Aki's Blog

Diverse frågor och svar angående naturkunskap. 

Förklara begreppet ekologi.Ekologi är den vetenskap som beskriver samspelet mellan levande organismer och dess miljöer, till exempel hur de påverkas av överlevnadsfaktorer såsom näringstillgång, ljus, syre, naturliga fiender med mera. Kort sagt kan man säga att ekologi är vetenskapen om hur naturen fungerar utan människans inblandning.

Förklara begreppet art.Djur och växter brukar delas in i arter, det vill säga efter sina genetiska besläktningar. Oerhört många mindre arter är även besläktade med varandra så att man kan se stora likheter mellan till exempel hund och varg, även om de inte är av samma art.

Ge exempel på ekosystem i din närmiljö.Ett exempel på ett ekosystem bara hundra meter från mitt hem är ett närbeläget träsk i början av en mindre skog, där människan i princip aldrig träder sin fot. Träsket kryllar av grodor, insekter, ödlor och växter, och det är ett tydligt kretslopp där man äter eller äts. Grodorna och ödlorna lever till exempel på insekterna som själva bland annat tar varandra, eller små kryp vid vattennivån. Allt går nedåt i ett kretslopp där de minsta är näst intill osynliga, ett kretslopp av vad som verkar som hundratals arter.

Fotosyntesen är en kemisk process. Hur går det till? Varför kan man kalla det ett kretslopp?Fotosyntes är när växter med hjälp av färgämnet klorofyll och solenergi omvandlar koldioxid, som tas upp ur luften, till socker och syre. Det som skapas används antingen till tillväxt för plantan, eller som lagring – anledningen till varför vissa växter smakar sött. Syret som släpps ut efter processen andas bland annat av djur och blir åter till koldioxid, som åter igen tas upp och görs om till syre. Att detta återvinns om och om igen är vad som gör fotosyntes till ett kretslopp.

Vilka är producenterna, konsumenterna och nedbrytarna i fotosyntesen?Växterna som byggs starkare av energin är producenterna, djuren som äter dem (och även de som i andra ledet äter de djuren) är konsumenterna. När dessa dött tar nedbrytarna hand om resterna. De omvandlas då till koldioxid, vatten och växtnäringsämnen. Nedbrytarna är exempelvis bakterier, insektslarver, svampar, gråsuggor, spindlar och daggmaskar.

Förklara begreppet kolets kretslopp. Vad heter det med ett annat ord?Allt känt levande består bland annat av kol, som tas upp av växter i fotosyntesen i form av koldioxid, som då omvandlas till kolhydrater och syre. Koldioxid återförs igen genom bland annat djurens utandning, och när nedbrytarna tar hand om rester från döda. Sedan industrialismen har människan påverkar utsläppen av koldioxid grovt då förbränningen av organiska ämnen (i detta fall exempelvis kol, petroleum och naturgas) släpper ut enorma mängder koldioxid.

Eftersom allt är ett så kallat kretslopp så borde det ju vara okej att förbränna fossila bränslen. Är det det? I annat fall varför inte?Det är inte okej. Då jorden som sagt är ett kretslopp är det omöjligt att förinta någonting. Allt som ”förbrukas” återkommer, ingenting försvinner komplett. När människan gräver upp till exempel naturgas och förbränner det bildas koldioxid som aldrig kommer försvinna. Självklart fanns det även innan, men då djupt nere i jorden och hade ingen möjlighet att skada miljön. Se det som att släppa ut ett oövervinnerligt monster från dess igenstängda håla.

Beskriv hur en näringsväv fungerar.En näringsväv är i princip en näringskedja, vem som äter vem i en lång kedja med producenterna längst ned och toppkonsumenterna högst upp. En näringsväv visar hur olika gifter och näringsämnen sprids i djurriket genom att visa vem som hade det först och hur det spreds genom att djuret åts av ett annat.

Vad menas med att ett ämne är ett miljögift?Miljögifter är ämnen som inte passar in i ekosystemet och förstör för växter eller organismer när de sprids. Miljögifter är ofta väldigt stabila, vilket innebär att det tar lång tid för dem att brytas isär. Miljögifter kan vara antingen organiska (uppbyggda av kol) eller oorganiska, och kan antingen vara naturliga eller konstgjorda, skapta av människan.

