Utility: Dihybrid Punnett Square Maker
A Punnett Square is a visual representation of Mendelian inheritance. It is a table consisting of possible combinations of the parent alleles, which can be used to determine the probability of an offspring having a particular genotype for a given trait.
A monohybrid cross involves the crossing of parent alleles for a single trait and the resulting Punnett square lists the possible genotypes of the offspring for the given single trait.
A dihybrid cross involves the crossing of parent alleles for two independent traits and the resulting Punnett square is a 4x4 grid, which lists all possible allele combinations for the offspring describing the given two traits.
Mendel's law of independent assortment states that the alleles for separate traits are passed independently of one another from parents to offspring. The biological selection of an allele for one trait is not influenced by (or influences) the selection of an allele for any other trait. A dihybrid cross reaffirms Mendel's law of independent assortment.
This utility creates a dihybrid Punnett square based on the allele symbols entered by you for each parent, for two different traits.
Utility: Dihybrid Punnett Square Dice - Random Parent-Child Alleles Generator
A Punnett Square is a visual representation of Mendelian inheritance. It is a table consisting of possible combinations of the parent alleles, which can be used to determine the probability of an offspring having a particular genotype for a given trait.
A dihybrid cross involves the crossing of parent alleles for two independent traits and the resulting Punnett square is a 4x4 grid, which lists all possible allele combinations for the offspring describing the given two traits.
Mendel's law of independent assortment states that alleles for separate traits are passed independently of one another from parents to offspring. The biological selection of an allele for one trait is not influenced by (or influences) the selection of an allele for any other trait. A dihybrid cross reaffirms Mendel's law of independent assortment.
This random generator utility, like a dice, keeps regenerating the Punnett square with a new set of parents having different alleles each time for the two independent traits. Out of the sixteen possible allele combinations for the child, one allele combination is selected randomly. This is a great utility for the classroom or for projects, where you need to create data for Mendelian inheritance.
DIY Newton's Second Law - Modified Atwood Machine 2 (with friction)
Newton's second law can be summed up as:
Σ Force = mass x acceleration
Accordingly, a net force acting on an object will cause it to accelerate in the direction of the net force.
This interactive features a modified Atwood machine having two masses (objects) connected by a string, which is moving over a pulley. Object A rests on a surface, while Object B hangs freely. Since the two objects are connected by a taut string, both experience the same acceleration arising due to the net force acting on each object.
To begin with, object A can move only if: |WaX| - |T| > FS
Where, T is the tension (force) in the string; WaX is the component of the weight of object A along the direction of the surface, when inclined; FS is the static friction (force) between object A and the surface on which it rests.
If object A is moving, there are two possibilities:
(1) If |T| > |WaX|, then summation of forces, with sign:
Σ Fa = T - WaX - FK = ma . a (object A moves right)
(2) If |T| < |WaX|, then summation of forces, with sign:
Σ Fa = T - WaX + FK = ma . a (object A moves left)
FK is the kinetic friction (force) between object A and the surface, always acting opposite to the direction of motion.
Net force (with sign) on object B in both cases is:
Σ Fb = Wb - T = mb . a
DIY Sonar - Mapping Underwater Depth 2 (with depth adjustment)
Sonar (SOund Navigation And Ranging) is a technique that uses propagation and reflection of sound waves to navigate or detect objects, usually under water.
An active sonar uses a transmitter to create a pulse of sound (called ping), which propagates through water and gets reflected (echo) when it hits an obstruction. The total time taken for transmission and reflection of the ping indicates the distance of the obstruction from the sonar transreceiver.
This interactive lets you specify heights of some cement columns constructed at the base of a shallow lake. A drone submarine fitted with a sonar device then moves below the lake surface and uses sound pulses (pings) to determine the depth of each cement column below the surface of the water.
The velocity of sound in water is approximately 1500 m/s. The duration of the ping echo is measured in milliseconds, where 1 second = 1000 milliseconds (ms).
