9 Facts About Bones

Shared by Anis Syazwany
Guest Blogger

The Little Engine in Us

Did you know that the heart of a blue whale is about 450 kilograms? That’s the weight of an average dairy cow!!

The heart is a bag-like structure in the chest region made completely of muscles. These muscles contract and relax from the time you were just a fetus in your mother’s uterus. 

The heart is made up of four chambers each with its own blood vessel. In these blood vessels are valves that make sure that blood flows in the right direction. The opening and closing of these valves are what gives the ‘lub-dub’ sound of your heartbeat. 

The heart pumps thousands of liters of blood through your body every day. First, it sends blood without any oxygen to the lungs to get oxygen. It then pumps the blood containing oxygen around all the other parts of the body. After delivering its oxygen, the blood returns to the heart to start the process of getting oxygen all over again.

During exercise, more oxygen and nutrients are needed by the muscles so blood must be delivered faster than when the body is resting. To meet these demands, the heartbeat increases. 

Generally, stethoscopes are used to listen to the heart, lungs, and intestinal tract but can also be used to listen to blood flow through vessels. The stethoscope is a very important tool used by medical professionals and health care workers to listen to your heartbeat.

If you want your heart to be healthy for the rest of your life, get plenty of exercise, follow a good diet and keep your heart clean and drug-free.

Experiment: Make your own stethoscope

Materials: 
60cm-long rubber hose, plastic funnel and masking tape.

Steps:
1.    Insert the nozzle of the plastic funnel into the opening of one end of the 60cm-long rubber hose. 

2.    Wrap the neck of the plastic funnel where it joins the rubber hose with masking tape to ensure it is airtight.
3.    Place the mouth of the plastic funnel on your chest and place the opening end of the rubber hose to your ear.
4.    Listen closely to your heartbeat.


Glossary of terms:

Muscle [muhs-uhl] tissues in the body that produce movement
Uterus [yoo-ter-uhs] the organ in a woman’s body where a fetus develops
Blood vessel [bluhd ves-uhl] tubes that circulate blood throughout the body
Valve [valv] a structure that allows fluid to flow in one direction only
Oxygen [ok-si-juhn] a colorless, odorless gas in the atmosphere that is used in respiration

Shared by Surain A. Victor

Guest Blogger

When Yummy Turns Smelly

Have you ever wondered why some people get a stomach upset after consuming milk? They will experience stomach cramps and give out a lot of gas before rushing to the toilet to relieve their bowels a few hours after drinking milk or consuming dairy products like ice cream. 

This condition is called lactose intolerance. It is not a disease; it’s just that they are not able to properly digest milk. Milk is a whole food that contains carbohydrates, proteins, lipids, vitamins, minerals and salts. As for early breast milk, it additionally contains antibodies. 

The carbohydrate found in milk is called lactose, a kind of sugar. Lactose is broken down by the enzyme lactase before it enters the bloodstream. Unfortunately, for those who are lactose intolerant, they do not have this enzyme in their digestive system. Therefore, the lactose will instead be fermented by bacteria found in the gut, and this process will produce acids that cause the stomach cramps, and lots of carbon dioxide, that causes the person to give out a lot of gas, also known as flatulence. Be prepared to take in the unpleasant odours when sitting next to a person who is lactose intolerant! 

All mammals, including humans, have the enzyme lactase in their digestive system when they are being breast-fed, also called the weaning period. As they develop the ability to consume other types of food, their lactase levels in their digestive system will drop. More than ninety percent of Asian and African adults are lactose intolerant, while only five percent of Caucasian adults have this condition.

So, when you reach teenage years or adulthood, you may need to cut down on the consumption of milk and dairy products if you find yourself getting bloated, stomach cramps, and giving out a lot of gas after drinking milk. 

Experiment: To emulsify the fat molecules in milk

Materials
A flat tray, food colouring (3 different colours), whole milk, and liquid soap.

Steps

1. Pour the milk into the tray so that it covers the bottom.

2. Add about 6 – 8 drops of different coloured food colouring onto the milk at different spots.

3. Add about 5 drops of liquid soap onto the drops of food colouring and observe what happens.

4. When you drop the liquid soap onto the milk, it tries to break down the fat in the milk. This process is called emulsification. While it was doing that, it caused the colour to scatter and mix creating a very colourful display.

Glossary

Lactose [lak-tohs] – a disaccharide found in milk that breaks down into glucose and galactose.

Intolerant [in-tol-er-uhnt] – unable to tolerate or endure.

Flatulent [flach-uh-luhnt] – generating gas in the alimentary canal.

