Half life

 Today you will work on the concept of "Half Life"  and you will be given a worksheet.  If you missed the class, then this youtube video explains the same concepts that we went over in class.  The answer key is found here under 7.2 

How Hot is Our School?

PURPOSE:

Today is forecast to be a very hot day.  Our purpose in our experiment today is to take data on the temperature of our school by photographing calibrated thermometers

Procedure:

1. Write a hypothesis on the areas of the school which are predicted to be hotter than other areas.  What factors contribute to heat gain in these areas?   Which areas are predicted to be cooler areas?  Measure both outdoor and indoor areas.  For example, if you are outdoors, sample areas of shade, north, south, east west exposure, on concrete or on grass.  If you are indoors, sample areas with windows or blinds open, closed, sample different floors, occupancy, etc.

2.   Quantitative data: Decide on 10 areas of the school to sample. Photograph your thermometer and note the time and location.   

3. Qualitative data:  Besides observing the temperature, time and location, note how you feel in the area.  Does the location feel like a hotspot? Is it comfortable?  Is it uncomfortable?

Results:

Create a powerpoint to record the photograph of your thermometer and note the location and time and your qualitative observations. 

Conclusion:

1. Was your hypothesis correct? 

2. What areas of the school had the highest temperatures and lowest temperatures?  

3. What factors influenced the temperatures in these locations?

4.  What areas of the school can be repurposed as an in school cooling area?  

Calculating Einstein's Equation

  In the nuclear reaction shown, a neutron (moving with negligible kinetic energy) hits a Uranium-235 nucleus. The resulting unstable nucleus  undergoes fission 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 

Now plug in the difference into Einstein's equation

Fusion and Fission

 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 

Here is the powerpoint on the nuclear bomb

introduction to Nuclear Fission and Fusion

Watch these two introductory videos on Fission and Fusion.  The Teacher will review the worksheet on Fission and Fusion and go over examples. You can practice these questions. 

That Dress! and the science of perception

 

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

  

sex linkage

  SEX LINKED GENES

In the following post, I will refer to the term  "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= has male sex organs like testes, producing male gametes such as sperm

female= has female sex organs like ovaries, producing female gametes such as  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 ! 

 

Colour blind test

Basic practice worksheet going over main concepts

Worksheet B