Friday, March 20, 2020

Using the Spanish Verb Sentir

Using the Spanish Verb Sentir Sentir is a very common verb that typically means to feel. It usually refers to feeling emotions, but it can also refer to physical sensations. The Difference Between Sentir and Sentirse Sentir commonly appears in the reflexive form sentirse. The difference in using sentir and sentirse is that sentir is typically followed by a noun, while sentirse is followed by an adjective or adverb describing how a person feels. Otherwise their meanings are essentially the same. Here are some examples of sentir used to describe emotional feelings: El atleta dijo que sentà ­a alegrà ­a y satisfaccià ³n por el logro del campeonato. (The athlete said he felt joyful and satisfied about attaining the championship.)Siento pena y tristeza por ello. (I feel shameful and sad about it.)Se siente feliz por ser abuela. (She feels happy about being a grandmother.)Me siento enojada y frustrada. (I feel angry and frustrated.) Here are examples of sentir being used with physical sensations. Although in most of these cases you could probably translate sentir as to sense, usually it would be better to translate based on the context: Puedo sentir pasos en la azotea. (I can hear footsteps on the roof.)Él me dijo que sentà ­a olor a muerte. (He told me he smelled death.) When sentirse de refers to a body part, it usually indicates the sensation of pain: Me siento de la cabeza. (I have a headache.) Standing by itself, sentir can indicate sorrow or regret: Lo siento mucho. Im very sorry. Using Sentir in Phrases It is common to use sentir as part of a phrase. Although you may not use feel in the most natural translation, often you can determine the meaning of the phrase from the individual words. Some examples: sentir algo por una persona (to have love or similar feelings for someone): Decirte que ya no siento algo por ti serà ­a mentir. (To say I no longer have feelings for you would be lying.) sentir celos (to be jealous): Cree que sà ³lo sienten celos las personas inseguras. (She believes that only insecure people have jealousy.) sentir culpa, sentirse culpable (to feel guilty): No sentà ­a culpa por lo que acababa de hacer. (He did not feel guilty for what he had just done.) sentir ganas de infinitivo (to feel like doing something): Siento ganas de llorar cuando pienso en el accidente. (I feel like crying when I think about the accident.) sentir que (to be sorry or sad that): Siento que mi color de piel ha cambiado. (I am sad the color of my hair has changed.) hacer sentir (to cause a feeling in someone): A veces nos hacemos adictos a alguien que nos hace sentir bien. (Sometimes we become addicted to someone who makes us feel good.) sin sentir (without being noticed): Tomà © la medicina sin sentir ninguna diferencia en mi vida. (I took the medicine without noticing any difference in my life.) This phrase is sometimes best translated literally:  ¿Cà ³mo es posible que te lo diga sin sentir? (How is it possible that she told you that without any feeling?) Using Sentir as a Noun Sentir also can be used as a noun to refer to feelings or sentiments: El sentir y el pensar son dos funciones de la mente. (Feeling and thinking are two functions of the mind.)El presidente representa el sentir del pueblo. (The president represents the feelings of the people.)Tenà ­a una vida dedicada a la promocià ³n del sentir indà ­gena. (He had a life dedicated to the promotion of indigenous sentiment.)Las almas no nos permitieron matar sin sentir. (Our souls did not allow us to kill unfeelingly.)Entiende muy bien el sentir de la calle. (He understands very well the feelings on the street.) Conjugation of Sentir Keep in mind that sentir  is irregularly conjugated. When it is stressed, the sent- of the stem changes to sient-, as in siento, I feel. And in some but not all forms, the stem changes to sint-, as in sintià ³, he or she felt. Unfortunately, this second stem change doesnt occur in a predictable way. The conjugation pattern is shared by about three dozen other verbs. Among them are consentir (to allow), convertir (to change), mentir (to lie), and preferir (to prefer). Also, the conjugated forms of sentir overlap with those of sentar, which means to sit. For example, siento can mean either I feel or I sit. This overlap is seldom a problem because the two verbs are used in such different contexts. Key Takeaways Sentir is a common Spanish verb that typically means to feel, especially in an emotional or mental sense.There is usually little difference in meaning between sentir and its reflexive form, sentirse.Sentir is conjugated irregularly in that its stem sometimes changes to sient- or sint-.

Wednesday, March 4, 2020

Heavy Water Facts

Heavy Water Facts Heavy water is deuterium monoxide or water in which one or more of the hydrogen atoms is a deuterium atom. Deuterium monoxide has the symbol D2O or 2H2O. It is sometimes referred to simply as deuterium oxide. Here are facts about heavy water, including its chemical and physical properties. Heavy Water Facts and Properties CAS number 7789-20-0 molecular formula 2H2O molar mass 20.0276 g/mol exact mass 20.023118178 g/mol appearance pale blue transparent liquid odor odorless density 1.107 gm/cm3 melting point 3.8C boiling point 101.4C molecular weight 20.0276 g/mol vapor pressure 16.4 mm Hg refractive index 1.328 viscosity at 25C 0.001095 Pa s specific heat of fusion 0.3096 kj/g Heavy Water Uses Heavy water is used as a neutron moderator in some nuclear reactors.Deuterium oxide is used in nuclear magnetic resonance (NMR) spectroscopy in aqueous solutions involving the study of a hydrogen nuclide.Deuterium oxide is used in organic chemistry to label hydrogen or to follow reactions involving water.Heavy water is often used instead of regular water in Fourier Transform Infrared Spectroscopy (FTIR) of proteins.Heavy water-moderated reactors are used to produce another isotope of hydrogen - tritium.Heavy water, made using deuterium and oxygen-18, is to test human and animal metabolic rates via the doubly labeled water test.Heavy water has been used in a neutrino detector. Radioactive Heavy Water? Many people assume heavy water is radioactive because it uses a heavier isotope of hydrogen, is used to moderate nuclear reactions, and is used in reactors to form tritium (which is radioactive). Pure heavy water is not radioactive. Commercial grade heavy water, much like ordinary tap water and any other natural water, is slightly radioactive because it contains trace amounts of tritiated water. This does not present any sort of radiation risk. Heavy water used as a nuclear power plant coolant contains significantly more tritium because neutron bombardment of the deuterium in heavy water sometimes forms tritium. Is Heavy Water Dangerous To Drink? Although heavy water isnt radioactive, its still not a great idea to drink a large volume of it because the deuterium from the water doesnt act quite the same way as protium (a normal hydrogen isotope) in biochemical reactions. You would not suffer harm from taking a sip of heavy water or drinking a glass of it, but if you only drank heavy water, youd replace enough protium with deuterium to suffer negative health effects. Its estimated you would need to replace 25-50% of the regular water in your body with heavy water to be harmed. In mammals, 25% replacement causes sterility. 50% replacement would kill you. Keep in mind, much of the water in your body comes from the food you eat, not just water you drink. Also, your body naturally contains small amounts of heavy water and every smaller amount of tritiated water. Primary Reference: Wolfram Alpha knowledgebase, 2011.