For example, if the total travel time taken to transmit and receive a ping is 9.334 ms, the distance would be:
Distance = Velocity x Travel Time = 1500 x (9.334/1000) = 14 m
Since the ping travels to the object and is reflected back, it travels twice the distance, hence the actual distance up to the object is half the distance traveled by the ping.
Actual Distance = Ping Distance/2 = 14/2 = 7 m
DIY - Ideal gas law - Effect of moles of gas on its volume based on Avogadro's law
This interactive investigates the effect of the change in the amount (moles) of gas on the volume of gas in an enclosed container, with temperature and pressure remaining constant.
In this case, it is assumed that the relationship between volume, pressure, moles, and temperature of the gas is governed by the ideal gas law, PV = nRT.
The relationship between the amount (moles) and the volume of gas is described by Avogadro's law, which states that the volume and the amount of gas are directly proportional if the temperature and pressure are held constant.
The activity involves changing the amount (moles) of an ideal gas over time to observe the corresponding change in volume, for a given constant temperature and constant pressure. Compare the effect of a gradual increase in the moles of gas on its volume across two trials.
DIY PE-KE Energy Conversion 1 - Roller Coaster
Gravitational potential energy (GPE) is the energy stored in an object due to its position in a gravitational field.
GPE = m.g.h
The gravitational potential energy possessed by an object is determined by its mass (m), the gravitational acceleration (g) at the location and the height (h) of the object above a reference baseline (usually surface of the earth, but not necessarily), which is considered to be at height = 0.
Kinetic energy (KE) is the energy of an object due to its motion.
KE = ½ m.v2
The kinetic energy of an object is independent of the position and depends on the mass (m) and the rate of change of position of the object i.e. its velocity (v).
Energy can be converted from one form to another. For e.g, in the case of a ball falling from a height, its potential energy converts into kinetic energy as the ball continues to fall down (assuming effects of friction are negligible).
This interactive investigates the effect of mass and height on the potential energy of a roller coaster car and how it converts into kinetic energy as it glides down the track. The activity consists of two trials, where you can set the mass and height of a roller coaster for each trial and compare the conversion of potential energy to kinetic energy between the two trials.
DIY PE-KE Energy Conversion 2 - Roller Coaster on Different Planets
Gravitational potential energy (GPE) is the energy stored in an object due to its position in a gravitational field.
GPE = m.g.h
The gravitational potential energy possessed by an object is determined by its mass (m), the gravitational acceleration (g) at the location and the height (h) of the object above a reference baseline (usually surface of the earth, but not necessarily), which is considered to be at height = 0.
Kinetic energy (KE) is the energy of an object due to its motion.
KE = ½ m.v2
The kinetic energy of an object is independent of the position and depends on the mass (m) and the rate of change of position of the object i.e. its velocity (v).
Energy can be converted from one form to another. For e.g, in the case of a ball falling from a height, its potential energy converts into kinetic energy as the ball continues to fall down (assuming effects of friction are negligible).
This interactive investigates the effect of mass and height on the potential energy of a roller coaster car and how it converts into kinetic energy as it glides down the track. You can also conduct an imaginary experiment to investigate effect of gravitation acceleration (g) by transporting the roller coaster to either the Moon or the planet Mars. You can even go to a fictitious planet whose value of g can be set by you.
Homeostasis - Effect of Water Temperature on Goldfish Respiration Rate
Homeostasis is the ability of an organism to maintain a stable internal environment despite changes in the external environment. Some examples of homeostasis include the regulation of the organism's body temperature, the pH of its extracellular fluids, glucose concentration, etc.
The domestic goldfish (Carassius auratus), like most fishes, are poikilothermic, which means its body temperature changes with the ambient temperature of the water around it. One way by which a goldfish responds to the changes in the ambient temperature by regulating its rate of respiration (breathing).
This interactive investigates the effect of the temperature of the surrounding water on the respiration rate of a goldfish. The activity involves reducing the temperature of the water very gradually, in steps of 1°C at a time. The temperature is then held constant until the goldfish has regulated and stabilized its respiration rate in response to the new ambient temperature.
The goldfish's rate of respiration can be determined by either counting the number of times the fish opens and closes its mouth or by counting the number of times its gills contract during a given unit of time.