Editing Blood Clotting

{| class="wikitable" style="color:black; background-color:#ddd; margin-left: auto; float:right"
| [[Biology]]:
| Blood Clotting, Parts of the Blood
|-
| Grade Range:
| [[Elementary School]], [[Middle School]]
|-
| Format:
| [[Stage]]
|}

This demonstration shows students how the blood clots, and what parts of the blood help in the blood clotting process. This is a good supplemental demonstration on the topic of blood.

== Materials ==

* Blood Clotting Box with Membrane Lid and Cutout
* Blower
* Red Balloons
* Paper

== Safety Precautions ==

Please read the General Safety section of the [[Demonstration Safety]] page before performing this demonstration.

== Demonstration ==

Preparation: Blow up all the red balloons and place them inside the box. Be sure that you can still get the lid on with the balloons inside the box, and place the cutout over the membrane. Make sure to plug in the blower.
# Show the box, and ask for one or two students to be volunteers for this demonstration. Explain that the box represents the skin, and remove the lid to indicate a cut. Use the blower to blow the balloons out, and have the volunteers collect them.
# Now place the paper sheets across the balloons in the box. Show that this is a temporary barrier by using the blower to blow the balloons out again. Have the volunteers collect the balloons again.
# Finally, place the paper sheets across and then put the membrane lid on top. show that this holds the balloons inside the box, and finish by showing that this will allow the skin to reform by putting the cutout back on top.


== Why This Works ==

Wound healing is an important property of our bodies. When the skin is injured and cut, there are three stages to the recovery process we call ''Hemostasis''. The first stage is when the platelets in the blood start to stick together at the injury site. ''Platelets'' are flat cells in the blood which, when activated, will stick to each other at the injury site, and release a chemical response to encourage other platelets to stick there as well. This stage is when you first see that a cut has stopped bleeding, and there is a semi-clear blob on the cut. If you poke this, however, then the cut will reopen and continue to bleed, since the platelets are only a short term fix. The second stage is when fibrin starts to collect at the injury site. ''Fibrin'' is a protein in the blood which, when activated, creates a strong membrane over the injury site. This is when a cut has a scab on it, and scabs are much harder to break. The third stage is when the body does the repairs at the location by removing the dead cells and replacing them with live cells. During this part the fibrin and platelets will be re-dissolved into the blood, the skin will grow back, and the cut will be healed! 

== Additional Information ==

* This demonstration pairs well with the [[Blood And Buffers]] demonstration.