Hur påverkas toppkonsumenterna i en näringsväv när det är miljögifter inblandat?Även om bara ett djur i en näringsväv åtar sig ett miljögift, påverkas enkelt många andra i näringsväven. Exempel: Om djuret – i detta fall kan vi ta exemplet en insekt – blir uppäten av en fisk överförs giftet till denne. När fisken i sin tur äts av en större fisk, som kanske är toppkonsumenten i kedjan, överförs miljögiftet dit.

Vilken betydelse har fjällämlarna i den svenska naturen?Fjällämlar är ett bra exempel på ett bytesdjur som rovdjur är ytterst beroende av. Om det finns väldigt få fjällämlar skulle färre rovdjur få mat och de skulle inte kunna föröka sig lika mycket. Med andra ord sjunker antalet rovdjur med antalet fjällämlar, och likaså ökar de tillsammans med. Vår naturs mångfald är med andra ord ytterst beroende av fjällämlar.

Vilka faktorer avgör antalet individer i ett ekosystem?Mängd föda (växter, bytesdjur, vatten med mera), organiska fiender (rovdjur), miljögifter, klimat (om det är en ovanligt kall vinter exempelvis). Människan kan också vara en viktig faktor – om det är jaktsäsong, om människan söker nya boplatser och måste undanröja skog för detta, etcetera.

“You see, wire telegraph is a kind of a very, very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? And radio operates exactly the same way: you send signals here, they receive them there. The only difference is that there is no cat.

- Albert Einstein

“I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones.”

-Albert Einstein

In a dinousaur (velociraptor) attack, someone (I don’t know who) got his head bit of. Then the dinosaur ran away laughing. My mother, Karin and I were standing chocked as we saw the head jumping back on to his head again, and him turning back to life. Karin and I ran away to explore the phenomenon closer, slowly realising that humans through evolution has learned to have their heads returned to them if they’re decapitated. We ran back to mom and asked her where the man with the head was. She answered that she had burnt his body as she didn’t think he had survived, even when he yelled at her to stop.

A short essay on Charles Darwin and the Theory of Evolution.

The Life of Charles Darwin

One of the most well-known names in the science of today is Charles Darwin, often called the Father of Modern Biology. He is the author of “On the Origin of Species” (1859), and the accredited discoverer of the Theory of Evolution, which during the second half of the 19^th and the first half of the 20^th century grew to become accepted as the origin of species, opposing Creationism, the theory that God would have created all living beings as they are today and always will be, and that we weren’t developed stage to stage in millions of years. He was not as many believe the first pioneer on the topic, however; he was merely the man who came with good evidence for the theory which could lead to its acceptance in scientific circuits.

Charles Darwin was born in 1809 as the son of Robert Darwin, and named after his uncle, a doctor who died after accidentally cutting himself during an autopsy. Robert first planned his son to follow in his uncle’s footsteps and become a doctor too, but Darwin refused when he realised he couldn’t stand seeing the pain in a patient during an operation – this was long before the invention of anesthesia.
After studying at Cambridge, Darwin decided to go with Captain Robert FitzRoy on a journey on the ship HMS Beagle, on which he investigated the life of animals on different islands in South America. This was where he first started developing his theory of evolution through natural selection that would contradict Creationism and change mankind’s view on biology.

The Theory of Evolution and Natural Selection

According to Darwin’s theory of evolution, the species of our world were not created as they are today, as believed earlier, but descend from common ancestors that can be very different from the descendants. Through generations, these evolve through what he called natural selection, allowing them to adjust to the environment in order to survive and reproduce. For example, the human of today received her fifth finger, the thumb, through evolution, to be able to use tools which we today need for our every-day life.

The basic of the Theory of Natural Selection reads as follows:

· The prime goal for every species is to survive and reproduce, passing on its DNA, which is unique for the species, unto its next generation.

· This results in too many organisms, and decreasing nourishment available. Thus, the competition between the individual organisms increases, and the weakest will not survive.

· The organisms that died are not random, but a chosen collection of the weakest; or in better words the ones that were not suited for the environment, while the organisms suited survived. Herbert Spencer called this by the well known phrase “survival of the fittest”, inspired after reading Darwin’s book On the Origin of Species.