Emulsify [ih-muhl-suh-fahy] – to make into or form an emulsion.

Shared by Surain A. Victor

Guest blogger

5 Classroom Memories From Us!

Teacher’s Day is on the 16th of May so let's watch videos below as we share some classroom memories from our staff and volunteers in recognition of the great work teachers do. 
Happy Teacher's Day!


Classroom Memories #1
Here’s classroom story by our volunteer, Firzanah. In her story, a ‘punishment’ by her teacher helped her understand physics so much better!

Classroom Memories #2

Petrosains staff Asma shares how her teacher helped her understand the states of matter through the point of view of molecules! Watch the video to listen to her story.

Classroom Memories #3

Use stories to remember the facts of biology! Shamini, our Director of Marketing, shares her valuable memory on the approach used by her biology teacher which helped her understand what was taught.

Classroom Memories #4

‘Pay attention in the classroom and fill in the blank’! These words from the teacher of our volunteer Yap Mei Ling was a useful way for her to learn. Watch the video to see how it helped!

Classroom Memories #5

Petrosains staff Nazri shares in this video his classroom memory on how his teacher explained the science behind combustion. How well do you understand combustion? Check the video out!

Thank you teacher!

Posted by Ayu
Petrosains

Why Are Mosquito Bites Itchy?

Posted by Ayu

Petrosains

Yang Mana Satu Cacing Jantan, Yang Mana Satu Cacing Betina?

Yang mana satu cacing jantan dan yang mana satu cacing betina? Bagaimana untuk membezakan jantina mereka? Cuba perhatikan pada keadaan fizikal cacing tanah seperti dalam dibawah. Bolehkah kita mengetahui yang mana satu memiliki organ pembiakan jantan dan yang mana satu memiliki organ pembiakan betina?

Sebenarnya, memang tiada perbezaan daripada segi fizikal pada cacing tanah yang boleh membezakan jantinanya. 

Cacing tanah adalah 'hermafrodit' iaitu memiliki kedua-dua organ pembiakan seks jantan dan betina pada setiap seekor cacing tanah. Walaubagaimanapun, seekor cacing tanah perlu mengawan dengan cacing tanah yang lain bagi menghasilkan telur supaya spesies ini akan terus membiak. 

Kokon cacing tanah yang seakan-akan menyerupai bentuk buah lemon
Imej kredit: U.S. Department of Agriculture

Gambar diatas adalah kokon cacing tanah. Telur-telur yang terhasil daripada  proses pembiakan akan berada di dalam kokon sebelum ia matang untuk menetas keluar. Pada kebiassannya, terdapat satu telur atau lebih dari satu telur dalam setiap kokon.

Cacing tanah mungkin menggelikan tetapi spesies ini memiliki banyak keunikkan semulajadinya yang tersendiri. Berikut adalah di antara pautan yang dicadangkan bacaan selanjutnya:
http://ecowatch.com/2014/03/08/10-facts-about-earthworms/
http://www.biologyjunction.com/earthworm%20facts.htm

Pelajari dengan lebih mendalam tentang cacing tanah dan mencuba untuk menyentuhnya di Petrosains bersempena Face Your Fears! sehingga 4 Januari 2015 ini! 

Maklumat lanjut boleh didapati di http://www.petrosains.com.my/page/public/thematic-programmes.php

Do Fish Urinate?

Yes they do!  But why?

Well, like most living things, fish too produce waste from their metabolic processes.   Peeing is one way of doing that and is referred to as excretion.  Elimination on the other hand refers to pooping, i.e. the removal of solid waste comprising undigested foods and digestive by-products.  How much they pee depends on the environment they live in and the adaptations it has undergone for survival.

Marine fish drink a lot while freshwater fish pee a lot. Why?

Freshwater Fish and Marine Fish

The difference between these two types of fish lies in the salinity of the fish’s environment and the inside of its body. Since the fish’s skin is so thin, especially around places like the gills, external water constantly tries to invade the fish’s body by osmosis and diffusion.

Image credit: Indiana University-Purdue University Indianapolis Earth Sciences

Maintaining the Balance

Osmosis takes place when two solutions are separated by a partially permeable membrane. A partially permeable membrane lets some particles through but not others. Cell membranes are partially permeable. Water can move freely through them but other particles, such as sugar molecules, cannot.

Osmoregulation is the process of maintaining an internal balance of salt and water in a fish’s body and is carried out with the help of the kidneys.  Do bear in mind that a fish is a collection of fluids floating in a fluid environment, with only a thin skin to separate the two.  

