Name: suspensions, sedimentation, and colloids
Uploaded: 2023-06-23T15:38:43.000Z
Duration: 1 min 17 s
Channel: JoVE

الغرويات والمعلقات عبارة عن مخاليط غير متجانسة من مكونين أو أكثر مختلطة جسديا.
في الغروانية ، يتراوح حجم الجسيمات المذابة من 1 إلى 1000 نانومتر ، وهي صغيرة بما يكفي بحيث تكون غير مرئية بشكل فردي. ومع ذلك ، يمكن لهذه الجسيمات المذابة أن تشتت الضوء ، مما يجعل الغرويات تبدو شفافة أو معتمة. يبقون في الحل إلى أجل غير مسمى ولا يستقرون.
العصارة الخلوية ، المادة شبه السائلة داخل الخلايا الحية ، هي مادة غروية بسبب البروتينات والمستقلبات العديدة المنتشرة فيه.
في المقابل ، تحتوي المعلقات على جزيئات كبيرة ، عادة ما تزيد عن 10000 نانومتر ، وغالبا ما تكون مرئية بالعين المجردة.
عندما تترك دون إزعاج ، تستقر هذه الجسيمات على شكل رواسب.
الدم مثال على التعليق. عندما يترك الدم المسحوب حديثا دون إزعاج لبعض الوقت ، تستقر خلايا الدم الحمراء في قاع الحاوية. الجزء السائل العلوي ، المسمى بلازما الدم ، هو محلول من المواد المذابة الصغيرة بالإضافة إلى الغروانية التي تحتوي على بروتينات بلازما أكبر.

الغرويات والمعلقات

<div style="direction:rtl">غالبًا ما يصنع الأطفال أثناء اللعب معلقات مثل مخاليط الطين والماء، أو الدقيق والماء، أو معلق الأصباغ الصلبة في الماء المعروف باسم طلاء التمبرا. هذه المعلقات عبارة عن مخاليط غير متجانسة تتكون من جسيمات كبيرة نسبيًا يمكن رؤيتها بالعين المجردة أو رؤيتها بالعدسة المكبرة. وهي غائمة، وتستقر الجسيمات العالقة بعد الخلط. تستقر الجسيمات العالقة في المعلق بعد مرور بعض الوقت من الخلط. ويسمى فصل الجسيمات من المعلق بالترسيب. يقيس اختبار الدم لتحديد معدل الترسيب مدى سرعة ترسب خلايا الدم الحمراء في أنبوب الاختبار من الجزء المائي من الدم (المعروف باسم البلازما) خلال فترة زمنية محددة. لا يحدث الترسيب السريع لخلايا الدم عادةً في الجسم السليم. ومع ذلك، يمكن أن تتسبب بعض جوانب بعض الأمراض في تكتل خلايا الدم معاً، وتستقر هذه التكتلات الثقيلة من خلايا الدم في قاع أنبوب الاختبار بسرعة أكبر من خلايا الدم الطبيعية. تُظهر فئة أخرى من المخاليط تُسمى الغرويات (أو المشتتات الغروية) خواص متوسطة بين خواص المعلقات والمحاليل. فالجسيمات الموجودة في الغرويات أكبر من معظم الجزيئات البسيطة؛ لكن الجسيمات الغروية صغيرة بما يكفي بحيث لا تستقر عند الوقوف. تكون الجسيمات في الغروانية كبيرة بما يكفي لتشتت الضوء؛ وهي ظاهرة تسمى تأثير تيندال؛ ولهذا السبب تبدو المخاليط الغروية غائمة أو معتمة، مثل أشعة الكشاف. السحب هي أيضًا مخاليط غروانية. وهي تتكون من قطرات ماء أكبر بكثير من الجزيئات ولكنها صغيرة بما يكفي لعدم ترسبها. تتمتع بعض الغرويات بخاصية الخضوع لتحولات ذائبة - هلامية، والتي يمكن أن تتحول بشكل عكسي من حالة السائل إلى الحالة الصلبة (الهلام). على سبيل المثال، تتصلب منتجات الجيلاتين لتكوين مادة هلامية عند تبريدها، والتي يمكن أن تسيل مرة أخرى عند تسخينها. تُعد الخاصية الهلامية الهلامية للسائل الخلوي، وهو سائل الخلايا الحية، ضرورية للعديد من الأنشطة الخلوية، مثل انقسام الخلية أو تغير شكل الخلية. يُطلق على المكون الجسيمي للمحلول الغروي، الموجود بكمية قليلة نسبيًا، اسم الطور المشتت. ويُطلق على المادة أو المحلول الذي تتوزع فيه الجسيمات اسم وسط التشتت. هذا النص مقتبس م <a href="https://openstax.org/books/anatomy-and-physiology-2e/pages/2-4-inorganic-compounds-essential-to-human-functioning">Openstax, Anatomy and Physiology 2e, Section 2.4: Inorganic Compounds Essential to Human Functioning</a> and <a href="https://openstax.org/books/chemistry-2e/pages/11-5-colloids">Openstax, Chemistry 2e, Section 11.5: Colloids</a>.</div>

