Category: Science

En snabbkurs i homeopatiska läkemedel

En liten snabbkurs i homeopatika från Der Spiegel, tips från Orsakverkan (Twitter).

D1 betyder att lösningen är spädd med en del av den aktiva ingrediensen och 9 delar vatten. D2 betyder att en D1 lösning är spädd på samma sätt, så att en hundradel av lösningen är den aktiva ingrediensen. Siffran talar alltså om hur många nollor du ska ha i faktorn. D1 betyder 1:10. D2 betyder 1:100. D3 betyder 1:1000. D9 betyder 1:1 miljard, alltså ungefär som en droppe av den aktiva substansen i en tankbil. D78 betyder att av alla molikyler som finns i hela universum, är några stycken från den aktiva ingrediensen. Enligt Der Spiegel används lösningar upp till D1000 i Tyskland. Vågar man påstå att homeopater säljer dyrt kranvatten?

Du som inte redan följer Pekkas blogg, Orsakverkan, hittar den här.

My bits on evolution, part 1

Some of my bits for the Swedish Skeptic Podcast, Skeptikerpodden, on evolution and creationism, in Swedish.

Några av mina bidrag till svenska Skeptikerpodden om evolution och kreationism, på svenska.

1. “Evolutionism” (från Skeptikerpodden 31/3 2010)

2. Kreationistiska falanger (från Skeptikerpodden 12/4 2010)

3. Bevis för evolution (från Skeptikerpodden 3/5 2010)

Swedish woo-woo map

This is the Swedish woo-woo map on Google Maps. Please help updating it, and do consult it to make sure you’re not paying for any nonworking preparations or other bogus.

Noah’s calculator found!

Recently, we have read about some insane adventurers who have found NOAH’S ARK! Yes, the boat that Noah used to survive the flood together with seven pairs (14 animals) of each “clean” species (or bird) and one pair of each “unclean”. As you might guess, this is a huge project. The collecting itself must have been exhausting. However, now we have found his calculator!

Download it here.

Vad är vetenskaplig skepticism?

Första avsnittet av Skeptikerpodden är nu publicerad. Saxat från Skeptikerpodden.se:

I vårt premiäravsnitt förklarar vi vad vetenskaplig skepticism är för något och diskuterar folks reaktioner på uttrycket. Vi diskuterar en nyhet om en ny människoart och några av bristerna i nyhetsrapporteringen kring detta. Magikern Gaston intervjuas och han får förklara sin syn på skepticism. En liten överraskning från James Randi lurar också i programmet. Mycket nöje!

Jag ser fram emot att jobba vidare med detta projekt.

Radiometric dating, why do we trust it?

You just got to love the YouTube user cdk007. In his (at this point) latest video, he spends 10 minutes to explain how radiometric dating to a hypothetic creationist, adding the objections you would expect from a creationist. If you ever hear the argument that radiometric dating doesn’t work (assuming that we don’t know how atoms work), get them to watch this! Or at least, make sure you know the correct answer to the following question:

How do we know that we actually can trust radiometric dating?

Teodicéproblemet

Hur fungerar detta nu igen?

Some visual aid

To conclude, click on an organism to zoom in on it. When an organism is zoomed in, some details about it is shown together with the DNA string of the parent organisms (if the parents are still alive).

Download: Drifting.exe

Happy new year!

If you are interested in looking at the source code, a VS2010 Visual Basic solution can be downloaded here. The solution targets .NET Framework 2.0.

Counting the DNA differences

The following adjustment is done to the drifting game. In the first version, DNA differences were counted sequentially, meaning that within each group each organism was compared to its neighbor. By changing this so that every organism is compared to every other organism, and then divided to the number of comparisons done within each group, the number of DNA differences within each group is much more accurate. This makes the increasing differences, the drifting, much more obvious.

The screenshot displays the number of differences just a few years after separation of the groups.

Download the drifting game here.

This is the drifting game!

The drifting game does not illustrate evolution or the power of natural selection, but change over time and our ability to tell that about relationship to other spices, such as chimpanzees. The board consists of 285 placeholders (19 x 15). Each placeholder can hold one organism. This is an organism.

The blue number indicates the age in years of the organism. The red number shows the number of offspring the organism has produced. An organism cannot produce offspring on its own; it must mate with another organism of the opposite gender. Light blue rectangle represent male organisms, pink represent female. What else? ;-) The lines are drawn between parents with the child in between.

In the middle, the DNA of the organism is displayed. The red amino acid pairs with red or yellow amino acid. The green amino acid pairs with green or blue amino acid. A DNA string consists of 24 pairs. The effect of this demonstration will be better if the number of pairs is greater, but it makes the visual overview poorer.

When organisms breed, the offspring will have a mixture of the parents DNA. Sometimes, mutations occur. Mutations cannot be traced from either parent. A mutation can sometimes be easy to spot, because in a mutation, any amino acid can pair with any amino acid. So a red could pair with a red, but it could also pair with a green. A pair of red and yellow could be a mutation, a pair of red and green is a mutation.

An organism that isn’t too young or too old might breed and an organism of high age might die and leave room for younger individuals.

To control: Press Space to pause and press F12 to separate the group in to two groups (can be done once). The expected effect after the split is that the number of DNA differences between individuals in the group will remain the same as the previous total, but the DNA differences between the groups will increase over time, even though no selection is done. The DNA differences are counted for sequentially and divided by the number individuals in a group. So, not every individual is compared with every individual. Correction here.

Before the population is splitted into two groups (press F12 to do that), the total number of DNA differences is shown. After the population is splitted into two groups, the total number of DNA differences is shown together with the number of DNA differences within each group. Now you can compare the differences within each group (expected to be smaller) with the total number of differences (expected to be larger since the groups are drifting in different directions).

Download the drifting game here.