Touch

Objective:

The objective of this lab is to learn about our sense of touch

Background on

Our sense of touch helps us to determine temperature of different things. Thermoreceptors help us to sense the temperature of things around and touching us. If something is too hot our sense of touch will alert our brain and have us pull away from the object. It can also help us identify if things are too cold. By feeling the temperature of different things we can sense what is safe and what is dangerous in our environment in terms of temperature. Cold receptors send signals to the brain when our skin temperature drops below 95 F. You will feel the cold most when your skin is at 77 F, and will have your hands and feet go numb when your skin temperature drops below 41 F. Hot receptors send signals to our brain when our skin temperature rises above 86 F and are most active when your skin reaches 113 F, but temperatures above 113F cause our pain receptors to take over in order to avoid damage to the body.

Mechanoreceptors are receptors that respond to mechanical pressure or distortion, think of them as receptors that have to be pushed on in some way in order for us to feel a signal from them. Hair receptors help you to feel light touches, such as a gentle brush of a feather or a light breeze. Meissner Corpuscle receptors help your body to feel slipping objects, like your hands sliding across each other. Pacinian Corpuscle receptors help you to feel the vibration of an object when you hold it, think of a fidget spinner spinning in your hand these receptors help you feel the vibration created by that spin. Merkel cell-neurite complex receptors help us feel differences in surfaces that we touch, think of Braille (a raised form of writing used by people with poor or no eye sight), these receptors allow us to feel the different raised bumps and distinguish them from other raised bumps. Ruffini Corpuscle receptors are used to help us maintain grip on an object, think about holding a snack bag these receptors help you keep the right amount of pressure between your finger tips so that the snack bag does not fall. C-Fibre LTM receptors help us to feel the positive feelings associated with a hug or handshake. Mechano-nociceptor polymodal nociceptor receptors are used to sense pain, like when we get a sting from a bee. 

Pain receptors are used to protect the body from harm. They can detect pain that is caused by mechanical stimuli (cut or scrape), thermal stimuli (burn), or chemical stimuli (poison from an insect sting). Pain receptors cause you to feel a sharp pain (meant to get you to pull away quickly to avoid further injury) or a dull ache (meant to keep you from using an already injured part).

Proprioceptor receptors are used to help us relate where parts of our body are in relation to other things. Proprioceptors are found in tendons, muscles, and joint capsules. This location in the body allows these special cells to detect changes in muscle length and muscle tension. Without proprioceptors, we would not be able to do fundamental things such as feeding or clothing ourselves. It helps us know if a surface is solid or squishy. It can also helps us know if the surface will cause us to slip or if we will be safe to walk. It can tell us if something is soft or hard. Helping us to determine how hard to throw something like a ball to get it to land where we want it too. It can tell us if something is sharp or dull. Which can keep us from cutting ourselves on dangerous things.

Materials

•        4 oz. General Purpose Glue (not washable)

•        8 oz. Water (4 oz. and 4 oz.)

•        1 tsp. Borax

•        Glitter or food coloring if desired

Method

Prepare Experiment

• Gather all materials neatly in front of you

Run Experiment

1. What did the glue feel like before you added the water? How did it change when the water was added?
2. Add 4 oz. Water and 4 oz. Glue together and stir until fully mixed (add glitter or food coloring if desired)
3. What did the Borax feel like before it was dissolved? How did the feeling of the water change when the Borax was added to it?
4. Add 4oz. Warm water and 1 tsp. Borax together and stir until fully dissolved
5. Add Borax solution and Glue solution together and stir
6. How does mixing the two solutions together change the texture?
7. Knead for 5 – 10 minutes
8. As you knead the solution how does the texture change? Does it continue to be a few different liquids?
9. Play
10. Store in airtight container

Analyze Data

The water should feel warm to the touch and wet. When you touch the glue it should be sticky and runny on your fingers. When you mix the two together the feeling should change where the solution no longer feels warm and the glue should run much faster through your fingers and should feel just a bit less sticky. The Borax when on its own is a crumbly, sometimes sharp solid that should feel hard in your fingers and most likely will not seem to be hot or cold. When mixed into the water you may feel some slimy texture to the new solution. When you pour everything together you will notice that the area that the Borax gets poured into the glue solution will get hard going from a liquid to a solid almost instantly. The more you knead the solution the more of it that will go from a liquid to a solid. Initially the solid will be very stringy but will become smooth the more it is worked. All of these changes can be felt through the touch receptors on our hands.

Conclusions

In this lab we learned all about our sense of touch and how the feeling of one thing can change over time or with mixing with other materials. In mixing materials together we were able to go from a sticky warm touch sensation to a cool smooth solid sensation. The change in the feeling that we experienced was perceived throughout the entire process by the receptors on our skin. In our bodies we have receptors for feeling inside and out, even on our tongue! When we look at how important our sense of touch is and how ignored it can be it is amazing to think that without it we would not be able to do the simplest task, so the next time your parents tell you to be careful or to bundle up make sure you listen to them so that you keep all those amazing receptors in tip top form.

Make It Your Own

Do you think that mixing any ingredients together will give you the same outcome? What do you think would happen if you simply mixed the glue and the Borax together without using the warm water? Do you think you can make the exact same material without any issues? Try and see what you come up with? If it does not work think of why this may not have worked and ask yourself is it easier to mix together two liquids or to mix together a solid and a liquid?

Extension Activities to do at home

Now let’s use our amazing sense of touch at home. Make sure you get your parents permission before you mix anything together to see what it feels like as some things mixed together could be very dangerous (avoid mixing or even touching any cleaning products or your parents tools/knives). If your parents say it is alright try mixing together the ingredients to make biscuits, I would suggest doing ¼ recipes in which you will make small batches as you explore.