غالبا ما يقوم الأطفال أثناء اللعب بعمل معلقات مثل مخاليط الطين والماء والدقيق والماء ، أو تعليق الأصباغ الصلبة في الماء المعروفة باسم درجة الحرارة ...

Education

JoVE Core

Anatomy and Physiology

التشريح وعلم وظائف الأعضاء

Unit 1

الوحدة الأولى

Fundamentals of Chemistry

أساسيات الكيمياء

KEY TERMS AND CONCEPTS

المصطلحات والمفاهيم الأساسية

Colloids and Suspensions

suspensions, sedimentation, and colloids

Suspensions and colloids are two common kinds of mixtures seen in everyday life. Mud and water, flour and water, and tempera paint are suspensions. These mixtures are heterogeneous, which means their particles are not spread out evenly. The particles are relatively large and can be seen with the naked eye or a magnifying glass.

Suspension particles make mixtures cloudy, and they settle out after mixing. The settling of particles in a suspension is called sedimentation. A blood test can measure the rate of sedimentation by showing how fast red blood cells settle out of plasma, the watery part of blood, in a test tube over time. Rapid sedimentation is not usual in a healthy body, but some diseases can cause blood cells to clump together and sink faster than normal cells.

Colloids, also called colloidal dispersions, sit between suspensions and solutions. Their particles are larger than most simple molecules, but they are small enough that they do not settle out when left standing. Colloidal particles are still large enough to scatter light. This is known as the Tyndall effect, and it makes colloids look cloudy or opaque, like a beam from a searchlight.

Clouds are another example of a colloid. They contain water droplets that are bigger than molecules, but still small enough to stay suspended in the air. Some colloids can also change from a fluid sol to a solid gel and back again. Gelatin is one example. It forms a gel when chilled and can become liquid again when heated. The sol-gel behavior of cytosol, the fluid inside living cells, is important for cell division and for changes in cell shape.

In a colloid, the dispersed phase is the particulate part present in smaller amount. The dispersion medium is the substance that carries the particles throughout the mixture. These terms help describe how colloids are organized and why they behave differently from suspensions and solutions.

Suspensions, Sedimentation, and Colloids

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Chemical Symbols and Element Names

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Atomic Mass and Mole Calculations

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isotopes and radioisotopes

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Ionic Bonds and Charge Transfer

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Polar and Nonpolar Covalent Bonds

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hydrogen bonds

Hydrogen Bonding and DNA Stability

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Atomic Charges, Bonds, and Compounds

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states of matter

Solids, Liquids, Gases, and Plasma

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colloids and suspensions

Suspensions and colloids are two common kinds of mixtures seen in everyday life. Mud and water, flour and water, and tempera paint are suspensions. These mixtures are heterogeneous, which means their particles are not spread out evenly. The particles are relatively large and can be seen with the naked eye or a magnifying glass. Suspension particles make mixtures cloudy, and they settle out after mixing. The settling of particles in a suspension is called sedimentation. A blood test can measure...

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Electron Transfer and Chemical Equilibrium

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key terms and concepts

Learn how suspensions settle, how sedimentation works, and why colloids stay cloudy without settling. Explore real examples like blood, clouds, and gelatin.

Suspensions, Sedimentation, and Colloids | JoVE K12

anatomy and physiology

JoVE Core Anatomy and Physiology showcases the anatomical and physiological details of the human body in comprehensive, clear, and engaging video animations. This collection of lessons focuses on the structures, components, functions, and requirements of the human body. It is complemented by scientist-in-action videos that demonstrate the application of this knowledge in real-world medical and research settings.

Suspensions, Sedimentation, and Colloids

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