Role of the Kidneys

The kidneys are slightly different from mammals. They are smaller, stretched and do not resemble beans. Generally, within fish, the kidney is located towards the very middle of the fish both lengthwise and height wise.

Freshwater Fish
Body is more saline than the surrounding water and constantly gains water from the environment

• The kidney prevents excess solute loss as they contain more salts within their blood than the water located around their bodies. 

• Water will diffuse into the fish through osmosis causing large amounts of water to build up inside. 

• The kidney will then increase the amount of water that passes out in the urine and actively reabsorb the salts that would pass out to maintain balance. 

• This results in the production and excretion of large amounts of dilute urine - almost completely composed of water.

Marine Fish
Body is less saline than the surrounding water and constantly loses water to the environment.

• The function of the kidney here is almost opposite to that of the freshwater fish as the water and liquid around them is highly concentrated with salts and other solutes. 

• Water in the fish is constantly being 'sucked out' into the surrounding water through osmosis. This is because the fluids inside their bodies are less concentrated than the saltwater around their bodies. 

• The fish must counteract this process through drinking water and the use of their kidneys. 

• By constantly taking in water, the fish is constantly replacing water that is sucked out of it however, this can lead to an extreme intake of salts and buildup of harmful substances within the fish. 

• These salts are removed through the use of the kidneys whereby they help the fish retain water and actively excrete salts to produce a very concentrated urine. This also means that marine fish do not urinate as much as freshwater fish.

Shared by Azni

Learning Specialist, Petrosains

Ingin tahu tentang mata?

Dalam menjalani kehidupan seharian, banyak perkara yang kita perlu fahami supaya pengetahuan yang diperolehi dapat dimanfaat semasa ia diperlukan. Misalnya, dengan cara memahami bagaimana mata kita berfungsi, ia secara tidak langsung membantu kita mengetahui punca-punca dan membolehkan kita mencegah dari jangkitan penyakit yang berkaitan dengan mata. Kita juga mampu membuat keputusan yang tepat ketika hendak mendapatkan sebarang rawatan mata daripada pakar perubatan sekiranya berlaku jangkitan penyakit terhadap mata.

Secara definisi, mata merupakan satu organ yang telah terbentuk untuk mengesan cahaya. Secara ringkas, ia berfungsi untuk mengesan sama ada keadaan sekeliling terang atau gelap. Pada kebiasaannya, semua benda hidup mempunyai sepasang mata. Ia berbentuk hampir sfera, berisi bahan seperti gel optik jernih yang dikenali sebagai gelemaca, dengan kanta fokus dan otot yang dikenali sebagai iris mata yang mengawal kadar cahaya yang masuk. Iris mata ini mengawal bukaan anak mata atau dikenali juga sebagai pupil, iaitu bulatan hitam di tengah-tengah bahagian berwarna di dalam mata.

Di Petrosains, kita dapat mempelajari mengenai struktur mata secara terperinci melalui aktiviti ‘pembedahan mata lembu’. Tujuan aktiviti ini adalah untuk melihat dan mengenal pasti bahagian –bahagian dalam mata seperti kornea, kanta, iris dan retina serta fungsinya. Mata lembu dipilih dan digunakan kerana struktur mata lembu adalah hampir sama dengan mata manusia.

Pada kebiasaannya, mata bertindak dengan memancarkan imej ke atas retina yang sensitif kepada cahaya. Kornea dan kanta akan menumpukan cahaya yang masuk ke atas retina, yang mengaktifkan suatu tindak balas kimia dan menghasilkan isyarat yang untuk dihantar ke otak melalui saraf optik.

Cahaya yang masuk dari luar akan melepasi kornea dan melalui gelemair sebelum sampai ke kanta. Gelemair membantu mengekalkan bentuk cembung kornea dan melembapkannya. Seterusnya cahaya itu akan melalui gelemaca sebelum sampai di retina. Di sinilah terletak banyak sel-sel yang sensitif kepada cahaya.

Pastinya mata merupakan anugerah yang sangat berharga kepada semua benda hidup. Jadi, kita perlu menjaga dan memelihara kesihatan mata. Salah satunya adalah dengan mengamalkan pemakanan sihat seperti pengambilan ubi keledek, lobak merah dan sayur-sayuran hijau yang kaya dengan sumber vitamin A dimana ia dikatakan adalah baik untuk mata kita. Elakkan juga dari menyentuh mata dalam keadaan tangan yang kotor kerana ia dapat menginfeksi mata kita dan akan mengakibatkan mata terdedah kepada pelbagai penyakit mata.

