Thursday, October 22

The 200mm test tube also contained some water

Microbes that rank among the simplest and most ancient organisms on Earth could survive the extremely thin air of Mars, a new study finds. The martian surface is presently cold and dry, but there is plenty of evidence suggesting that rivers, lakes and seas covered the Red Planet billions of years ago.

Since there is life virtually wherever there is liquid water on Earth, scientists have suggested that life might have evolved on Mars when it was wet, and life could be there even now.

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Previous research detected methane, the simplest organic molecule, in the martian atmosphere. The same could possibly be true for Mars. Of course, there are a lot of possible alternatives to the methane on Mars and it is still considered controversial. But that just adds to the excitement. On Earth, microbes known as methanogens produce methane, also known as natural gas.

Methanogens typically live in swamps and marshes, but can also be found in the guts of cattle, termites and other herbivores, as well as in dead and decaying organic matter.

Methanogens are among the simplest and most ancient organisms on Earth. These microorganisms are anaerobes, meaning they do not require oxygen. Instead, they often rely on hydrogen for energy, and carbon dioxide is the main source of carbon atoms they use in creating organic molecules.

The fact that methanogens neither require oxygen nor photosynthesis means they could live just beneath the martian surface, shielded from harsh levels of ultraviolet radiation on the Red Planet. This could make them ideal candidates for life on Mars. However, the area just below the surface of Mars is exposed to extremely low atmospheric pressures, normally considered inhospitable to life. The surface pressure on Mars on average ranges from one-hundredth to one-thousandth that of the surface pressure of Earth over the course of the martian year, too low for liquid water to last on the surface.

In such thin air, water easily boils. To see if methanogens might survive such extremely thin air, Mickol and Timothy Kral, the senior author of the study and an astrobiologist at the University of Arkansas at Fayetteville, experimented with four species of methanogens.

They included: Methanothermobacter wolfeiiMethanosarcina barkeriMethanobacterium formicicumand Methanococcus maripaludis. Previous experiments on these four species over the course of more than 20 years generated a lot of data on these organisms and their rates of survival in simulated martian conditions.

The more recent set of experiments, which took about a year, involved growing the microbes in test tubes within liquids as a proxy for the fluids potentially flowing through underground martian aquifers. The microbes were fed hydrogen gas, and the liquids were covered with cotton swabs, which in turn were covered with dirt simulating what might be found on the martian surface. The insides of each test tube were then subjected to low pressures.

Moreover, water evaporates quickly at low pressure, which can limit how long the experiments can last and can also clog the vacuum system with water. The scientists are also measuring methane to see whether methanogens are actively growing at low pressure and producing methane. Mickol stressed that these experiments do not prove life exists on other planets.Experiments are interesting and they are more fun when you use real laboratory equipment like test tubes. You can use either plastic or glass test tubes, but the plastic ones are generally safer.

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Before you attempt any experiments, check with a parent or other adult. You need a test tube, iron nail, sandpaper, vinegar, ruler and a test tube rack. Add two inches of vinegar to the test tube.

How to Find the Volume in a Test Tube

Place the tube in the test tube rack. Alternatively, use a mound of modeling clay with a hole in the middle to accommodate the test tube. Sand the pointed end of the nail to obtain a clean surface. Put the nail, pointed side down, in the test tube and allow it to sit for several minutes. The bubbles you will see forming near the nail are hydrogen bubbles. Prepare the following solutions, one per glass with its own eye dropper: mL water mixed with red food coloring; 15 mL water with 5 mL ethyl alcohol and yellow dye; 10 mL water with 10 mL ethyl alcohol and green dye; 5 mL water with 15 mL ethyl alcohol and blue dye; and 20 mL ethyl alcohol, either clear or dyed purple.

Drop five drops of a solution into a 10 mm. Add five drops of another solution, letting the drops run down the inside of the tube. Find the order of density of all five solutions. If an upper layer is denser than the layer beneath it, it will mix with the lower layer or have an indistinct border. Rinse the test tube and start again. Chop some red cabbage into small pieces, put it into a microwave-safe bowl, cover the cabbage with water and microwave it until the water boils and is dark purple.

Let the container cool. Pour the purple water through a strainer into another bowl. Discard the cabbage. The test whether a substance, such as orange juice, milk or laundry detergent, is an acid or base, pour an inch of indicator into a test tube and add three drops of the test substance.

Acids turn the indicator pink. Put one teaspoon baking soda into a medium-size balloon using a funnel. Put 2 ounces of vinegar into the test tube. Stretch the neck of the balloon over the test tube opening, leaving the remainder of the balloon flopped over the side so the baking soda stays inside. When the two substances mix, they produce oxygen and the balloon inflates.

