the world works.

One classic example is our understanding of the structure of our solar system. Before people developed the telescope, which allowed us to directly observe the other planets and their moons, the Geocentric model (Earth at the center of the solar system, with the Sun and the other planets orbiting around Earth) was accepted as scientific fact because it passed all the tests available at that time. But once we invented telescopes and were able to accurately see that moons orbit around other planets and those planets orbit around the Sun, we recognized that the ‘Geocentric’ model wasn’t correct – it failed the test of observation. So we developed a new idea called the Heliocentric model, which has proven correct everything we have been able to observe so far.

At some point in the future, when we have better technology that lets us make even more precise and accurate measurements and observations about our Universe, we may decide that the Big Bang Theory is wrong. When and if that happens, we will reject the BBT and start using a new, better explanation for how the Universe began.

Does that help? It was a really good question, and we will talk about it in class soon.


Mr K

I’ll close with one of my favorite quotes from Neil deGrasse Tyson on this topic: “One of the beautiful things about science is that it’s true whether you believe in it or not.”