Untuk mencuba melakukan pembedahan mata lembu, sertai aktiviti 'Cow Eye Dissection' di Petrosains sempena Petrosains Science Festival 2014 dari 15-21 September 2014. Maklumat lanjut boleh didapati di www.sciencefestival.my 

#petrosainsfest 

Posted by Ayu
Learning Specialist, Petrosains

Are spiders and tarantulas insects?

Mexican Red-kneed Tarantula
Image credit: George Chernilevsky

No!  They are arachnids.  Scorpions, mites and ticks are considered as family members. Many people think spiders are insects but they are mistaken as insects have six legs and three main body parts.  Scientists suggest there are over 75,000 species of arachnids, the majority of them spiders.

Wolf Spider
Image credit: Philip N. Cohen

What are arachnids anyway?  They are creatures with two body segments, eight legs, no wings or antennae and are not able to chew.  Many arachnids use silk, either to catch prey or to help them reproduce.  Most can only eat liquid food, so they squirt digestive chemicals into their prey and suck out the juice.  They are predators on insects and other invertebrates, except for many mites which feed on all kinds of things, like fungus, plants, dead animals, bacteria and other invertebrates.

Dew covered spider web
Image credit: Rosendahl

Tarantulas are a type of spider but are somewhat different from most spiders.  So, what’s the difference between them?

• Tarantulas are usually larger than most spiders.

• Not all spiders are hairy-bodied, whereas tarantulas are always.

• Tarantulas have two or four spinnerets (silk exuding tube-like structures) while spiders have six.

• Spiders exude silk to make webs to capture prey, whereas tarantulas do that for carpeting of floor of the nest and make hammock-like bedding for resting.

• Silk producing glands in the feet are unique for the tarantulas.

• Presence of barbs on the fleshy abdomen is a distinguishing feature of tarantulas.

• The lifespan for tarantulas is very high compared to spiders.

Why don’t you catch a spider and examine how it looks like?  Make sure you handle it with care and return it to where you got it from.  Forget about tarantulas.. they are DANGEROUS!

Sign up for the 'Spiders & Tarantula' interactive sessions happening during Petrosains Science Festival from 15-21 September 2014. Get your tickets at www.sciencefestival.my NOW! #petrosainsfest

Shared by Azni

Learning Specialist, Petrosains

Fast Growing Plants

We use catalysts to get faster chemical reactions, growth hormones to stimulate growth & cell reproduction and regeneration in humans or animals, and sometimes fertilisers are added to soil to improve its fertility.

How do we get plants to mature in the shortest possible time?

Pineapples for instance take about 2 years to grow before it could be eaten.  What if we could reduce its growth by a few months?  Can it be done?

Yes we can, and the answer is by tissue culture.  Nothing magical or sinister, it’s just science!

So, what is tissue culture anyway?

Basically it’s just growing tissue (or cells) outside an organism, i.e. in a laboratory container under controlled environment conditions.  Single cells, plant cells without cell walls, pieces of leaves, stems or roots are exposed to specific nutrients, hormones and light under sterile conditions to produce several new plants - each a clone of the original mother plant, over a very short period of time.

How is micropropagation carried out?

The offspring all come from a single plant and have identical genetic make-ups to each other and to the mother plant. They are called clones.

What are the advantages of micropropagation over the conventional method of growing plants?

1. It is fast and produces thousands of plantlets within months. 

2. Healthy plant material is ensured since soil and disease-causing organisms are excluded during the propagation cycle. 

3. The method is programmable as it is independent of seasonal changes and the weather. 

4. It saves an enormous amount of care usually required by cuttings and seedlings (watering, weeding, spraying etc.) 

5. Excess material produced can often be stored over long periods. 

6. Species and cultivars can be stored in small spaces.

Tissue culture is not really new technology as it owes its origin to the ideas of the German scientist, Haberlandt, at the beginning of the 20th century. It has now come to a stage that it is imperative we use more of this technology due to pressing environmental concerns. Changing climate, fast expanding world population and scarcity of food in many parts of the world are major concerns and many scientists believe this is one of the many ways to deal with it.  

So folks, we don’t have to wait too long to enjoy our favourite fruits.  It’s NOT MAGIC but it’s worth the short wait!

This article is written in conjunction with the Science Engagement Session at HotScience, Petrosains from 3-4 May 2014 with Nuclear Malaysia led by Dr. Rusli Ibrahim, Puan Norazlina Noordin & their team.

Shared by Azni
Learning Specialist, Petrosains