Will a bowling ball fall faster than a feather?

Listen to this:

If you dropped a feather and a bowling ball at the same time, which would hit the ground first? You would probably say that the bowling ball would hit the ground first, right? After all, a bowling ball is so much heavier.

It turns out that the relative weight of the objects doesn’t make a difference to which object will hit the ground first, as strange as that may sound.

One of the parents in our class chat group shared this terrific video from the BBC that explains what really makes a difference and, surprisingly, that a bowling ball and a feather will hit the ground at the same time under the right conditions:

So, as you can see, the factor that makes the difference in normal conditions isn’t the objects’ weight, it’s air resistance! When you remove the air, both objects fall at the same rate and hit the ground at the same time.

Image credit: Pixabay

What happens when lightning strikes an airplane?

This morning our daughter asked me what happens when lightning strikes an airplane. She is a little afraid of storms and she was concerned about the passengers of airplanes when there are lightning strikes.

Understanding lightning better

Lightning is, at the same time, an awesome and terrifying phenomenon. It seems to affect us on a very primal level. Understanding it better helps us appreciate its awesome beauty while making sure we are safer during lightning storms. I found a great video from SciShow Kids about lightning:

National Geographic also has a great video that explains lightning:

Lightning moves pretty quickly so we don’t always see lightning in more detail. I found this terrific video on Wikipedia (your browser may not play the video if it doesn’t support .ogv formats).

So what happens when lightning strikes an airplane?

The prospect of lightning striking an airplane can be scary. I was fascinated to learn that planes are engineered to handle lightning strikes in an interesting way. Here is a video from the Smithsonian Channel:

If you are interested in reading more about how airplanes are engineered to withstand lightning strikes, also read an article on Scientific American titled “What happens when lightning strikes an airplane?”. Here is an extract from the Scientific American article that answer my daughter’s questions about passengers’ experience of a lightning strike:

Although passengers and crew may see a flash and hear a loud noise if lightning strikes their plane, nothing serious should happen because of the careful lightning protection engineered into the aircraft and its sensitive components. Initially, the lightning will attach to an extremity such as the nose or wing tip. The airplane then flies through the lightning flash, which reattaches itself to the fuselage at other locations while the airplane is in the electric “circuit” between the cloud regions of opposite polarity. The current will travel through the conductive exterior skin and structures of the aircraft and exit off some other extremity, such as the tail. Pilots occasionally report temporary flickering of lights or short-lived interference with instruments.

Thunderstorms are impressive and powerful natural phenomenon and it’s usually a good idea to keep your distance, regardless of your mode of travel. At the same time, it is good to know what even when you are suspended in the air, traveling through a storm, you are probably safe.

Featured image credit: Pixabay

Better storm prediction by knowing more about raindrops

The GPM satellite studying raindrops

Listen to this:

Did you know that knowing the size of raindrops in clouds can help meteorologists more accurately predict rainfall? A new joint American and Japanese mission promises to help scientists make even more accurate predictions based on the size of the raindrops in clouds. This next video is a great overview of the mission:

According to NASA’s Goddard Media Studios blog post titled “GMS: Why Do Raindrop Sizes Matter In Storms?”:

Not all raindrops are created equal. The size of falling raindrops depends on several factors, including where the cloud producing the drops is located on the globe and where the drops originate in the cloud. For the first time, scientists have three-dimensional snapshots of raindrops and snowflakes around the world from space, thanks to the joint NASA and Japan Aerospace Exploration Agency Global Precipitation Measurement (GPM) mission. With the new global data on raindrop and snowflake sizes this mission provides, scientists can improve rainfall estimates from satellite data and in numerical weather forecast models, helping us better understand and prepare for extreme weather events.

If you are curious about the spacecraft that is conducting this amazing survey work, here is a helpful explanatory diagram:

The GPM spacecraft

Here is a great video that explains how the size of raindrops can help better understand storm behaviour:

A transcript of the video is here.

NASA also published a great comic for kids about the mission titled “Raindrop Tales – GPM Meets Mizu-Chan” which you can download and print or read online.

NASA’s GPM mission site has a wonderful collection of videos, images and other information about the mission. Another great video is this one titled “NASA | GPM: One Year of Storms”:

This is a fascinating mission. I didn’t realise just how much storm prediction can be improved by understanding how big raindrops are.