Annette Strauch has been a writer for more than 30 years. She has been a radio news journalist and announcer, movie reviewer for Family Movie Reviews Online, chiropractic assistant and medical writer. About the Author.Test tubes, also known as sample or culture tubes, are cylindrical tubes that typically have rounded, u-shaped bottoms, used to hold, mix, culture, or heat substances.

the 200mm test tube also contained some water

Test tubes are commonly used by chemists, biologists, researchers, and educators in education, medicine, and forensics. Test tubes support a variety of solid, semi-solid, liquid, or gas substances, including chemical or sample storage, and live organisms such as bacteria, plant cuttings, and blood. Test tubes come in a wide variety of materials. Glass test tubes, such as borosilicate, are selected for durability, and chemical and temperature resistance.

Glass test tubes can also be made of soda-lime glass material. Although most test tubes are made of glass, plastic test tubes are used in biological applications, and come in a variety of plastic test tube types such as polystyrene PS and polypropylene PP.

Plastic test tubes with caps or plugs are also used in lab practices. Test tubes are also commonly used with a stopper in biological or chemical samples.

Test Tubes

They commonly have uniform wall thickness for chemical resistance and maximum heat transfer. Some test tubes come with a marking spot for labeling, or a sturdy lip or bead top for durability. They typically either come with milliliter mL graduations, or unmarked. When selecting where to buy test tubes, purchasers should source from suppliers who offer varying lengths, capacities, and brands.

Test tubes can be manufactured to meet specific health standards. When distributors offer test tubes for sale, customers should evaluate with these features in mind for maximized product selection.

Skip to main content. FREE Shipping on eligible orders. Some sizes are Prime eligible. Only 9 left in stock - order soon. Previous Page 1 2 About Test Tubes Test tubes, also known as sample or culture tubes, are cylindrical tubes that typically have rounded, u-shaped bottoms, used to hold, mix, culture, or heat substances. Up to 0. Free Shipping by Amazon. Karter Scientific.

the 200mm test tube also contained some water

Hach Company. Frustration-Free Packaging. Lake Charles Manufacturing Amazon. Include Out of Stock. There's a problem loading this menu right now. Learn more about Amazon Prime. Get free delivery with Amazon Prime.In our bio class, we did a lab where we put pieces of potato of the same size in different test tubes.

Each test tube contained salt water with the salt concentration being different in each one. If a piece of potato is placed in a high salt concentration THEN the potato will become dehydrated BECAUSE water will move out of the potato cells, by osmosis, from a low to high concentration of salt.

The solution where salt is more is called hypertonic. We put the potato in water to see what would happen. The water from the potato goes into the test tube as a result the potato shrinks in size. The solution where salt is LESS than the salt in the potato is called hypotonic.

The water from the test tube goes into the potato as a result the potato increases in size. The solution where salt in test tube is the SAME as the salt in the potato is called isotonic. The water from the potato does not go into the test tube or the water in the test tube doesn't go into the as a result the potato does not shrink or become larger in size. The water internet course has to handle the concentration of the solute on the two sides of the membrane.

Then, communicate approximately hypertonic, hypotonic, and isotonic ideas Could someone help me with a purpose and hypothesis? Update: Also, my teacher wants an If. Because hypothesis. Answer Save. Favorite Answer. Still have questions? Get your answers by asking now.If you've ever wondered where to buy test tubes, you've found your answer! Find them in glass and plastic. HST's glass test tubes are made from strong borosilicate glass and can be heated, and our plastic ones are polystyrene.

Also find other complementary equipment for your laboratory experiments and science projects. Shop wooden or plastic racks standsculture tubes, metal clamps, cleaning brushes, and more. A lab test tube is ideal for working with small quantities of a liquid.

For example, in testing how much vitamin C is in lemon juice or other lab applications. Need rubber stoppers to fill the ends? HST is your source for all your lab supply needs. Click on a product to see available discounts for ordering 10 or more tubes or stands.

Our products are durable, reliable, and affordable to take you from the field to the lab to the kitchen. They won't let you down, no matter what they're up against. Whether it's over eager young scientists year after year, or rigorous requirements that come once-in-a lifetime. And if your science inquiry doesn't go as expected, you can expect our customer service team to help. Count on friendly voices at the other end of the phone and expert advice in your inbox. They're not happy until you are.

