Cookies experiment Aim: To find out what type of powder reacts more towards heat and therefore expanding inside a cookie mix. Prediction: Based on the research I maid I think that the powder with the least different type of carbohydrates and elements wi

Variables:

• Independent: The type of powder added to the cookie mix
• Dependent: Change in length of cookie after being baked
• Controlled: Mass of cookie mix for each cookie, amount of powder added, heat of oven, surface on which it was cooked on, type of cookie mix (ingredients), shape of the cookie, ruler used to measure and time inside oven.

Research: Coffee has caffeine with the chemical formula C8H10N4O2, this means that there are many particles to make the coffee increase temperature. Caffeine constitutes of 2.5 % of an average coffee grain, the rest are many different type of carbohydrates consisting of 50 % of coffee beans.

Sugar is made up of carbohydrates for the 99% of it; the two main carbohydrates are glucose with the molecular formula C6H12O6 and fructose. The sugar will start to liquefy at 170ºC but will take time to become completely into a liquid.

Chocolate powder is mainly made up of sugar meaning that a similar reaction will take place, it has a lot of carbohydrates and very few of other types of molecules such as iron and calcium. Cereal will also likely react like sugar because it contains large amount of it.

Cinnamon mainly consists of the carbohydrate that gives it its odor and taste called cinnamaldehyde the molecular formula is C9H8O. Given that the carbohydrate that is most abundant is smaller than the others I believe that it is the one to become hotter faster and therefore making its surroundings further apart from each other.

Results: There are very few results because the experiment didn’t required a second or third trial to find anomalous results. I think the only thing that could have gone wrong when measuring the results is incorrect reading from the ruler that could be done again if it went wrong; this meant that repetition of the main test wasn’t required.

*One teaspoon of powder

Calculations: The only calculation made was subtracting the starting length of the cookie with the powder from the final length of the cookie after being baked. Making this calculation resulted in the difference of the cookies length, this was useful to see how much the powder expanded inside the cookie mix.

Conclusion: My prediction wasn’t accurate because sugar was the powder that increased the length of the cookie. The fact of the sugar melting at 170ºC could have meant that it most likely did melt by the time the cookies were baked. The other possibility could be that the other type of powders had many different sorts of molecules with stronger bonds. The least reactive type of powder towards heat was in fact cinnamon meaning that because it is a smaller hydrocarbon it has stronger bonds. These results can also be due to the cinnamon having other properties, which even though they are in small quantities per grain they, can be the thing stopping the cinnamaldehyde from heating up faster. The main problems with the controlled variables were that they were difficult to measure without the right equipment. The temperature of the oven was difficult to be kept because the oven thermometer didn’t have precise measurements, the balance to weight the cookie mass had the same problem of having very big differences between units. The volume of the powder could only be measured with a teaspoon that isn’t very accurate and could vary. The only controlled variable that was possible to kept very constant was the time the cookies were inside the oven.

Evaluation: The results gotten might be incorrect because of several different reasons; not being able to correctly read of the results of a ruler or measuring a different length of the cookie to the one measured before baking the cookies. Another source of error may be not being able to keep the constant variables the same throughout the experiment.

I believe that my method is clear to follow although it is quite extensive for just one trial of the experiment. The only thing that I think isn’t clear in the method is the cookie mix I used, I believe it isn’t very relevant because according to me the thing that is being tasted is how much does the molded mix change in size when it has a certain type of powder and not how it reacts to the type of cookie mix the powder has around it.