Wednesday 15 May 2024

EM scavenger hunt

 



First block 

1.  A wave with a frequency that is slower than infrared waves and faster than radio waves 

2.   Find some food that is radioactive

3.   Americium

4.   Someone who got radiation *on purpose * 

5.  find something with radio waves  

6.  Find something that filters radiation


Second block  

take a pic of a sign that says the following materials and point to the material 

1.  a radioactive food

2.a   Something that makes  a with a frequency wave slower than infrared wave and which can transmit images and sound.

3.   Someone who has had radiation on purpose & the radiation has a faster wavelength than UV

4.   Someone with something that *filters* UV light 

5.  Something that makes waves with a frequency that is slower than infrared, faster than radio waves 

6.  something with Americium 

Monday 13 May 2024

Calculating the mass difference

In the nuclear reaction shown, a neutron (moving with negligible kinetic energy) hits a Uranium-235 nucleus. The resulting unstable nucleus fissions into Krypton-92, Barium-141, and three neutrons.

Data:
Uranium-235 mass: 390.300x10^-27 kg
Krypton-92 mass: 152.647x10^-27 kg
Barium-141 mass: 233.994x10^-27 kg
Neutron mass: 1.675x10^-27 kg

a) What is the total mass of the pieces going into the reaction?
b) What is the total mass of the pieces coming out of the reaction?
Calculate the mass difference

Introduction to Radioactivity

 Here are the Fusion and Fission notes 

I gave you a worksheet called 7.3 Nuclear Reactions, the answer key to that is here
There is also the Radioactive unit exam study guide  and Answer key 

Wednesday 1 May 2024

that dress

 



There is a very interesting dress. It has caused major arguments!  This dress causes your cells in your retinas to perceive it to be certain colours depending on the state of your retinas. Of course your genes determine what your retinas are like...but also your retinas change over time too!  

Your perception is also based on whether you think this dress is in shadow or light...Try this, 

 I would like you to ask  20 people you know "What colours do you see on this dress:  Is it :  

A. GOLD AND WHITE 

B.  BLACK AND BLUE

C.  GOLD AND BLUE

D.  NONE OF THE ABOVE...THEN what colour is it?  

What are the characteristics of the people who are more likely to say that it is any of the choices above?   

Remember you can poll people without meeting face to face. Ask a variety of people including old, young, male, female...put your results on a table and hypothesize why people see different colours


X-linked genes

 SEX LINKED GENES

In the following post, I will refer to "male" and "female".  This refers to people with male sex organs or people with female sex organs.  People with these organs can identify with a diverse range of gender such as:

Man, woman, nonbinary. This gender identify is not presumed by the presence of male or female sex organs

They might also identify as
LGBTQ2S++

The following descriptions are biological descriptions refer to 
male= male sex organs like testes, producing sperm
female= female sex organs like ovaries, producing eggs. 


The sex chromosomes are XX and XY in humans. Some alleles are located on the X chromosome. But very few on the Y chromosome.  Remember that people who are  females have the genotype XX and people who are males have XY.

The Y chromosome carries very little information, only enough to influence the embryo on the path towards male primary and secondary characteristics.

Meanwhile, many RECESSIVE ALLELES are located on the X chromosome, including
1. hemophilia, the inability to clot blood
2. colourblindness inability to tell the difference between red and green colour
3.  baldness

These characteristics are far more common in people with male sex organs  than people with female sex organs because  people with male organs have only one X. And if that X contains the recessive allele, they will show the phenotype.  Meanwhile,people with  female organs may have the recessive and their dominant genes on their other X will protect them.  For example
An example of using a punnet square to calculate probability is here:



Some things to note about sex linkage:  Signs of sex linked alleles are:
1. more genotypic males get the phenotype, but genotypic females can be carriers
2.  males can inherit from mother but not father (because males get their X from mom)
3.  genotypic females have an extra X and this protects them.  Females must be homozygous to show the sex linked phenotype.
Further reading on sex linkage here http://learn.genetics.utah.edu/content/pigeons/sexlinkage/

FYI if you were born a male and you want to know if you're colourblind:  Test yourself here: But careful, if you are a genetically male, you might find out you are colour blind!  Apparently most people find out they are colourblind from their science teacher !  
http://colorvisiontesting.com/home.html



Basic practice worksheet going over main concepts