Marshmallows in a vacuum


Listen to this:

Hi everyone, its the mom here, with my first Stuff to Teach Our Kids post.

I really like baking, the kids like mixing and licking the bowl. I also like teaching them how and why we mix the ingredients together and the reactions that take place when certain things mix. Baking really is just science. So I went looking for some fun baking experiments we could try.

I came across this video by The Crazy Russian Hacker about what happens to marshmallows in a vacuum. It looks like a really fun experiment to try at home and you can find a vacuum box like the one he uses on Amazon here. You can also make your own vacuum box using a wine bottle and a wine saver pump/stopper (instructions here).

According to Physics.org the science behind the growing marshmallows is as follows:

Marshmallows have small bubbles of air trapped inside them. These bubbles are at atmospheric pressure. When the air inside the glass container is sucked out, the volume of the container remains the same although there is much less air inside – so the pressure is reduced. The air bubbles inside the marshmallows are therefore at a much higher pressure than the air surrounding the marshmallows, so those bubbles push outwards, causing the marshmallows to expand. When air is let back into the glass container, the surrounding pressure increases again, and the marshmallows deflate back to their normal size.

As soon as we get the vacuum boxes we are going to try this out for ourselves and I will post a video of our results. Please let us know if you try it out too.

Image credit: Marshmellows by Maryam Abdulghaffar, licensed CC BY 2.0

The Mars Reconnaissance Orbiter and it’s Mars mission

Mars Reconnaissance Orbiter

Listen to this:

One of the amazing vehicles humans have sent to Mars to explore the red planet is the Mars Reconnaissance Orbiter. What is the MRO? According to Wikipedia:

Mars Reconnaissance Orbiter (MRO) is a multipurpose spacecraft designed to conduct reconnaissance and exploration of Mars from orbit. The US$720 million spacecraft was built by Lockheed Martin under the supervision of the Jet Propulsion Laboratory (JPL). The mission is managed by the California Institute of Technology, at the JPL, in La Cañada Flintridge, California, for the NASA Science Mission Directorate, Washington, D.C. It was launched August 12, 2005, and attained Martian orbit on March 10, 2006. In November 2006, after five months of aerobraking, it entered its final science orbit and began its primary science phase. As MRO entered orbit, it joined five other active spacecraft that were either in orbit or on the planet’s surface: Mars Global Surveyor, Mars Express, 2001 Mars Odyssey, and the two Mars Exploration Rovers (Spirit and Opportunity); at the time, this set a record for the most operational spacecraft in the immediate vicinity of Mars. Mars Global Surveyor and the Spirit rover have since ceased to function; the remainder remain operational as of March 2016.

MRO contains a host of scientific instruments such as cameras, spectrometers, and radar, which are used to analyze the landforms, stratigraphy, minerals, and ice of Mars. It paves the way for future spacecraft by monitoring Mars’ daily weather and surface conditions, studying potential landing sites, and hosting a new telecommunications system. MRO’s telecommunications system will transfer more data back to Earth than all previous interplanetary missions combined, and MRO will serve as a highly capable relay satellite for future missions.

בעברית: בויקיפדיה

The official NASA MRO website also has a great overview of the MRO’s mission which you should read for more background information and links to more information about aspects of the mission.

I noticed a terrific video commemorating 10 years of the MRO’s mission which includes some wonderful imagery:


You can also find a huge gallery of high resolution imagery in the NASA JPL Photojournal that is worth spending some time exploring. Here are some examples:

Wind at work
The Ares 3 Landing Site: Where Science Fact Meets Fiction
Aeolian Features of Scandia Cavi

Image credit: Wikipedia (Public Domain)

Audio clips and a companion Facebook Page

I have some news to share with you quickly.

Audio clips

Firstly, I have added audio clips to each of the articles on the site with a short overview of what the article is about. It occurred to me that many of the kids who may visit the site may not be able to read and all the text would be lost on them. Here is an example:

Your browser does not support the audio element.

Please let me know if any audio clips don’t work for you? I used an HTML audio tag to embed the clips and the audio clips themselves are hosted on Amazon S3.

Now on Facebook

I created a companion Facebook page to go with this site and make these articles more accessible through the single biggest social network on this planet. I’m still deciding how to use Facebook best but, for now, I’ll share articles from this blog on the page and use Facebook to share quick updates too.

I have also added AMP and Instant Articles support for this site so articles should display that much better on mobile going forward.