As a result, only those suited for the environment live on. After many generations of evolution, those left are better suited. This can take a very long time, and the weaker species as well as unnecessary limbs of organisms, functions, etcetera, can linger for thousands of years before being removed. For example, the human appendix, a part of our digestive system, is theorized not to be used for anything anymore. It is therefore believed that it is only a matter of time before we are no longer born with an appendix. The same goes for our little toe, which we no longer need to use for balance. It is not unlikely that we by time only have four toes per foot.

Questions and answers on DNA. Quite boring reading, I know, but it might help someone I guess.

- What is DNA?
The DNA of an organism is the material showing its heredity. The DNA is mostly located in the cell nucleus, packed in chromosones, but can also be found in the mitochondria.

- What is the composition of DNA?
The building blocks of DNA are called nucleotides, and are made up of a phosphate group, a sugar group and four nitrogen bases. These are linked in order to build what looks like a  stair. The four nitrogen groups alternates on each step, as do sugar and phosphate; in other words will the composition on four steps in a row be sugar – nitrogen 1, phosphate – nitrogen 2, sugar – nitrogen 3, phosphate – nitrogen 4.

- What are the properties of DNA?
DNA is used to produce proteins, which are very important to an organism as it does most work within it. That the DNA can replicate itself results in new strands of DNA often showing up.

Lab Report on Energy

Anton Johansson, 9E

2. The Light Bulb and the Plates

2.1 Planning

2.1.1 Description of Lab

The second lab on thermal energy was to understand how fast light emitted thermal energy to objects around – in this case three plates of different colour.

                      The light bulb is to be placed in the middle of the three plates – one silvery, one black and one white – from the same length (10 centimeter). On the back of every plate, we will have taped a thermometer. We will then turn the light bulb on, and every minute (starting when we have just turned the light bulb on, recording this as after 0 minutes) check the temperature and note this down so we later can analyse the results.

                      As soon as we are convinced that the plates have reached their top temperature, we will turn the light bulb off and analyse the drop of temperature for a while.

2.1.2 Equipment and Materials Needed for Lab

·           Nearby electricity for the light bulb

·           Light bulb

·           Timer

·           Holder for the three plates

·           Three thermometers (and tape)

·           Pen and paper for noting results etcetera

2.1.3 Diagram of the Equipment’s Set Up

See page 3.

2.1.4 Hypothesis

I believe that the three will begin on about the same temperature (experience tells me that there’s always an error making one start on one degree higher or lower because of for example miscalculation, bad measuring on the length between the light bulb and the plates, etcetera), and have their temperatures increased steadily. I think that the black plate’s temperature will increase faster, as black is a colour that easier attracts thermal energy. As silver reflects thermal energy more, I think the silvery plate will not be as affected. The white will probably stand somewhere in the middle, as I’m not familiar with anything special about that colour (associated with thermal energy).

Of course we have to consider that everything works totally correct for having these results. The main impact on the results is probably bad timing – if someone is late checking the temperature or similar. As explained earlier, there’s always something that goes wrong. It can also be that we measure wrongly and that one of the plates is to far away from the light bulb, resulting in temperature increasing slower. There’s not really a way to avoid these errors but to be extra careful – check everything twice.

2.2 Performance & Conclusion

2.2.1 Results

See page 4 and 5.

2.2.2 Conclusions

All three of the plates turned out quite similar (as expected). At first, both the silvery and the black started at 21 degrees Celsius and the white started on 22 (probably because of an error, see section 2.1.4 for more information). After four minutes, all three of them had somehow gotten to 24 degrees. After six minutes, we turned off the light bulb, so a few minutes after that the temperature started to decrease. All of them were on different numbers when we stopped the lab, after five minutes; silver on 22, black on 21 and white on 23.

                      I had expected the silvery plate to be much less affected, but still it actually increased and decreased much quicker than the white, which I had expected more so of. Though, as expected, this was the one who didn’t warm up as much as the others (as I had expected),

                      The black plate was the most reactive to the thermal energy, quickly raising in temperature and reaching the highest in the middle – 25 – as well as the lowest in the end – 21. This was expected in my hypothesis, as I already knew how attracting black is. In the end (minute 12-14) it jumped from 21 to 22 degrees, and then back to 21. This is for an unknown reason that I cannot understand at all. Probably it was just a miscalculation, or minor changes in wind, room temperature or similar.

