Problem: I read this background article the other day: A thermometer is a device used to measure temperature. It is placed in contact with an object and allowed to reach thermal equilibrium with the object (they will have the same temperature). The operation of a thermometer is based on some property, such as volume, that varies with temperature. The most common thermometers contain liquid mercury, or some other liquid, inside a sealed glass tube. The liquid expands and contracts faster than the glass tube. Therefore, when the temperature of the thermometer increases, the liquid volume expands faster than the glass volume, allowing the liquid to rise in the tube. The positions of the liquid in the tube can then be calibrated for accurate temperature readings. Other properties that change with temperature can also be used to make thermometers; liquid crystal colors and electrical conductivity change with temperature, and are also relatively common thermometers. I am facing a new situation today: A group of middle school students is measuring the temperature of various liquids for a chemistry lab using a mercury thermometer. They have a beaker of boiling water, a beaker of ice water, and a beaker of water at room temperature. Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: If the students move the thermometer from the room temperature water into the ice water will the mercury level go up or down?

A: down

Problem: I read this background article the other day: Water stratification is when water masses with different properties - salinity (halocline), oxygenation (chemocline), density (pycnocline), temperature (thermocline) - form layers that act as barriers to water mixing which could lead to anoxia or euxinia.[1] These layers are normally arranged according to density, with the least dense water masses sitting above the more dense layers. Water stratification also creates barriers to nutrient mixing between layers. This can affect the primary production in an area by limiting photosynthetic processes. When nutrients from the benthos cannot travel up into the photic zone, phytoplankton may be limited by nutrient availability. Lower primary production also leads to lower net productivity in waters.[2] I am facing a new situation today: High lake had a lot of fresh and salt water mixing, therefore presented layers of stratified water.The water was poor in nutrients.Low lake had no such problems and it was a very abundant and prolific fishing spot. Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: Which lake had less dense layers of water?

A: Low lake

Problem: I read this background article the other day: In slippery conditions some riders prefer to ride fixed because they believe the transmission provides increased feedback on back tire grip. However, there is also an increased risk of loss of control in such conditions. This is especially so when taking into account the large number of riders who ride brakeless. These riders must brake entirely through the drivetrain. Ideally this is done by resisting the forward motion of the pedals, shedding speed while the bike is still moving. Alternatively, though far less efficiently, one can brake by stopping the motion of the pedals in mid-rotation, causing the rear wheel to lock in place, allowing the bicycle to skid and slow down from kinetic friction (see below).[22] Descending any significant gradient is more difficult as the rider must spin the cranks at high speed (sometimes at 170 rpm or more), or use the brakes to slow down. Some consider that the enforced fast spin when descending increases suppleness or flexibility, which is said to improve pedalling performance on any type of bicycle; however the performance boost is negligible compared to the benefits of riding a free wheel.[23] I am facing a new situation today: Two villages are inhabited by lots of people that ride bicycles. Hill village is located on a mountain and gets lots of rain, and Low village is situated in a valley, and has more sunny days. Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: Which village has more cyclists going uphill?

A: Hill

Problem: I read this background article the other day: Freezing is a common method of food preservation that slows both food decay and the growth of micro-organisms. Besides the effect of lower temperatures on reaction rates, freezing makes water less available for bacterial growth. I am facing a new situation today: Robert, a baker, has just baked a large batch of cupcakes for his store. He won't be able to sell all of his cupcakes within the next week, so he has decided to store a portion of them in the freezer to preserve them for later. He is trying to decide if he should store the cupcakes at 0 F or at 10 F in the freezer. Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: Which temperature will result in slower decay of the cupcakes?

A:
0 F