It’s Sunscreen Season!


Beach season is upon us, Northern Hemisphere! We wish you sun-filled, happy days, and healthy, sunburn-free skin! Here are some tips for choosing a sunscreen for your summer.

Sunlight is composed of electromagnetic waves and is our primary source of ultraviolet radiation, which has a shorter wavelength than visible light and carries more energy. UVA, UVB, and UVC are classified according to their wavelengths. Short wavelength UVC never reaches the Earth’s surface, but UVB and UVA do Medium wavelength UVB rays can enter the skin’s superficial layers and long length UVA rays can penetrate into the deeper layers. UVB in small amounts actually helps us make vitamin D, which enables our bodies to build and maintain strong bones. However, prolonged exposure to UVA and UVB can damage DNA, age your skin, and promote the development of potentially deadly skin cancer. Sunscreen protects your skin either physically by deflecting UV rays with an inorganic blocker like zinc oxide or titanium dioxide, or chemically by using carbon-based compounds to absorb UV photons that are then harmlessly dissipated as heat.

So, what differentiates one sunscreen from another? When we choose a sunscreen, we can compare application method, the SPF, and the active ingredients. Sprays can be convenient to put on, especially when you’re wet, but a recent study found that most people don’t apply a thick enough layer to get full protection. And the possible health risks of inhaling sunscreen compounds from a spray cloud might make you consider reaching for that bottle of lotion instead. Opt for a sunscreen with an SPF of at least 15, although 30 is better. SPF is a nonlinear scale of how much UVB radiation is needed to give protected skin a sunburn. SPF 15 does a pretty good job by blocking 93% of UVB rays. You get a slight increase as SPF goes up, with SPF 30 blocking 97%, and 50 blocking 98%. SPF is based on the quantity of solar exposure. So how much time you have before you start to burn really depends on a long list of factors, including your genetics, and when, where, and how you spend your time in the sun.

Even though US marketed sunscreens have been deemed safe by the FDA, scientists are still researching the effects of many active ingredients on the human body. So if you’re worried about potential irritants, look for mineral-based formulas with zinc oxide or titanium dioxide. Even though they may go on a bit thick at first, they’re less irritating than carbon-based chemical sunscreens. These mineral-based sunscreens are preferential for the environment, too. If you plan on catching rays while splashing in a river or the ocean, keep in mind that carbon-based chemical sunscreens can harm marine life. Research shows that carbon-based chemical sunscreen ingredients, like oxybenzone, butylparaben, octinoxate, and 4MBC contribute to a stress condition called coral bleaching in corals, which are living creatures. 

So you’re now ready to make an informed choice when picking out your next sunscreen. SPF is clearly labeled on the front. On the back under “active ingredients,” you can find whether zinc oxide, titanium dioxide, and those coral-harming components are present. Taking a bit more time to check can be well worth it for both you and the environment.

From the TED-Ed Lesson Which sunscreen should you choose? – Mary Poffenroth with animation by Rob Kohr & Travis Spangler

Additional artwork & info from the TED-Ed lesson Why do we have to wear sunscreen? – Kevin Boyd with animation by Andrew Foerster

Happy Summer, Tumblr! Sunbathe safely!

What does it mean to be a refugee?



About 60 million people around the globe have been forced to leave their homes to escape war, violence and persecution. Those who have crossed a border and sought shelter outside of  their  own  countries–and  they  are  commonly  referred to as ‘refugees’, but what exactly does that term mean? The world has known refugees for millennia, but the modern definition was drafted in the UN’s 1951 Convention Relating to the Status of Refugees in response to the mass persecutions and displacements of the Second World War. It defines a refugee as someone who is outside their country of nationality, and is unable to return to their home country because of well-founded fears of being persecuted. That persecution may be due to their race, religion, nationality, membership in a particular social group, or political opinion and is often related to war and violence.


