Utility: Monohybrid 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 monohybrid cross involves crossing of the parent alleles for a single trait and the resulting Punnett square lists the possible genotypes of the offspring for the given single trait.
This random generator utility, like a dice, keeps regenerating the Punnett square with a new set of parents having different alleles each time. Out of the four possible allele combinations for the child, one set of alleles 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 1 (no 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 force.
This interactive features a modified Atwood machine having two masses (objects) connected to each other by a string, which is moving over a pulley. One of the masses (object A) rests on a surface, while the other one (object B) hangs freely. The string and the pulley are assumed to be massless and frictionless. The surface over which object A is moving is also considered to be frictionless.
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.
Σ Fa = WaX + T = ma . a
Σ Fb = Wb + T = mb . a
Where, T is the tension in the string, and WaX is the component of the weight of object A along the direction of the surface, when inclined. If WaX>T, object A will accelerate towards left. If T>WaX, object A will accelerate towards right.
DIY Sonar - Mapping Underwater Depth 1
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.
This interactive lets you specify heights of some cement columns constructed at the base of a shallow lake. A drone ship fitted with a sonar device then moves through the lake and uses sound pulses (pings) to determine the depth of each cement column below the surface of 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 Simple Electric Circuit Building Challenge 1 - Series Circuit
This interactive consists of five challenges, which require you to build a simple electric series circuit according to the given requirements. Each challenge involves two steps:
Step 1
Build the circuit by connecting the devices mentioned in the question. Once the circuit is complete, click the DONE button. If the circuit is correct, proceed to step 2, else click TRY AGAIN and modify the circuit.
Step 2
If the circuit includes one or more switches, click on each switch and observe how the circuit works.
DIY Simple Electric Circuit Building Challenge 2 - Parallel Circuit
This interactive consists of five challenges, which require you to build a simple electric parallel circuit according to the given requirements. Each challenge involves two steps:
Step 1
Build the circuit by connecting the devices mentioned in the question. Once the circuit is complete, click the DONE button. If the circuit is correct, proceed to step 2, else click TRY AGAIN and modify the circuit.
Step 2
If the circuit includes one or more switches, click on each switch and observe how the circuit works.
Utility: Monohybrid 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 crossing of the parent alleles for a single trait and the resulting Punnett square lists the possible genotypes of the offspring for the given single trait.
This utility creates a monohybrid Punnett square based on the allele symbols entered by you for each parent.
Effect of drag coefficient on objects falling in air - 1
Terminal Velocity - An object falling through atmosphere (air) is subjected to two external forces. One is the weight of the object (gravitational force). The other force is air resistance, also known as drag. For a falling object, its weight acts in the direction of the fall, whereas drag acts in the opposite direction. Hence, drag is a type of frictional force where air offers resistance to the motion of the object.
Drag increases with the square of velocity. If velocity keeps increasing, drag keeps increasing too, until it becomes equal to the weight of the object. When drag is equal to weight, there is no net external force on the object and the vertical acceleration reduces to zero. With no acceleration, the object falls with a constant vertical velocity, called as the terminal velocity.
This activity investigates effect of drag coefficient of an object falling through air. The drag coefficient is largely determined by the shape of the object.
The activity consists of two trials, featuring four geometric solids made up of aluminum and having the same mass and frontal area. The first trial involves dropping an aluminum sphere and cuboid from a hot air balloon at a specific height above ground.
DIY - Ideal gas law - Effect of moles of gas on exerted pressure
This DIY interactive investigates the effect of change in the amount (moles) of gas on the pressure it exerts in an enclosed container, with temperature and volume 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 activity consists of two trials, each involving a gas in an enclosed cylinder whose moles change over time to observe the corresponding change in pressure. For each trial, you can specify the values of constant temperature, constant volume and the starting number of moles.
Note: The interactive includes a simplified model of motion of gas molecules, where pressure can be thought of as the aggregation of collisions of the molecules on the walls of the cylinder and the piston, such that more the collisions, higher the pressure exerted by gas, and vice versa. The speed of molecules is governed by temperature, such that higher the temperature, greater the speed of the gas molecules.