Bottom line? We guarantee our products and service won't mess up your science study—no matter how messy it gets. Shop By Age. Learn More. Our Guarantee. We get it. Science can be messy. But Home Science Tools' products and service can handle it. Get in touch with our Customer Service team. Which best describes you?In the field of phlebotomy, a variety of tubes are used to draw blood specimen for certain testing procedures. While the number of colors seem overwhelming to ordinary folks, health care professionals are trained to perform blood collection and differentiate one test tube from another as required by the specimen to be drawn.

Vacutainer tubes, as they are collectively called, were developed by Joseph Kleiner in and are currently being produced by Becton, Dickinson and Company, a global provider of medical supplies to the healthcare and pharmaceutical industry.

Different phlebotomy tubes are identified by the color of the stopper or shield. Specific colors indicate a presence of certain additives. They are categorized as tubes for coagulant blood tests, anticoagulant blood tests and other types of tests.

Tubes under this category are often used in patients with a bleeding disorder or are using a blood thinner medication. Tests are performed to check their ability to clot properly. Instead, it contains an additive that binds to calcium ions, inhibiting the proteins that lead to coagulation of blood specimens. Some of the tubes used are those with light blue, green, gray, dark blue and lavender or pink stoppers.

Other tests that are not classified as anticoagulant or coagulant use different tubes that contain specific additives or no additive at all. A tube with a red stopper does not contain additives and is used for testing for antibodies and drugs. There are also tubes with light yellow, tan and white stoppers. The same tubes are used for HLA phenotyping and for conducting parental tests.

Blood culture tubes and vials also come in stoppers other than yellow. Vials with blue, purple and pink top contain enriched soybean-casin broth with CO2. Aside from bacterial, they are used in fungal blood cultures. As an anticoagulant, citrate binds the calcium in blood that is needed for clotting.

Since the additive still results in a whole blood sample — plasma and red blood cells, the coagulation tubes also contain buffered tri-sodium citrate solution. Tubes with red-colored stoppers are used for serology and immunohematology. Plastic tubes need to be inverted to mix the blood with the coagulant. It usually takes 30 minutes for clotting to occur. Serology is done to check infectious mononucleosis, rheumatoid arthritis, syphilis, rubella titer, strep testing, pregnancy test, cold agglutinins, haptoglobin and C-reactive protein.

Some of the requested components include packed red blood cells, platelets, cryoprecipitate and fresh frozen plasma. Phlebotomy tubes with green top contain sodium herapin, lithium herapin and ammonium herapin, all of which are coated in the inside of the tube.

the 200mm test tube also contained some water

The herapin anticoagulant activates antithrombins that block the coagulation cascade and produce a plasma sample or whole blood. The same tubes are used for clinical chemistry and STAT chemistry tests. They contain a gel that separates plasma from the cells when centrifuged, and are used for a wide range of testing. Serum separator tubes make an acceptable substitute for PST. Tubes with purple or lavender-colored stoppers contain EDTA ethylenediaminetetraacetic acid additive that binds calcium ions, effectively blocking coagulation cascade.

Clinical laboratories use these to test for whole blood.Finding the volume of a test tube or NMR tube is a common chemistry calculation, both in the lab for practical reasons and in the classroom to learn how to convert units and report significant figures.

Here are three ways to find the volume. A typical test tube has a rounded bottom, but NMR tubes and certain other test tubes have a flat bottom, so the volume contained in them is a cylinder.

You can get a reasonably accurate measure of volume by measuring the internal diameter of the tube and the height of the liquid. Use the formula for the volume of a cylinder to perform the calculation:. The diameter which you measured is twice the radius or radius is one-half diameterso the equation may be rewritten:. Let's say you measure an NMR tube and find the diameter to be Calculate the volume. Report your answer to the nearest 0.

First, you'll want to convert the units so they're the same. Please use cm as your units, because a cubic centimeter is a milliliter! This will save you trouble when it comes time to report your volume. But, this is unrealistic precisiongiven your measurements. If you report the value to the nearest 0.

If you know the composition of the contents of the test tube, you can look up its density to find the volume. Remember, density equal mass per unit volume. Now, use the density of the sample to find its volume. Make sure the units of density are the same as those of the mass and volume you want to report.

You may need to convert units. Expect error in this calculation from your mass measurements and from any difference between the reported density and the actual density. This usually happens if your sample isn't pure or the temperature is different from the one used for the density measurement. Notice a normal test tube has a rounded bottom.

the 200mm test tube also contained some water

Also, it's tricky trying to measure the internal diameter of the tube. The best way to find the volume of the test tube is to transfer the liquid to a clean graduated cylinder to take a reading. Note there will be some error in this measurement, too. A small volume of liquid may be left behind in the test tube during transfer to the graduated cylinder.


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