So what happens once someone flees their country? Most refugee journeys are long and perilous, with limited access to shelter, water or food. Since the departure can be sudden and unexpected, belongings might be left behind. And people who are evading conflict do not often have the required documents, like visas, to board airplanes and legally enter other countries. Financial and political factors can also prevent them from traveling by standard routes. This means they can usually only travel by land or sea and may need to entrust their lives to smugglers to help them cross borders. 


Each refugee’s story is different, and many must undergo dangerous journeys with uncertain outcomes. Today, roughly half of the world’s refugees are children, some of them unaccompanied by an adult; a situation that makes them especially vulnerable to child-labor or sexual exploitation.


Chances are if you go back in your own family history, you will discover that at a certain point your ancestors were forced from their homes, either escaping a war or fleeing discrimination and persecution. It would be good of us to remember their stories, when we are hearing those of the people currently displaced, searching for–or on their ways to– a new home.

Today is World Refugee Day and the UNHCR is launching its #WithRefugees petition to send a message to governments that they must work together and do their fair share for refugees. The #WithRefugees asks governments to ensure every refugee child gets an education, that every refugee family has somewhere safe to live, and that every refugee can work or learn new skills to make a positive contribution to their community. We hope for a world where violence will not force people from their homes, but until then, let the world know you stand #WithRefugees.

From the TED-Ed Lesson What does it mean to be a refugee? – Benedetta Berti and Evelien Borgman

Animation by TED-Ed and @j-vuylsteker

My first code in Mathematica goes back to V2 (…

My first code in Mathematica goes back to V2 (1991) for the first reliable graphical environment from Microsoft (Windows 3.0, 3.1), lab reports improved instantly. Many things have changed in three decades in the world of computer algebra systems, even to the point to be of (irremediably) minority use, mostly because there are plenty alternatives both for high (Matlab, Octave, Sage) and low level (C, C++, Fortran…), or both (Python, Java, R…). But for people of a couple of generations (those born in the 60s and 70s or so) coming from an almost purely analogical world, seeing a pioneer (back then and now) of that generation as Stephen Wolfram (1959), posting this about the software that he himself had developed from the scratch before his 30 birthday, well, it makes us… happily nostalgic.



“Like elsewhere in the colonies, the colonial representation of Jamaica and Jamaicans was typically reductive and exoticized. These stereotypes took on their modern form in the context of early tourism, as is exemplified by the ‘native market woman’ or ‘native man with a donkey cart’ imagery in the late nineteenth- and early twentieth-century photographs, postcards and illustrations.”

— Veerle Poupeye. Jamaican Art and Changing National Imagery: From the Affirmative to the Critical. (via alynaomie)

lea–krawczyk: Last summer i’ve made a co…


Last summer i’ve made a commissioned film for TED-ed lessons ! What a great experience. It’s about the myth of Prometheus. You can check the film here :

Here are some color researches !

We love when artists share their behind-the-scenes of TED-Ed Lessons! 

Here, Léa Krawczyk shares her color studies for her beautifully designed animation on the The myth of Prometheus!

Check out Léa’s tumblr for more behind-the-scenes and her other stunning illustration + animation work.

From the TED-Ed Lesson The myth of Prometheus – Iseult Gillespie

Animation by Léa Krawczyk ( @lea–krawczyk )

In her short life, mathematician Emmy Noether …

In her short life, mathematician Emmy Noether changed the face of physics:

About the David Hilbert’s answer to opposers to Emmy Noether’s application for the position of Privatdozent at University of Göttingen, the full quote goes:

“I do not see that the sex of the candidate is an argument against her admission as privatdozent. After all, we are a university, not a bath house.”

Noether’s application was rejected anyway, but Hilbert arranged for her to stay at Göttingen by having her lectures announced under his name. [See here or here]

samanthalynch134: 2014// 2018


2014// 2018

nickisxminaj: APES**T – THE CARTERS





yoncehaunted: APES**T – THE CARTERS