about sharks teeth (facts from scientist website)

In fact, if it weren’t for shark’s teeth, we would know very little about prehistoric sharks at all! Since sharks are cartilaginous fish, their teeth are often the only part of their bodies that entered the fossil record. This is because shark teeth are modified placoid scales, which, like our own teeth, consist of a central pulp cavity surrounded by dentine and a hard enamel surface. Shark teeth are used almost exclusively to classify ancient species of sharks. Some prehistoric sharks are known to scientists only by the shape and size of their teeth.When you consider the number of teeth a shark uses during this lifetime, this information is hardly a surprise. A shark’s teeth are arranged in rows, the number of which varies from species to species. The row nearest the front of the mouth is the “working” row of teeth (though some sharks use up to the first 8 rows of teeth), and they are the largest teeth in a sharks’ mouth. The second row of teeth is smaller than the first row of teeth, the third row of teeth is smaller than the fourth row, and so on. Every time a shark loses a tooth, the tooth in the row behind it moves up to take the lost tooth’s place. This is possible because sharks’ teeth are not embedded in the jaw, but are attached to the skin covering the jaw.New teeth are continually grown in a groove in the shark’s mouth and the skin acts as a “conveyor belt” to move the teeth forward into new positions. Sharks’ specialized teeth have allowed sharks to develop a very strong jaw. Without the ability to quickly replace teeth, a shark’s jaw could not have developed as powerful of a bite. The number of teeth they routinely lose while catching prey would outweigh the quick-kill benefits of their crushing jaw strength.Sharks that typically eat fish have long, narrow, needle-like teeth ideal for gripping something as slippery and streamlined as a fish.Tiger sharks, great white sharks, and other sharks that primarily eat seals and other mammals have sharp, serrated cutting teeth for tearing off chunks of flesh.Finally, we have the gentle giants of the shark family, the basking sharks and whale sharks, that eat krill and other forms of plankton. While they have many teeth, they are tiny and useless, as these sharks feed by filtering water through their gills. https://www.sharksavers.org/en/education/biology/shark-teeth1/

4E INQUIRY PROJECTS

Please enjoy our Inquiry Projects!  Our class chose 5 questions and set out to discover some answers. We followed a process of inquiry that scientists use called the Scientific Method.  Each post below takes us on a journey through these six steps:

4th Grade, you did a stupendous job!  Thanks for all your hard work.  A VERY special THANK YOU to Ms. Graham for all the help she was to us!!!!

Payton's Inquiry-Popcorn

1.  Why does popcorn pop?

2. http://www.hometrainingtools.com/popcorn-science-project/a/1561/

  http://www.popcorn.org/ForTeachers/TeachingGuide/WhatMakesPopcornPop/tabid/88/Default.aspx

• As the kernel heats up, the water begins to expand.  
• Popcorn is a marvel.
• The pressure inside the grain will reach 135 pounds per square inch before finally bursting the hull 
  open.
  
  

3. Hypothesis:  I think popcorn pops so you can eat the popcorn.

4.

5. The popcorn was spinning and it took awhile to pop and it popped. I saw the steam and it started to go up.

6. Popcorn pops because there is water in the popcorn. Then the water heats up. Then the popcorn is heats up to 347 degrees. The water gets bigger and then the popcorn pops.

Grace's Inquiry-Marshmallows

1.  Why do marshmallows expand in the microwave?

2.   http://scienceline.ucsb.edu/getkey.php?key=783

http://www.newton.dep.anl.gov/askasci/chem03/chem03338.htm

• I learned marshmallows have tiny holes.                                                            

• I learned they’re made of sugar.
• I learned they expand in heat.

3.  Hypothesis:  The heat melts them to make them gooey.

http://www.newton.dep.anl.gov/askasci/chem03/chem03338.htm

4.

5.  It deflated and it got crispy.  I really like it crispy.

6.  I guessed that because the heat would make marshmallows expand and make them gooey.  They expand because it is full of air.  The air then expands and gets all gooey.  They’re made of gelatin that melts fast.

Eric's Inquiry-Yeast

1.  Why does yeast make bread rise?

2. http://www.finecooking.com/articles/yeast-role-bread-baking.aspx

http://questionmaster.hubpages.com/hub/Why-does-bread-rise-dough

• I learned that the yeast goes up because of sugar.
• I learned that when the yeast goes up it pushes air.
• I learned that when the air pushes up it blows up the balloon.

3.  Hypothesis:  I think the reason bread rises is that as it is eating the sugar, it creates more bread and as it is creating more bread it is pushing air out to make the balloon blow up.

4.

5.  As yeast is eating the sugar, it is blowing up the balloon.

6. I learned that the yeast rises from sugar and pushes air in the balloon.

Kayley`s Inquiry-Popcorn

                                               
                                             1.  Why does popcorn pop?

2.  http://www.tellmewhyfacts./2006/11/why-does-popcorn-pop.html

http://www.newton.dep.anl.gov/askasci/chem99/chem99165.htm

• I learned that popcorn has water in it.                
• I learned that popcorn pops because the heat makes it jump around and pop.
• Lastly, I learned that when popcorn gets so hot steam and water comes out.

 

  3.      My hypothesis: It pops because the heat pops it.

4.

             

5.  I saw that the test tube burned and that steam and water came out. A cloud of steam traveled up the tube.

   

      

6.  I did not know that popcorn had water in it. I just learned that Friday. My hypothesis was half correct. It was half of how popcorn pops. It is like the water’s being boiled and the steam pushes the popcorn kernel and it pops open.  It was really cool to learn this and it was fun.                       

AJ's Inquiry-Salt

1.  Why do we add salt to food?

2.  http://www.explorecuriocity.org/Content.aspx?contentid=164

http://www.thekitchn.com/food-science-salting-to-taste-49868

• I learned that we can detect four tastes- sweet, sour, bitter, and salt.
• I learned that if you have a dish that tastes flat or bitter, a little salt might be the only fix you need.
• Too much salt, however, can cause high blood pressure and damage to blood vessels.

3.  Hypothesis: maybe to make food taste really good.

4.

 

5.  It was bubbling a lot.  It tasted gross. The water made me sick. This tonic water was really nasty. The tonic water was bubbling when I put some salt in it.     

6.  My hypothesis was correct.  Salt is used to make food taste better.  It cancels the bitter and makes it taste better.