                      The white plate truly was the most boring one. As already pointed out, it started on 22 degrees for an unknown reason. It then was the only one to only jump one degree for the first minute. It stayed on 23 for one minute, and then changed into 24 to stay there for seven minutes, then turning back into 23 for the rest of the time. White took the role that I thought silver would have, being barely effected by the thermal energy at all – only taking skips of one degree at the time, without having time to cool down to less than 23 degrees before we finished the lab.

Lab Report on Energy

Anton Johansson, 9E

1. Water and Insulation

1.1. Planning

1.1.1 Description of Lab

What change of temperature drop will there be if the object is insulated differently? This question was to be answered as the lab was made. A bottle of water is warmed up with a bunsen burner, and the water is then poured into two different tubes, one normal glass tube and one insulated with styrofoam. The both tubes’ temperatures will then be checked with continuality every sixty seconds for ten minutes. The numbers will then be listed in a table steadily showing the way down for both temperatures.

1.1.2 Equipment and Materials Needed for Lab

· Bunsen burner to boil the water

· Glass bottle to boil water in

· Holder for glass bottle

· Two equivalent glass tubes

· Holder for the two tubes

· Two high temperature thermometers

· Tong for the glass tubes

· Pen and paper for noting results etcetera

1.1.3 Diagram of the Equipment’s Set Up

The equipment for the lab is to be set up as follows on the diagram shown below. The bunsen burner is placed under the holder for the glass bottle filled with water. As the water is boiling, the next step is then to pour the liquid into to tubes, both placed upon each holder, one tube being insulated. This is marked as “2″ on the diagram.

1.1.4 Hypothesis

My prediction of the results for this lab would be that the both temperatures will fall pretty steady, with about five degrees Celsius per minute, but that the non-insulated tube’s temperature will fall with a couple of more degrees than the insulated. The insulated easier keeps the temperature as Styrofoam is an object that is worse leading energy than air, that revolvs around the other tube. As energy is equal to warmth, it means that air easier brings away the heat, and therefore that the tube that’s not insulated will have a temperature which drops in degrees faster. Summary of my hypothesis, then: the both tubes will start at the same temperature (about 90 degrees Celsius, I believe, as it was boiling only seconds before) at 0 minutes. As the time goes, the temperature of both will drop steadily, but as the non-insulated tube’s drops with about five degrees, the insulated’s drops with about three degrees on the same time, because of the Styrofoam’s worse energy leading capacity.

1.2. Performance & Conclusion

1.2.1 Results

See the attachment.

1.2.2 Conclusions

The black tube had a temperature which steadily dropped from beginning at 0 degrees Celsius to have reached 45 degrees after ten minutes, which was the highest drop. As for the others, the temperature dropped heavily on the first step, as the water temperature adapted to the sudden change of temperature (when the heating thermal energy of the Bunsen burner was taken away), and in this case the drop was five degrees, which also was a record for the lab. Another heavy drop was recorded between the second and third minute, six degrees, but after that the drop was steady with one or two degrees per minute.

Together with the black tube, the shiny tube was the only to have a temperature starting on 64 degrees (that the others weren’t was probably a miscounting, or that the other tubes were filled with water too much later). Here as well as for the black tube, heavily drops of temperature were made in the beginning, even though the first minute’s drop isn’t as large as the black’s first, being three instead of five degrees. Something interesting later developed as the temperature stayed the same (56 degrees) for three minutes (4 – 6), till it dropped two degrees at once. After this, the temperature dropped by one degree per minute till it was on 51 degrees after ten minutes.

The insulation clearly helped for keeping the temperature. It is much harder for the thermal energy to leave the tube when it is trapped inside Styrofoam, since it is a bad conductor of it. The temperature started at 58 degrees (see last paragraph) and barely developed anything, staying on the very same degree for two or three minutes in a row. Ending on 54 degrees, it only changes four degrees, while for example the black tube change 20.

The copper tube’s temperature drop was quite steady, starting at 59 and after ten minutes being on 48 degrees. It varied a lot from dropping one and two degrees, once staying on the same temperature for two minutes. I would have expected a bigger jump for the first minute, otherwise it is as I expected.

It all appeared to be quite a lot as I expected it to, even though I thought that there would be larger temperature; what I expected was about five degrees per minute turned out to be a median of one or two. I hadn’t thought much of difference between the three (excepting the insulated one) and I was kind of right about this since this fourth tube clearly stood out from the rest. I have afterwards realised that the black colour much easier conduct thermal energy than the shiny and the copper.