Now it's the end of week one, let's do an assignment, and this assignment would involve all of you, all the students of this course. We're trying to do a worldwide mapping of the taste map of our tongue. Let's look at what happen. On this particular map, I'll indicate to you that this is the tongue. On the tongue, that's the very inner area, I call it a. And on both sides, at the back, I call it b. More towards the front I call it c. And the tip of your tongue is d. So I want to understand, which part of this area on the tongue, in fact is used for sensing certain tastes? Okay, I need to have my assistant to come in. Leo, right. So what you're supposed to do, is that you are going to use one of these solution. For example, this one. This is one of the solution, and what I'm going to do. We follow a procedures like this. You can prepare different kind of solution. For example, if you wanted a sweet solution, you would have sugar, two teaspoons of sugar in 100ml of water. for sourness we use either lemon juice or vinegar. We can use water as the blank. We can have some salt, table salt in water to have the salty solution. We can have some cocoa powder put in water to represent bitterness. Now, what we need is, we need to use a cotton swab. This particulat solution represent one of these. So what are we supposed to do? What we are going to do, is we are going to use this cotton swab. We dip it into the solution, and then what we'll put is that we ask my assistant to stick his tongue out. And then I'll try to put this particular solution on a particular spot. Lets say this time I want to try tongues tip, here. And then what I want you to do, is that after you try it, you would rank well, is this one sweet? Is this one salty, is it sour or bitter?

And if this salty. What level of saltiness is it? So rank it, with the grade of 1 to 4. 4 being the strongest. And then you write that down. Now, and then I go back, and use another swab. Dip it, and then put it in, and then ask if, now if I put it a second position. For example, to a very interior part of the tongue, or on the side of the tongue. Then you would have a score for each particular spot, for the same solution, and you rank them according to intensity. And after you have done all this, what you're going to do is you're going to take all this data and tabulate on a table. So what you're suppose to do, is then afterward on the course website, you're going to be prompted with some of the questions. So what you need to do, is to write down if you're trying the first solution. For example, whether it's a sweet solution, 1, 2, 3, and 4, accordingly. And you rank them. If you put it on the position a, b, c, and d. What's the intensity of a particular taste? Now after we've collected all those, we will be able to integrate all the data from thousands and thousands of students input, and we're going to have a taste map with the input of all of you. And then next week, I'll tell you what the taste map of human beings are.